33 changed files with 313 additions and 5870 deletions
--- a/CLAUDE.md
+++ b/CLAUDE.md
@ -55,7 +55,7 @@ No build step required - Bun runs TypeScript directly.
 ### Critical Design Decisions
-**Label-based jumps**: All JUMP instructions (`JUMP`, `JUMP_IF_FALSE`, `JUMP_IF_TRUE`) require label operands (`.label`), not numeric offsets. Labels are resolved to PC-relative offsets during compilation, making bytecode position-independent. PUSH_TRY/PUSH_FINALLY use absolute addresses and can accept either labels or numeric offsets.
+**Relative jumps**: All JUMP instructions use PC-relative offsets (not absolute addresses), making bytecode position-independent. PUSH_TRY/PUSH_FINALLY use absolute addresses.
 **Truthiness semantics**: Only `null` and `false` are falsy. Unlike JavaScript, `0`, `""`, empty arrays, and empty dicts are truthy.
@ -137,100 +137,40 @@ Array format features:
 - Function params as string arrays: `["MAKE_FUNCTION", ["x", "y=10"], ".body"]`
 - See `tests/programmatic.test.ts` and `examples/programmatic.ts` for examples
-### Native Function Registration and Global Values
+### Native Function Registration
 **Option 1**: Pass to `run()` or `VM` constructor (convenience)
 ```typescript
 const result = await run(bytecode, {
  add: (a: number, b: number) => a + b,
-  greet: (name: string) => `Hello, ${name}!`,
+  greet: (name: string) => `Hello, ${name}!`
  pi: 3.14159,
  config: { debug: true, port: 8080 }
 })
 // Or with VM constructor
-const vm = new VM(bytecode, { add, greet, pi, config })
+const vm = new VM(bytecode, { add, greet })
 ```
-**Option 2**: Set values with `vm.set()` (manual)
+**Option 2**: Register with `vm.registerFunction()` (manual)
 ```typescript
 const vm = new VM(bytecode)
-
+vm.registerFunction('add', (a: number, b: number) => a + b)
 // Set functions (auto-wrapped to native functions)
 vm.set('add', (a: number, b: number) => a + b)
 // Set any other values (auto-converted to ReefVM Values)
 vm.set('pi', 3.14159)
 vm.set('config', { debug: true, port: 8080 })
 await vm.run()
 ```
-**Option 3**: Set Value-based functions with `vm.setValueFunction()` (advanced)
+**Option 3**: Register Value-based functions (for direct Value access)
 For functions that work directly with ReefVM Value types:
 ```typescript
-const vm = new VM(bytecode)
+vm.registerValueFunction('customOp', (a: Value, b: Value): Value => {
 // Set Value-based function (no wrapping, works directly with Values)
 vm.setValueFunction('customOp', (a: Value, b: Value): Value => {
  return toValue(toNumber(a) + toNumber(b))
 })
 await vm.run()
 ```
 Auto-wrapping handles:
- Functions: wrapped as native functions with Value ↔ native type conversion
+- Value ↔ native type conversion (`fromValue`/`toValue`)
 - Sync and async functions
 - Arrays, objects, primitives, null, RegExp
 - All values converted via `toValue()`
-### Calling Functions from TypeScript
+### Label Usage (Preferred)
-
+Use labels instead of numeric offsets for readability:
 Use `vm.call()` to invoke Reef or native functions from TypeScript:
 ```typescript
 const bytecode = toBytecode(`
  MAKE_FUNCTION (x y=10) .add
  STORE add
  HALT
  .add:
    LOAD x
    LOAD y
    ADD
    RETURN
 `)
 const vm = new VM(bytecode, {
  log: (msg: string) => console.log(msg)  // Native function
 })
 await vm.run()
 // Call Reef function with positional arguments
 const result1 = await vm.call('add', 5, 3)  // → 8
 // Call Reef function with named arguments (pass final object)
 const result2 = await vm.call('add', 5, { y: 20 })  // → 25
 // Call Reef function with all named arguments
 const result3 = await vm.call('add', { x: 10, y: 15 })  // → 25
 // Call native function
 await vm.call('log', 'Hello!')
 ```
 **How it works**:
 - Looks up function (Reef or native) in VM scope
 - For Reef functions: converts to callable JavaScript function using `fnFromValue`
 - For native functions: calls directly
 - Automatically converts arguments to ReefVM Values
 - Converts result back to JavaScript types
 ### Label Usage (Required for JUMP instructions)
 All JUMP instructions must use labels:
 ```
 JUMP .skip
 PUSH 42
@ -240,67 +180,6 @@ HALT
  HALT
 ```
 ### Function Definition Patterns
 When defining functions, you MUST prevent the PC from falling through into function bodies. Two patterns:
 **Pattern 1: JUMP over function bodies (Recommended)**
 ```
 MAKE_FUNCTION (params) .body
 STORE function_name
 JUMP .end              ; Skip over function body
 .body:
  <function code>
  RETURN
 .end:
  <continue with program>
 ```
 **Pattern 2: Function bodies after HALT**
 ```
 MAKE_FUNCTION (params) .body
 STORE function_name
 <use the function>
 HALT                   ; Stop before function bodies
 .body:
  <function code>
  RETURN
 ```
 Pattern 1 is required for:
 - Defining multiple functions before using them
 - REPL mode
 - Any case where execution continues after defining a function
 Pattern 2 only works if you HALT before reaching function bodies.
 ### REPL Mode (Incremental Execution)
 For building REPLs (like the Shrimp REPL), use `vm.continue()` and `vm.appendBytecode()`:
 ```typescript
 const vm = new VM(toBytecode([]), natives)
 await vm.run()  // Initialize (empty bytecode)
 // User enters: x = 42
 const line1 = compileLine("x = 42")  // No HALT!
 vm.appendBytecode(line1)
 await vm.continue()  // Execute only line 1
 // User enters: x + 10
 const line2 = compileLine("x + 10")  // No HALT!
 vm.appendBytecode(line2)
 await vm.continue()  // Execute only line 2, result is 52
 ```
 **Key points**:
 - `vm.run()` resets PC to 0 (re-executes everything) - use for initial setup only
 - `vm.continue()` resumes from current PC (executes only new bytecode)
 - `vm.appendBytecode(bytecode)` properly handles constant index remapping
 - Don't use HALT in REPL lines - let VM stop naturally
 - Scope and variables persist across all lines
 - Side effects only run once
 ## TypeScript Configuration
 - Import alias: `#reef` maps to `./src/index.ts`
@ -486,7 +365,7 @@ Run `bun test` to verify all tests pass before committing.
 ## Common Gotchas
-**Label requirements**: JUMP/JUMP_IF_FALSE/JUMP_IF_TRUE require label operands (`.label`), not numeric offsets. The bytecode compiler resolves labels to PC-relative offsets internally. PUSH_TRY/PUSH_FINALLY can use either labels or absolute instruction indices (`#N`).
+**Jump offsets**: JUMP/JUMP_IF_FALSE/JUMP_IF_TRUE use relative offsets from the next instruction (PC + 1). PUSH_TRY/PUSH_FINALLY use absolute instruction indices.
 **Stack operations**: Most binary operations pop in reverse order (second operand is popped first, then first operand).
--- a/GUIDE.md
+++ b/GUIDE.md
@ -179,25 +179,12 @@ PUSH 1              ; Named count
 CALL
 ```
 **Null triggers defaults**: Pass `null` to use default values:
 ```
 ; Function: greet(name='Guest', msg='Hello')
 LOAD greet
 PUSH null           ; Use default for 'name'
 PUSH "Hi"           ; Provide 'msg'
 PUSH 2
 PUSH 0
 CALL                ; → "Hi, Guest"
 ```
 ## Opcodes
 ### Stack
 - `PUSH <const>` - Push constant
 - `POP` - Remove top
 - `DUP` - Duplicate top
 - `SWAP` - Swap top two values
 - `TYPE` - Pop value, push its type as string
 ### Variables
 - `LOAD <name>` - Push variable value (throws if not found)
@ -207,10 +194,6 @@ CALL                ; → "Hi, Guest"
 ### Arithmetic
 - `ADD`, `SUB`, `MUL`, `DIV`, `MOD` - Binary ops (pop 2, push result)
 ### Bitwise
 - `BIT_AND`, `BIT_OR`, `BIT_XOR` - Bitwise logical ops (pop 2, push result)
 - `BIT_SHL`, `BIT_SHR`, `BIT_USHR` - Bitwise shift ops (pop 2, push result)
 ### Comparison
 - `EQ`, `NEQ`, `LT`, `GT`, `LTE`, `GTE` - Pop 2, push boolean
@ -258,40 +241,6 @@ CALL                ; → "Hi, Guest"
 ## Compiler Patterns
 ### Function Definitions
 When defining functions, you must prevent the PC from "falling through" into the function body during sequential execution. There are two standard patterns:
 **Pattern 1: JUMP over function bodies (Recommended)**
 ```
 MAKE_FUNCTION (params) .body
 STORE function_name
 JUMP .end              ; Skip over function body
 .body:
  <function code>
  RETURN
 .end:
  <continue with program>
 ```
 **Pattern 2: Function bodies after HALT**
 ```
 MAKE_FUNCTION (params) .body
 STORE function_name
 <use the function>
 HALT                   ; Stop execution before function bodies
 .body:
  <function code>
  RETURN
 ```
 **Important**: Pattern 2 only works if you HALT before reaching function bodies. Pattern 1 is more flexible and required for:
 - Defining multiple functions before using them
 - REPL mode (incremental execution)
 - Any case where execution continues after defining a function
 **Why?** `MAKE_FUNCTION` creates a function value but doesn't jump to the body—it just stores the body's address. Without JUMP or HALT, the PC increments into the function body and executes it as top-level code.
 ### If-Else
 ```
 <condition>
@ -377,125 +326,6 @@ POP
 .end:                    ; Result on stack
 ```
 ### Reversing Operand Order
 Use SWAP to reverse operand order for non-commutative operations:
 ```
 ; Compute 10 / 2 when values are in reverse order
 PUSH 2
 PUSH 10
 SWAP                     ; Now: [10, 2]
 DIV                      ; 10 / 2 = 5
 ```
 ```
 ; Compute "hello" - "world" (subtraction with strings coerced to numbers)
 PUSH "world"
 PUSH "hello"
 SWAP                     ; Now: ["hello", "world"]
 SUB                      ; Result based on operand order
 ```
 **Common Use Cases**:
 - Division and subtraction when operands are in wrong order
 - String concatenation with specific order
 - Preparing arguments for functions that care about position
 ### Bitwise Operations
 All bitwise operations work with 32-bit signed integers:
 ```
 ; Bitwise AND (masking)
 PUSH 5
 PUSH 3
 BIT_AND                  ; → 1 (0101 & 0011 = 0001)
 ; Bitwise OR (combining flags)
 PUSH 5
 PUSH 3
 BIT_OR                   ; → 7 (0101 | 0011 = 0111)
 ; Bitwise XOR (toggling bits)
 PUSH 5
 PUSH 3
 BIT_XOR                  ; → 6 (0101 ^ 0011 = 0110)
 ; Left shift (multiply by power of 2)
 PUSH 5
 PUSH 2
 BIT_SHL                  ; → 20 (5 << 2 = 5 * 4)
 ; Arithmetic right shift (divide by power of 2, preserves sign)
 PUSH 20
 PUSH 2
 BIT_SHR                  ; → 5 (20 >> 2 = 20 / 4)
 PUSH -20
 PUSH 2
 BIT_SHR                  ; → -5 (sign preserved)
 ; Logical right shift (zero-fill)
 PUSH -1
 PUSH 1
 BIT_USHR                 ; → 2147483647 (unsigned shift)
 ```
 **Common Use Cases**:
 - Flags and bit masks: `flags band MASK` to test, `flags bor FLAG` to set
 - Fast multiplication/division by powers of 2
 - Color manipulation: extract RGB components
 - Low-level bit manipulation for protocols or file formats
 ### Runtime Type Checking (TYPE)
 Get the type of a value as a string for runtime introspection:
 ```
 ; Basic type check
 PUSH 42
 TYPE                     ; → "number"
 PUSH "hello"
 TYPE                     ; → "string"
 MAKE_ARRAY #3
 TYPE                     ; → "array"
 ```
 **Type Guard Pattern** (check type before operation):
 ```
 ; Safe addition - only add if both are numbers
 LOAD x
 DUP
 TYPE
 PUSH "number"
 EQ
 JUMP_IF_FALSE .not_number
 LOAD y
 DUP
 TYPE
 PUSH "number"
 EQ
 JUMP_IF_FALSE .cleanup_not_number
 ADD                      ; Safe to add
 JUMP .end
 .cleanup_not_number:
  POP                    ; Remove y
 .not_number:
  POP                    ; Remove x
  PUSH null
 .end:
 ```
 **Common Use Cases**:
 - Type validation before operations
 - Polymorphic functions that handle multiple types
 - Debugging and introspection
 - Dynamic dispatch in DSLs
 - Safe coercion with fallbacks
 ### Try-Catch
 ```
 PUSH_TRY .catch
@ -532,8 +362,7 @@ Functions automatically capture current scope:
 PUSH 0
 STORE counter
 MAKE_FUNCTION () .increment
-STORE increment_fn
+RETURN
 JUMP .main
 .increment:
  LOAD counter          ; Captured variable
@ -542,18 +371,6 @@ JUMP .main
  STORE counter
  LOAD counter
  RETURN
 .main:
  LOAD increment_fn
  PUSH 0
  PUSH 0
  CALL                  ; Returns 1
  POP
  LOAD increment_fn
  PUSH 0
  PUSH 0
  CALL                  ; Returns 2 (counter persists!)
  HALT
 ```
 ### Tail Recursion
@ -561,7 +378,7 @@ Use TAIL_CALL instead of CALL for last call:
 ```
 MAKE_FUNCTION (n acc) .factorial
 STORE factorial
-JUMP .main
+<...>
 .factorial:
  LOAD n
@ -581,15 +398,6 @@ JUMP .main
  PUSH 2
  PUSH 0
  TAIL_CALL             ; Reuses stack frame
 .main:
  LOAD factorial
  PUSH 5
  PUSH 1
  PUSH 2
  PUSH 0
  CALL                  ; factorial(5, 1) = 120
  HALT
 ```
 ### Optional Function Calls (TRY_CALL)
@ -733,8 +541,6 @@ Only `null` and `false` are falsy. Everything else (including `0`, `""`, empty a
 **Arithmetic ops** (ADD, SUB, MUL, DIV, MOD) coerce both operands to numbers.
 **Bitwise ops** (BIT_AND, BIT_OR, BIT_XOR, BIT_SHL, BIT_SHR, BIT_USHR) coerce both operands to 32-bit signed integers.
 **Comparison ops** (LT, GT, LTE, GTE) coerce both operands to numbers.
 **Equality ops** (EQ, NEQ) use type-aware comparison with deep equality for arrays/dicts.
@ -759,24 +565,11 @@ Variable and function parameter names support Unicode and emoji:
 ### Parameter Binding Priority
 For function calls, parameters bound in order:
-1. Named argument (if provided and matches param name)
+1. Positional argument (if provided)
-2. Positional argument (if provided)
+2. Named argument (if provided and matches param name)
 3. Default value (if defined)
 4. Null
 **Null Triggering Defaults**: Passing `null` as an argument (positional or named) triggers the default value if one exists. This allows callers to explicitly "opt-in" to defaults:
 ```
 # Function with defaults: greet(name='Guest', greeting='Hello')
 LOAD greet
 PUSH null    # Triggers default: name='Guest'
 PUSH 'Hi'    # Provided: greeting='Hi'
 PUSH 2
 PUSH 0
 CALL         # Returns "Hi, Guest"
 ```
 This works for both ReefVM functions and native TypeScript functions. If no default exists, `null` is bound as-is.
 ### Exception Handlers
 - PUSH_TRY uses absolute addresses for catch blocks
 - Nested try blocks form a stack
@ -813,18 +606,18 @@ const vm = new VM(bytecode, { add, greet })
 **Method 2**: Register after construction
 ```typescript
 const vm = new VM(bytecode)
-vm.set('add', (a: number, b: number) => a + b)
+vm.registerFunction('add', (a: number, b: number) => a + b)
 await vm.run()
 ```
 **Method 3**: Value-based functions (for full control)
 ```typescript
-vm.setValueFunction('customOp', (a: Value, b: Value): Value => {
+vm.registerValueFunction('customOp', (a: Value, b: Value): Value => {
  return { type: 'number', value: toNumber(a) + toNumber(b) }
 })
 ```
-**Auto-wrapping**: `vm.set()` automatically converts between native TypeScript types and ReefVM Value types. Both sync and async functions work.
+**Auto-wrapping**: `registerFunction` automatically converts between native TypeScript types and ReefVM Value types. Both sync and async functions work.
 **Usage in bytecode**:
 ```
@ -853,12 +646,12 @@ CALL                  ; → "Hi, Alice!"
 ```typescript
 // Basic @named - collects all named args
-vm.set('greet', (atNamed: any = {}) => {
+vm.registerFunction('greet', (atNamed: any = {}) => {
  return `Hello, ${atNamed.name || 'World'}!`
 })
 // Mixed positional and @named
-vm.set('configure', (name: string, atOptions: any = {}) => {
+vm.registerFunction('configure', (name: string, atOptions: any = {}) => {
  return {
    name,
    debug: atOptions.debug || false,
@ -883,121 +676,6 @@ CALL                ; atOptions receives {debug: true, port: 8080}
 Named arguments that match fixed parameter names are bound to those parameters. Remaining unmatched named arguments are collected into the `atXxx` parameter as a plain JavaScript object.
 ### Calling Functions from TypeScript
 You can call both Reef and native functions from TypeScript using `vm.call()`:
 ```typescript
 const bytecode = toBytecode(`
  MAKE_FUNCTION (name greeting="Hello") .greet
  STORE greet
  HALT
  .greet:
    LOAD greeting
    PUSH " "
    LOAD name
    PUSH "!"
    STR_CONCAT #4
    RETURN
 `)
 const vm = new VM(bytecode, {
  log: (msg: string) => console.log(msg)  // Native function
 })
 await vm.run()
 // Call Reef function with positional arguments
 const result1 = await vm.call('greet', 'Alice')
 // Returns: "Hello Alice!"
 // Call Reef function with named arguments (pass as final object)
 const result2 = await vm.call('greet', 'Bob', { greeting: 'Hi' })
 // Returns: "Hi Bob!"
 // Call Reef function with only named arguments
 const result3 = await vm.call('greet', { name: 'Carol', greeting: 'Hey' })
 // Returns: "Hey Carol!"
 // Call native function
 await vm.call('log', 'Hello from TypeScript!')
 ```
 **How it works**:
 - `vm.call(functionName, ...args)` looks up the function (Reef or native) in the VM's scope
 - For Reef functions: converts to callable JavaScript function
 - For native functions: calls directly
 - Arguments are automatically converted to ReefVM Values
 - Returns the result (automatically converted back to JavaScript types)
 **Named arguments**: Pass a plain object as the final argument to provide named arguments. If the last argument is a non-array object, it's treated as named arguments. All preceding arguments are treated as positional.
 **Type conversion**: Arguments and return values are automatically converted between JavaScript types and ReefVM Values:
 - Primitives: `number`, `string`, `boolean`, `null`
 - Arrays: converted recursively
 - Objects: converted to ReefVM dicts
 - Functions: Reef functions are converted to callable JavaScript functions
 ### REPL Mode (Incremental Compilation)
 ReefVM supports incremental bytecode execution for building REPLs. This allows you to execute code line-by-line while preserving scope and avoiding re-execution of side effects.
 **The Problem**: By default, `vm.run()` resets the program counter (PC) to 0, re-executing all previous bytecode. This makes it impossible to implement a REPL where each line executes only once.
 **The Solution**: Use `vm.continue()` to resume execution from where you left off:
 ```typescript
 // Line 1: Define variable
 const line1 = toBytecode([
  ["PUSH", 42],
  ["STORE", "x"]
 ])
 const vm = new VM(line1)
 await vm.run()  // Execute first line
 // Line 2: Use the variable
 const line2 = toBytecode([
  ["LOAD", "x"],
  ["PUSH", 10],
  ["ADD"]
 ])
 vm.appendBytecode(line2)  // Append new bytecode with proper constant remapping
 await vm.continue()       // Execute ONLY the new bytecode
 // Result: 52 (42 + 10)
 // The first line never re-executed!
 ```
 **Key methods**:
 - `vm.run()`: Resets PC to 0 and runs from the beginning (normal execution)
 - `vm.continue()`: Continues from current PC (REPL mode)
 - `vm.appendBytecode(bytecode)`: Helper that properly appends bytecode with constant index remapping
 **Important**: Don't use `HALT` in REPL mode! The VM naturally stops when it runs out of instructions. Using `HALT` sets `vm.stopped = true`, which prevents `continue()` from resuming.
 **Example REPL pattern**:
 ```typescript
 const vm = new VM(toBytecode([]), { /* native functions */ })
 while (true) {
  const input = await getUserInput()  // Get next line from user
  const bytecode = compileLine(input)  // Compile to bytecode (no HALT!)
  vm.appendBytecode(bytecode)  // Append to VM
  const result = await vm.continue()  // Execute only the new code
  console.log(fromValue(result))  // Show result to user
 }
 ```
 This pattern ensures:
 - Variables persist between lines
 - Side effects (like `echo` or function calls) only run once
 - Previous bytecode never re-executes
 - Scope accumulates across all lines
 ### Empty Stack
 - RETURN with empty stack returns null
 - HALT with empty stack returns null
--- a/IDEAS.md
+++ b/IDEAS.md
@ -1,500 +0,0 @@
 # ReefVM Architectural Improvement Ideas
 This document contains architectural ideas for improving ReefVM. These focus on enhancing the VM's capabilities through structural improvements rather than just adding new opcodes.
 ## 1. Scope Resolution Optimization
 **Current Issue**: Variable lookups are O(n) through the scope chain on every `LOAD`. This becomes expensive in deeply nested closures.
 **Architectural Solution**: Implement **static scope analysis** with **lexical addressing**:
 ```typescript
 // Instead of: LOAD x  (runtime scope chain walk)
 // Compile to: LOAD_FAST 2 1  (scope depth 2, slot 1 - O(1) lookup)
 class Scope {
  locals: Map<string, Value>
  parent?: Scope
  // NEW: Add indexed slots for fast access
  slots: Value[]  // Direct array access
  nameToSlot: Map<string, number>  // Compile-time mapping
 }
 ```
 **Benefits**:
 - O(1) variable access instead of O(n)
 - Critical for hot loops and deeply nested functions
 - Compiler can still fall back to named lookup for dynamic cases
 ---
 ## 2. Module System Architecture
 **Current Gap**: No way to organize code across multiple files or create reusable libraries.
 **Architectural Solution**: Add first-class module support:
 ```typescript
 // New opcodes: IMPORT, EXPORT, MAKE_MODULE
 // New bytecode structure:
 type Bytecode = {
  instructions: Instruction[]
  constants: Constant[]
  exports?: Map<string, number>  // Exported symbols
  imports?: Import[]               // Import declarations
 }
 type Import = {
  modulePath: string
  symbols: string[]  // [] means import all
  alias?: string
 }
 ```
 **Pattern**:
 ```
 MAKE_MODULE .module_body
 EXPORT add
 EXPORT subtract
 HALT
 .module_body:
  MAKE_FUNCTION (x y) .add_impl
  RETURN
 ```
 **Benefits**:
 - Code organization and reusability
 - Circular dependency detection at load time
 - Natural namespace isolation
 - Enables standard library architecture
 ---
 ## 3. Source Map Integration
 **Current Issue**: Runtime errors show bytecode addresses, not source locations.
 **Architectural Solution**: Add source mapping layer:
 ```typescript
 type Bytecode = {
  instructions: Instruction[]
  constants: Constant[]
  sourceMap?: SourceMap  // NEW
 }
 type SourceMap = {
  file?: string
  mappings: SourceMapping[]  // Instruction index → source location
 }
 type SourceMapping = {
  instruction: number
  line: number
  column: number
  source?: string  // Original source text
 }
 ```
 **Benefits**:
 - Meaningful error messages with line/column
 - Debugger can show original source
 - Stack traces map to source code
 - Critical for production debugging
 ---
 ## 4. Debugger Hook Architecture
 **Current Gap**: No way to pause execution, inspect state, or step through code.
 **Architectural Solution**: Add debug event system:
 ```typescript
 class VM {
  debugger?: Debugger
  async execute(instruction: Instruction) {
    // Before execution
    await this.debugger?.onInstruction(this.pc, instruction, this)
    // Execute
    switch (instruction.op) { ... }
    // After execution
    await this.debugger?.afterInstruction(this.pc, this)
  }
 }
 interface Debugger {
  breakpoints: Set<number>
  onInstruction(pc: number, instruction: Instruction, vm: VM): Promise<void>
  afterInstruction(pc: number, vm: VM): Promise<void>
  onCall(fn: Value, args: Value[]): Promise<void>
  onReturn(value: Value): Promise<void>
  onException(error: Value): Promise<void>
 }
 ```
 **Benefits**:
 - Step-through debugging
 - Breakpoints at any instruction
 - State inspection at any point
 - Non-invasive (no bytecode modification)
 - Can build IDE integrations
 ---
 ## 5. Bytecode Optimization Pass Framework
 **Current Gap**: Bytecode is emitted directly, no optimization.
 **Architectural Solution**: Add optimization pipeline:
 ```typescript
 type Optimizer = (bytecode: Bytecode) => Bytecode
 // Framework for composable optimization passes
 class BytecodeOptimizer {
  passes: Optimizer[] = []
  add(pass: Optimizer): this {
    this.passes.push(pass)
    return this
  }
  optimize(bytecode: Bytecode): Bytecode {
    return this.passes.reduce((bc, pass) => pass(bc), bytecode)
  }
 }
 // Example passes:
 const optimizer = new BytecodeOptimizer()
  .add(constantFolding)      // PUSH 2; PUSH 3; ADD → PUSH 5
  .add(deadCodeElimination)  // Remove unreachable code after HALT/RETURN
  .add(jumpChaining)         // JUMP .a → .a: JUMP .b → JUMP .b directly
  .add(peepholeOptimization) // DUP; POP → (nothing)
 ```
 **Benefits**:
 - Faster execution without changing compiler
 - Can add passes without modifying VM
 - Composable and testable
 - Enables aggressive optimizations (inlining, constant folding, etc.)
 ---
 ## 6. Value Memory Management Architecture
 **Current Issue**: No tracking of memory usage, no GC hooks, unbounded growth.
 **Architectural Solution**: Add memory management layer:
 ```typescript
 class MemoryManager {
  allocatedBytes: number = 0
  maxBytes?: number
  allocateValue(value: Value): Value {
    const size = this.sizeOf(value)
    if (this.maxBytes && this.allocatedBytes + size > this.maxBytes) {
      throw new Error('Out of memory')
    }
    this.allocatedBytes += size
    return value
  }
  sizeOf(value: Value): number {
    // Estimate memory footprint
  }
  // Hook for custom GC
  gc?: () => void
 }
 class VM {
  memory: MemoryManager
  // All value-creating operations check memory
  push(value: Value) {
    this.memory.allocateValue(value)
    this.stack.push(value)
  }
 }
 ```
 **Benefits**:
 - Memory limits for sandboxing
 - Memory profiling
 - Custom GC strategies
 - Prevents runaway memory usage
 ---
 ## 7. Instruction Profiler Architecture
 **Current Gap**: No way to identify performance bottlenecks in bytecode.
 **Architectural Solution**: Add instrumentation layer:
 ```typescript
 class Profiler {
  instructionCounts: Map<number, number> = new Map()
  instructionTime: Map<number, number> = new Map()
  hotFunctions: Map<number, FunctionProfile> = new Map()
  recordInstruction(pc: number, duration: number) {
    this.instructionCounts.set(pc, (this.instructionCounts.get(pc) || 0) + 1)
    this.instructionTime.set(pc, (this.instructionTime.get(pc) || 0) + duration)
  }
  getHotSpots(): HotSpot[] {
    // Identify most-executed instructions
  }
  generateReport(): ProfileReport {
    // Human-readable performance report
  }
 }
 class VM {
  profiler?: Profiler
  async execute(instruction: Instruction) {
    const start = performance.now()
    // ... execute ...
    const duration = performance.now() - start
    this.profiler?.recordInstruction(this.pc, duration)
  }
 }
 ```
 **Benefits**:
 - Identify hot loops and functions
 - Guide optimization efforts
 - Measure impact of changes
 - Can feed into JIT compiler (future)
 ---
 ## 8. Standard Library Plugin Architecture
 **Current Issue**: Native functions registered manually, no standard library structure.
 **Architectural Solution**: Module-based native libraries:
 ```typescript
 interface NativeModule {
  name: string
  exports: Record<string, any>
  init?(vm: VM): void
 }
 class VM {
  modules: Map<string, NativeModule> = new Map()
  registerModule(module: NativeModule) {
    this.modules.set(module.name, module)
    module.init?.(this)
    // Auto-register exports to global scope
    for (const [name, value] of Object.entries(module.exports)) {
      this.set(name, value)
    }
  }
  loadModule(name: string): NativeModule {
    return this.modules.get(name) || throw new Error(`Module ${name} not found`)
  }
 }
 // Example usage:
 const mathModule: NativeModule = {
  name: 'math',
  exports: {
    sin: Math.sin,
    cos: Math.cos,
    sqrt: Math.sqrt,
    PI: Math.PI
  }
 }
 vm.registerModule(mathModule)
 ```
 **Benefits**:
 - Organized standard library
 - Lazy loading of modules
 - Third-party plugin system
 - Clear namespace boundaries
 ---
 ## 9. Streaming Bytecode Execution
 **Current Limitation**: Must load entire bytecode before execution.
 **Architectural Solution**: Incremental bytecode loading:
 ```typescript
 class StreamingBytecode {
  chunks: BytecodeChunk[] = []
  append(chunk: BytecodeChunk) {
    // Remap addresses, merge constants
    this.chunks.push(chunk)
  }
  getInstruction(pc: number): Instruction | undefined {
    // Resolve across chunks
  }
 }
 class VM {
  async runStreaming(stream: ReadableStream<BytecodeChunk>) {
    for await (const chunk of stream) {
      this.bytecode.append(chunk)
      await this.continue()  // Execute new chunk
    }
  }
 }
 ```
 **Benefits**:
 - Execute before full load (faster startup)
 - Network streaming of bytecode
 - Incremental compilation
 - Better REPL experience
 ---
 ## 10. Type Annotation System (Optional Runtime Types)
 **Current Gap**: All values dynamically typed, no way to enforce types.
 **Architectural Solution**: Optional type metadata:
 ```typescript
 type TypedValue = Value & {
  typeAnnotation?: TypeAnnotation
 }
 type TypeAnnotation =
  | { kind: 'number' }
  | { kind: 'string' }
  | { kind: 'array', elementType?: TypeAnnotation }
  | { kind: 'dict', valueType?: TypeAnnotation }
  | { kind: 'function', params: TypeAnnotation[], return: TypeAnnotation }
 // New opcodes: TYPE_CHECK, TYPE_ASSERT
 // Functions can declare parameter types:
 MAKE_FUNCTION (x:number y:string) .body
 ```
 **Benefits**:
 - Catch type errors earlier
 - Self-documenting code
 - Enables static analysis tools
 - Optional (doesn't break existing code)
 - Can enable optimizations (known number type → skip toNumber())
 ---
 ## 11. VM State Serialization
 **Current Gap**: Can't save/restore VM execution state.
 **Architectural Solution**: Serializable VM state:
 ```typescript
 class VM {
  serialize(): SerializedState {
    return {
      instructions: this.instructions,
      constants: this.constants,
      pc: this.pc,
      stack: this.stack.map(serializeValue),
      callStack: this.callStack.map(serializeFrame),
      scope: serializeScope(this.scope),
      handlers: this.handlers
    }
  }
  static deserialize(state: SerializedState): VM {
    const vm = new VM(/* ... */)
    vm.restore(state)
    return vm
  }
 }
 ```
 **Benefits**:
 - Save/restore execution state
 - Distributed computing (send state to workers)
 - Crash recovery
 - Time-travel debugging
 - Checkpoint/restart
 ---
 ## 12. Async Iterator Support
 **Current Gap**: Iterators work via break, but no async iteration.
 **Architectural Solution**: First-class async iteration:
 ```typescript
 // New value type:
 type Value = ... | { type: 'async_iterator', value: AsyncIterableIterator<Value> }
 // New opcodes: MAKE_ASYNC_ITERATOR, AWAIT_NEXT, YIELD_ASYNC
 // Pattern:
 for_await (item in asyncIterable) {
  // Compiles to AWAIT_NEXT loop
 }
 ```
 **Benefits**:
 - Stream processing
 - Async I/O without blocking
 - Natural async patterns
 - Matches JavaScript async iterators
 ---
 ## Priority Recommendations
 ### Tier 1 (Highest Impact):
 1. **Source Map Integration** - Critical for usability
 2. **Module System** - Essential for scaling beyond toy programs
 3. **Scope Resolution Optimization** - Performance multiplier
 ### Tier 2 (High Value):
 4. **Debugger Hook Architecture** - Developer experience game-changer
 5. **Standard Library Plugin Architecture** - Enables ecosystem
 6. **Bytecode Optimization Framework** - Performance without complexity
 ### Tier 3 (Nice to Have):
 7. **Instruction Profiler** - Guides future optimization
 8. **Memory Management** - Important for production use
 9. **VM State Serialization** - Enables advanced use cases
 ### Tier 4 (Future/Experimental):
 10. **Type Annotations** - Optional, doesn't break existing code
 11. **Streaming Bytecode** - Mostly useful for large programs
 12. **Async Iterators** - Specialized use case
 ---
 ## Design Principles
 These improvements focus on:
 - **Performance** (scope optimization, bytecode optimization)
 - **Developer Experience** (source maps, debugger, profiler)
 - **Scalability** (modules, standard library architecture)
 - **Production Readiness** (memory management, serialization)
 All ideas maintain ReefVM's core design philosophy of simplicity, orthogonality, and explicit behavior.
--- a/README.md
+++ b/README.md
@ -44,14 +44,11 @@ Commands: `clear`, `reset`, `exit`.
 - Variadic functions with positional rest parameters (`...rest`)
 - Named arguments (named) that collect unmatched named args into a dict (`@named`)
 - Mixed positional and named arguments with proper priority binding
 - Default parameter values with null-triggering: passing `null` explicitly uses the default value
 - Tail call optimization with unbounded recursion (10,000+ iterations without stack overflow)
 - Exception handling (PUSH_TRY, PUSH_FINALLY, POP_TRY, THROW) with nested try/finally blocks and call stack unwinding
 - Native function interop with auto-wrapping for native TypeScript types
 - Native functions stored in scope, called via LOAD + CALL
 - Native functions support `atXxx` parameters (e.g., `atOptions`) to collect unmatched named args
 - Pass functions directly to `run(bytecode, { fnName: fn })` or `new VM(bytecode, { fnName: fn })`
 - Call Reef functions from TypeScript with `vm.call(name, ...args)` with automatic type conversion
 ## Design Decisions
@ -61,4 +58,3 @@ Commands: `clear`, `reset`, `exit`.
 - Variadic parameters: Functions can collect remaining positional arguments into an array using `...rest` syntax
 - Named parameters: Functions can collect unmatched named arguments into a dict using `@named` syntax
 - Argument binding priority: Named args bind to regular params first, with unmatched ones going to `@named`
 - Null triggers defaults: Passing `null` to a parameter with a default value explicitly uses that default (applies to both ReefVM and native functions)
--- a/SPEC.md
+++ b/SPEC.md
@ -138,24 +138,6 @@ type ExceptionHandler = {
 **Effect**: Duplicate top of stack
 **Stack**: [value] → [value, value]
 #### SWAP
 **Operand**: None
 **Effect**: Swap the top two values on the stack
 **Stack**: [value1, value2] → [value2, value1]
 #### TYPE
 **Operand**: None
 **Effect**: Pop value from stack, push its type as a string
 **Stack**: [value] → [typeString]
 Returns the type of a value as a string. 
 **Example**:
 ```
 PUSH 42
 TYPE              ; Pushes "number"
 ```
 ### Variable Operations
 #### LOAD
@ -197,29 +179,7 @@ All arithmetic operations pop two values, perform operation, push result as numb
 #### ADD
 **Stack**: [a, b] → [a + b]
-
+**Note**: Only for numbers (use separate string concat if needed)
 Performs different operations depending on operand types:
 - If either operand is a string, converts both to strings and concatenates
 - Else if both operands are arrays, concatenates the arrays
 - Else if both operands are dicts, merges them (b's keys overwrite a's keys on conflict)
 - Else if both operands are numbers, performs numeric addition
 - Otherwise, throws an error
 **Examples**:
 - `5 + 3` → `8` (numeric addition)
 - `"hello" + " world"` → `"hello world"` (string concatenation)
 - `"count: " + 42` → `"count: 42"` (string concatenation)
 - `100 + " items"` → `"100 items"` (string concatenation)
 - `[1, 2, 3] + [4]` → `[1, 2, 3, 4]` (array concatenation)
 - `[1, 2] + [3, 4]` → `[1, 2, 3, 4]` (array concatenation)
 - `{a: 1} + {b: 2}` → `{a: 1, b: 2}` (dict merge)
 - `{a: 1, b: 2} + {b: 99}` → `{a: 1, b: 99}` (dict merge, b overwrites)
 **Invalid operations** (throw errors):
 - `true + false` → Error
 - `null + 5` → Error
 - `[1] + 5` → Error
 - `{a: 1} + 5` → Error
 #### SUB
 **Stack**: [a, b] → [a - b]
@ -233,62 +193,6 @@ Performs different operations depending on operand types:
 #### MOD
 **Stack**: [a, b] → [a % b]
 ### Bitwise Operations
 All bitwise operations coerce operands to 32-bit signed integers, perform the operation, and push the result as a number.
 #### BIT_AND
 **Operand**: None
 **Stack**: [a, b] → [a & b]
 Performs bitwise AND operation. Both operands are coerced to 32-bit signed integers.
 **Example**: `5 & 3` → `1` (binary: `0101 & 0011` → `0001`)
 #### BIT_OR
 **Operand**: None
 **Stack**: [a, b] → [a | b]
 Performs bitwise OR operation. Both operands are coerced to 32-bit signed integers.
 **Example**: `5 | 3` → `7` (binary: `0101 | 0011` → `0111`)
 #### BIT_XOR
 **Operand**: None
 **Stack**: [a, b] → [a ^ b]
 Performs bitwise XOR (exclusive OR) operation. Both operands are coerced to 32-bit signed integers.
 **Example**: `5 ^ 3` → `6` (binary: `0101 ^ 0011` → `0110`)
 #### BIT_SHL
 **Operand**: None
 **Stack**: [a, b] → [a << b]
 Performs left shift operation. Left operand is coerced to 32-bit signed integer, right operand determines shift amount (masked to 0-31).
 **Example**: `5 << 2` → `20` (binary: `0101` shifted left 2 positions → `10100`)
 #### BIT_SHR
 **Operand**: None
 **Stack**: [a, b] → [a >> b]
 Performs sign-preserving right shift operation. Left operand is coerced to 32-bit signed integer, right operand determines shift amount (masked to 0-31). The sign bit is preserved (arithmetic shift).
 **Example**:
 - `20 >> 2` → `5` (binary: `10100` shifted right 2 positions → `0101`)
 - `-20 >> 2` → `-5` (sign bit preserved)
 #### BIT_USHR
 **Operand**: None
 **Stack**: [a, b] → [a >>> b]
 Performs zero-fill right shift operation. Left operand is coerced to 32-bit signed integer, right operand determines shift amount (masked to 0-31). Zeros are shifted in from the left (logical shift).
 **Example**:
 - `-1 >>> 1` → `2147483647` (all bits shift right, zero fills from left)
 - `-8 >>> 1` → `2147483644`
 ### Comparison Operations
 All comparison operations pop two values, compare, push boolean result.
@ -327,45 +231,39 @@ All comparison operations pop two values, compare, push boolean result.
 ```
 <evaluate left>
 DUP
-JUMP_IF_FALSE .end
+JUMP_IF_FALSE #2    # skip POP and <evaluate right>
 POP
 <evaluate right>
-.end:
+end:
 ```
 **OR pattern** (short-circuits if left side is true):
 ```
 <evaluate left>
 DUP
-JUMP_IF_TRUE .end
+JUMP_IF_TRUE #2     # skip POP and <evaluate right>
 POP
 <evaluate right>
-.end:
+end:
 ```
 ### Control Flow
 #### JUMP
-**Operand**: Label (string)
+**Operand**: Offset (number)
-**Effect**: Jump to the specified label
+**Effect**: Add offset to PC (relative jump)
 **Stack**: No change
 **Note**: JUMP only accepts label operands (`.label`), not numeric offsets. The VM resolves labels to relative offsets internally.
 #### JUMP_IF_FALSE
-**Operand**: Label (string)
+**Operand**: Offset (number)
-**Effect**: If top of stack is falsy, jump to the specified label
+**Effect**: If top of stack is falsy, add offset to PC (relative jump)
 **Stack**: [condition] → []
 **Note**: JUMP_IF_FALSE only accepts label operands (`.label`), not numeric offsets.
 #### JUMP_IF_TRUE
-**Operand**: Label (string)
+**Operand**: Offset (number)
-**Effect**: If top of stack is truthy, jump to the specified label
+**Effect**: If top of stack is truthy, add offset to PC (relative jump)
 **Stack**: [condition] → []
 **Note**: JUMP_IF_TRUE only accepts label operands (`.label`), not numeric offsets.
 #### BREAK
 **Operand**: None
 **Effect**: Unwind call stack until frame with `isBreakTarget = true`, resume there
@ -480,19 +378,11 @@ The created function captures `currentScope` as its `parentScope`.
 3. Default value (if defined)
 4. Null
 **Null Value Semantics**:
 - Passing `null` as an argument explicitly triggers the default value (if one exists)
 - This allows callers to "opt-in" to defaults even when providing arguments positionally
 - If no default exists, `null` is bound as-is
 - This applies to both ReefVM functions and native TypeScript functions
 - Example: `fn(null, 20)` where `fn(x=10, y)` binds `x=10` (default triggered), `y=20`
 **Named Args Handling**:
 - Named args that match fixed parameter names are bound to those params
 - If the function has `named: true`, remaining named args (that don't match any fixed param) are collected into the last parameter as a dict
 - This allows flexible calling: `fn(x=10, y=20, extra=30)` where `extra` goes to the named args dict
 - **Native functions support named arguments** - parameter names are extracted from the function signature at call time
 - Passing `null` via named args also triggers defaults: `fn(x=null)` triggers `x`'s default
 **Errors**: Throws if top of stack is not a function (or native function)
@ -732,7 +622,7 @@ const vm = new VM(bytecode, {
 })
 // Or after construction:
-vm.set('multiply', (a: number, b: number) => a * b)
+vm.registerFunction('multiply', (a: number, b: number) => a * b)
 ```
 **Usage in Bytecode**:
@ -747,9 +637,9 @@ CALL              ; Call it like any other function
 **Native Function Types**:
-1. **Auto-wrapped functions** (via `vm.set()`): Accept and return native TypeScript types (number, string, boolean, array, object, etc.). The VM automatically converts between Value types and native types.
+1. **Auto-wrapped functions** (via `registerFunction`): Accept and return native TypeScript types (number, string, boolean, array, object, etc.). The VM automatically converts between Value types and native types.
-2. **Value-based functions** (via `vm.setValueFunction()`): Accept and return `Value` types directly for full control over type handling.
+2. **Value-based functions** (via `registerValueFunction`): Accept and return `Value` types directly for full control over type handling.
 **Auto-Wrapping Behavior**:
 - Parameters: `Value` → native type (number, string, boolean, array, object, null, RegExp)
@ -765,27 +655,27 @@ CALL              ; Call it like any other function
 **Examples**:
 ```typescript
 // Auto-wrapped native types
-vm.set('add', (a: number, b: number) => a + b)
+vm.registerFunction('add', (a: number, b: number) => a + b)
-vm.set('greet', (name: string) => `Hello, ${name}!`)
+vm.registerFunction('greet', (name: string) => `Hello, ${name}!`)
-vm.set('range', (n: number) => Array.from({ length: n }, (_, i) => i))
+vm.registerFunction('range', (n: number) => Array.from({ length: n }, (_, i) => i))
 // With defaults
-vm.set('greet', (name: string, greeting = 'Hello') => {
+vm.registerFunction('greet', (name: string, greeting = 'Hello') => {
  return `${greeting}, ${name}!`
 })
 // Variadic functions
-vm.set('sum', (...nums: number[]) => {
+vm.registerFunction('sum', (...nums: number[]) => {
  return nums.reduce((acc, n) => acc + n, 0)
 })
 // Value-based for custom logic
-vm.setValueFunction('customOp', (a: Value, b: Value): Value => {
+vm.registerValueFunction('customOp', (a: Value, b: Value): Value => {
  return { type: 'number', value: toNumber(a) + toNumber(b) }
 })
 // Async functions
-vm.set('fetchData', async (url: string) => {
+vm.registerFunction('fetchData', async (url: string) => {
  const response = await fetch(url)
  return response.json()
 })
@ -820,16 +710,14 @@ CALL              ; → "Hi, Bob!"
 ## Label Syntax
-The bytecode format requires labels for control flow jumps:
+The bytecode format supports labels for improved readability:
 **Label Definition**: `.label_name:` marks an instruction position
 **Label Reference**: `.label_name` in operands (e.g., `JUMP .loop_start`)
-Labels are resolved to relative PC offsets during bytecode compilation. All JUMP instructions (`JUMP`, `JUMP_IF_FALSE`, `JUMP_IF_TRUE`) require label operands.
+Labels are resolved to numeric offsets during parsing. The original numeric offset syntax (`#N`) is still supported for backwards compatibility.
-**Note**: Exception handling instructions (`PUSH_TRY`, `PUSH_FINALLY`) and function definitions (`MAKE_FUNCTION`) can use either labels or absolute instruction indices (`#N`).
+Example with labels:
 Example:
 ```
 JUMP .skip
 .middle:
@ -840,6 +728,15 @@ JUMP .skip
  HALT
 ```
 Equivalent with numeric offsets:
 ```
 JUMP #2
 PUSH 999
 HALT
 PUSH 42
 HALT
 ```
 ## Common Bytecode Patterns
 ### If-Else Statement
@ -915,29 +812,6 @@ PUSH 1                # namedCount
 CALL
 ```
 ### Null Triggering Default Values
 ```
 # Function: greet(name='Guest', greeting='Hello')
 MAKE_FUNCTION (name='Guest' greeting='Hello') .greet_body
 STORE 'greet'
 JUMP .main
 .greet_body:
  LOAD 'greeting'
  PUSH ', '
  ADD
  LOAD 'name'
  ADD
  RETURN
 .main:
  # Call with null for first param - triggers default
  LOAD 'greet'
  PUSH null            # name will use default 'Guest'
  PUSH 'Hi'            # greeting='Hi' (provided)
  PUSH 2               # positionalCount
  PUSH 0               # namedCount
  CALL                 # Returns "Hi, Guest"
 ```
 ### Tail Recursive Function
 ```
 MAKE_FUNCTION (n acc) .factorial_body
@ -1038,10 +912,10 @@ const vm = new VM(bytecode, {
 })
 // Or register after construction
-vm.set('multiply', (a: number, b: number) => a * b)
+vm.registerFunction('multiply', (a: number, b: number) => a * b)
 // Or use Value-based functions
-vm.setValueFunction('customOp', (a: Value, b: Value): Value => {
+vm.registerValueFunction('customOp', (a: Value, b: Value): Value => {
  return { type: 'number', value: toNumber(a) + toNumber(b) }
 })
--- a/bin/debug
+++ b/bin/debug
@ -104,8 +104,6 @@ function formatValue(value: Value): string {
  } else if (value.type === 'function') {
    const params = value.params.join(', ')
    return `${colors.dim}<fn(${params})>${colors.reset}`
  } else if (value.type === 'native') {
    return `${colors.dim}<native>${colors.reset}`
  }
  return String(value)
 }
--- a/bin/repl
+++ b/bin/repl
@ -38,8 +38,6 @@ function formatValue(value: Value): string {
  } else if (value.type === 'function') {
    const params = value.params.join(', ')
    return `${colors.dim}<fn(${params})>${colors.reset}`
  } else if (value.type === 'native') {
    return `${colors.dim}<native>${colors.reset}`
  }
  return String(value)
 }
--- a/bunfig.toml
+++ b/bunfig.toml
@ -1,2 +0,0 @@
 [test]
 preload = ["./tests/setup.ts"]
--- a/examples/add-with-arrays.ts
+++ b/examples/add-with-arrays.ts
@ -1,116 +0,0 @@
 /**
 * Demonstrates the ADD opcode working with arrays
 *
 * ADD now handles array concatenation:
 * - [1, 2, 3] + [4] === [1, 2, 3, 4]
 * - If both operands are arrays, they are concatenated
 */
 import { toBytecode, run } from "#reef"
 // Basic array concatenation
 const basicConcat = toBytecode([
  ["PUSH", 1],
  ["PUSH", 2],
  ["PUSH", 3],
  ["MAKE_ARRAY", 3],
  ["PUSH", 4],
  ["MAKE_ARRAY", 1],
  ["ADD"],
  ["HALT"]
 ])
 console.log('Basic array concatenation ([1, 2, 3] + [4]):')
 const result1 = await run(basicConcat)
 console.log(result1)
 // Output: { type: 'array', value: [1, 2, 3, 4] }
 // Concatenate two multi-element arrays
 const multiConcat = toBytecode([
  ["PUSH", 1],
  ["PUSH", 2],
  ["MAKE_ARRAY", 2],
  ["PUSH", 3],
  ["PUSH", 4],
  ["MAKE_ARRAY", 2],
  ["ADD"],
  ["HALT"]
 ])
 console.log('\nConcatenate two arrays ([1, 2] + [3, 4]):')
 const result2 = await run(multiConcat)
 console.log(result2)
 // Output: { type: 'array', value: [1, 2, 3, 4] }
 // Concatenate multiple arrays in sequence
 const multipleConcat = toBytecode([
  ["PUSH", 1],
  ["MAKE_ARRAY", 1],
  ["PUSH", 2],
  ["MAKE_ARRAY", 1],
  ["ADD"],
  ["PUSH", 3],
  ["MAKE_ARRAY", 1],
  ["ADD"],
  ["PUSH", 4],
  ["MAKE_ARRAY", 1],
  ["ADD"],
  ["HALT"]
 ])
 console.log('\nMultiple concatenations ([1] + [2] + [3] + [4]):')
 const result3 = await run(multipleConcat)
 console.log(result3)
 // Output: { type: 'array', value: [1, 2, 3, 4] }
 // Concatenate arrays with mixed types
 const mixedTypes = toBytecode([
  ["PUSH", 1],
  ["PUSH", "hello"],
  ["MAKE_ARRAY", 2],
  ["PUSH", true],
  ["PUSH", null],
  ["MAKE_ARRAY", 2],
  ["ADD"],
  ["HALT"]
 ])
 console.log('\nConcatenate arrays with mixed types ([1, "hello"] + [true, null]):')
 const result4 = await run(mixedTypes)
 console.log(result4)
 // Output: { type: 'array', value: [1, "hello", true, null] }
 // Concatenate empty array with non-empty
 const emptyConcat = toBytecode([
  ["MAKE_ARRAY", 0],
  ["PUSH", 1],
  ["PUSH", 2],
  ["PUSH", 3],
  ["MAKE_ARRAY", 3],
  ["ADD"],
  ["HALT"]
 ])
 console.log('\nConcatenate empty array with [1, 2, 3] ([] + [1, 2, 3]):')
 const result5 = await run(emptyConcat)
 console.log(result5)
 // Output: { type: 'array', value: [1, 2, 3] }
 // Nested arrays
 const nestedConcat = toBytecode([
  ["PUSH", 1],
  ["PUSH", 2],
  ["MAKE_ARRAY", 2],
  ["MAKE_ARRAY", 1],
  ["PUSH", 3],
  ["PUSH", 4],
  ["MAKE_ARRAY", 2],
  ["MAKE_ARRAY", 1],
  ["ADD"],
  ["HALT"]
 ])
 console.log('\nConcatenate nested arrays ([[1, 2]] + [[3, 4]]):')
 const result6 = await run(nestedConcat)
 console.log(result6)
 // Output: { type: 'array', value: [[1, 2], [3, 4]] }
--- a/examples/add-with-dicts.ts
+++ b/examples/add-with-dicts.ts
@ -1,158 +0,0 @@
 /**
 * Demonstrates the ADD opcode working with dicts
 *
 * ADD now handles dict merging:
 * - {a: 1} + {b: 2} === {a: 1, b: 2}
 * - If both operands are dicts, they are merged
 * - Keys from the second dict overwrite keys from the first on conflict
 */
 import { toBytecode, run } from "#reef"
 // Basic dict merge
 const basicMerge = toBytecode([
  ["PUSH", "a"],
  ["PUSH", 1],
  ["MAKE_DICT", 1],
  ["PUSH", "b"],
  ["PUSH", 2],
  ["MAKE_DICT", 1],
  ["ADD"],
  ["HALT"]
 ])
 console.log('Basic dict merge ({a: 1} + {b: 2}):')
 const result1 = await run(basicMerge)
 console.log(result1)
 // Output: { type: 'dict', value: Map { a: 1, b: 2 } }
 // Merge with overlapping keys
 const overlapMerge = toBytecode([
  ["PUSH", "a"],
  ["PUSH", 1],
  ["PUSH", "b"],
  ["PUSH", 2],
  ["MAKE_DICT", 2],
  ["PUSH", "b"],
  ["PUSH", 99],
  ["PUSH", "c"],
  ["PUSH", 3],
  ["MAKE_DICT", 2],
  ["ADD"],
  ["HALT"]
 ])
 console.log('\nMerge with overlapping keys ({a: 1, b: 2} + {b: 99, c: 3}):')
 const result2 = await run(overlapMerge)
 console.log(result2)
 console.log('Note: b is overwritten from 2 to 99')
 // Output: { type: 'dict', value: Map { a: 1, b: 99, c: 3 } }
 // Merge multiple dicts in sequence
 const multipleMerge = toBytecode([
  ["PUSH", "a"],
  ["PUSH", 1],
  ["MAKE_DICT", 1],
  ["PUSH", "b"],
  ["PUSH", 2],
  ["MAKE_DICT", 1],
  ["ADD"],
  ["PUSH", "c"],
  ["PUSH", 3],
  ["MAKE_DICT", 1],
  ["ADD"],
  ["PUSH", "d"],
  ["PUSH", 4],
  ["MAKE_DICT", 1],
  ["ADD"],
  ["HALT"]
 ])
 console.log('\nMultiple merges ({a: 1} + {b: 2} + {c: 3} + {d: 4}):')
 const result3 = await run(multipleMerge)
 console.log(result3)
 // Output: { type: 'dict', value: Map { a: 1, b: 2, c: 3, d: 4 } }
 // Merge dicts with different value types
 const mixedTypes = toBytecode([
  ["PUSH", "num"],
  ["PUSH", 42],
  ["PUSH", "str"],
  ["PUSH", "hello"],
  ["MAKE_DICT", 2],
  ["PUSH", "bool"],
  ["PUSH", true],
  ["PUSH", "null"],
  ["PUSH", null],
  ["MAKE_DICT", 2],
  ["ADD"],
  ["HALT"]
 ])
 console.log('\nMerge dicts with different types ({num: 42, str: "hello"} + {bool: true, null: null}):')
 const result4 = await run(mixedTypes)
 console.log(result4)
 // Output: { type: 'dict', value: Map { num: 42, str: 'hello', bool: true, null: null } }
 // Merge empty dict with non-empty
 const emptyMerge = toBytecode([
  ["MAKE_DICT", 0],
  ["PUSH", "x"],
  ["PUSH", 100],
  ["PUSH", "y"],
  ["PUSH", 200],
  ["MAKE_DICT", 2],
  ["ADD"],
  ["HALT"]
 ])
 console.log('\nMerge empty dict with {x: 100, y: 200} ({} + {x: 100, y: 200}):')
 const result5 = await run(emptyMerge)
 console.log(result5)
 // Output: { type: 'dict', value: Map { x: 100, y: 200 } }
 // Merge dicts with nested structures
 const nestedMerge = toBytecode([
  ["PUSH", "data"],
  ["PUSH", 1],
  ["PUSH", 2],
  ["MAKE_ARRAY", 2],
  ["MAKE_DICT", 1],
  ["PUSH", "config"],
  ["PUSH", "debug"],
  ["PUSH", true],
  ["MAKE_DICT", 1],
  ["MAKE_DICT", 1],
  ["ADD"],
  ["HALT"]
 ])
 console.log('\nMerge dicts with nested structures:')
 const result6 = await run(nestedMerge)
 console.log(result6)
 // Output: { type: 'dict', value: Map { data: [1, 2], config: { debug: true } } }
 // Building configuration objects
 const configBuild = toBytecode([
  // Default config
  ["PUSH", "debug"],
  ["PUSH", false],
  ["PUSH", "port"],
  ["PUSH", 3000],
  ["PUSH", "host"],
  ["PUSH", "localhost"],
  ["MAKE_DICT", 3],
  // Override with user config
  ["PUSH", "debug"],
  ["PUSH", true],
  ["PUSH", "port"],
  ["PUSH", 8080],
  ["MAKE_DICT", 2],
  ["ADD"],
  ["HALT"]
 ])
 console.log('\nBuilding config (defaults + overrides):')
 const result7 = await run(configBuild)
 console.log(result7)
 // Output: { type: 'dict', value: Map { debug: true, port: 8080, host: 'localhost' } }
--- a/examples/add-with-strings.ts
+++ b/examples/add-with-strings.ts
@ -1,73 +0,0 @@
 /**
 * Demonstrates the ADD opcode working with both numbers and strings
 *
 * ADD now behaves like JavaScript's + operator:
 * - If either operand is a string, it does string concatenation
 * - Otherwise, it does numeric addition
 */
 import { toBytecode, run } from "#reef"
 // Numeric addition
 const numericAdd = toBytecode(`
  PUSH 10
  PUSH 5
  ADD
  HALT
 `)
 console.log('Numeric addition (10 + 5):')
 console.log(await run(numericAdd))
 // Output: { type: 'number', value: 15 }
 // String concatenation
 const stringConcat = toBytecode(`
  PUSH "hello"
  PUSH " world"
  ADD
  HALT
 `)
 console.log('\nString concatenation ("hello" + " world"):')
 console.log(await run(stringConcat))
 // Output: { type: 'string', value: 'hello world' }
 // Mixed: string + number
 const mixedConcat = toBytecode(`
  PUSH "count: "
  PUSH 42
  ADD
  HALT
 `)
 console.log('\nMixed concatenation ("count: " + 42):')
 console.log(await run(mixedConcat))
 // Output: { type: 'string', value: 'count: 42' }
 // Building a message
 const buildMessage = toBytecode(`
  PUSH "You have "
  PUSH 3
  ADD
  PUSH " new messages"
  ADD
  HALT
 `)
 console.log('\nBuilding a message:')
 console.log(await run(buildMessage))
 // Output: { type: 'string', value: 'You have 3 new messages' }
 // Computing then concatenating
 const computeAndConcat = toBytecode(`
  PUSH "Result: "
  PUSH 10
  PUSH 5
  ADD
  ADD
  HALT
 `)
 console.log('\nComputing then concatenating ("Result: " + (10 + 5)):')
 console.log(await run(computeAndConcat))
 // Output: { type: 'string', value: 'Result: 15' }
--- a/examples/native.ts
+++ b/examples/native.ts
@ -9,7 +9,7 @@ const bytecode = toBytecode(`
 const vm = new VM(bytecode)
-vm.set('print', (...args: Value[]): Value => {
+vm.registerFunction('print', (...args: Value[]): Value => {
  console.log(...args.map(toString))
  return toNull()
 })
--- a/src/bytecode.ts
+++ b/src/bytecode.ts
@ -16,15 +16,13 @@ export type Constant =
  | Value
  | FunctionDef
-type Atom = RegExp | number | string | boolean | null
+type Atom = number | string | boolean | null
 type InstructionTuple =
  // Stack
  | ["PUSH", Atom]
  | ["POP"]
  | ["DUP"]
  | ["SWAP"]
  | ["TYPE"]
  // Variables
  | ["LOAD", string]
@ -34,9 +32,6 @@ type InstructionTuple =
  // Arithmetic
  | ["ADD"] | ["SUB"] | ["MUL"] | ["DIV"] | ["MOD"]
  // Bitwise
  | ["BIT_AND"] | ["BIT_OR"] | ["BIT_XOR"] | ["BIT_SHL"] | ["BIT_SHR"] | ["BIT_USHR"]
  // Comparison
  | ["EQ"] | ["NEQ"] | ["LT"] | ["GT"] | ["LTE"] | ["GTE"]
@ -44,9 +39,9 @@ type InstructionTuple =
  | ["NOT"]
  // Control flow
-  | ["JUMP", string]
+  | ["JUMP", string | number]
-  | ["JUMP_IF_FALSE", string]
+  | ["JUMP_IF_FALSE", string | number]
-  | ["JUMP_IF_TRUE", string]
+  | ["JUMP_IF_TRUE", string | number]
  | ["BREAK"]
  // Exception handling
@ -56,7 +51,7 @@ type InstructionTuple =
  | ["THROW"]
  // Functions
-  | ["MAKE_FUNCTION", string[], string]
+  | ["MAKE_FUNCTION", string[], string | number]
  | ["CALL"]
  | ["TAIL_CALL"]
  | ["RETURN"]
@ -88,6 +83,30 @@ type LabelDefinition = [string] // Just ".label_name:"
 export type ProgramItem = InstructionTuple | LabelDefinition
 //
 // Parse bytecode from human-readable string format.
 // Operand types are determined by prefix/literal:
 //   #42      -> immediate number (e.g., JUMP #5, MAKE_ARRAY #3)
 //   .label   -> label reference (e.g., JUMP .loop_start, MAKE_FUNCTION (x y) .body)
 //   name     -> variable/function name (e.g., LOAD x, LOAD_NATIVE add)
 //   42       -> number constant (e.g., PUSH 42)
 //   "str"    -> string constant (e.g., PUSH "hello")
 //   'str'    -> string constant (e.g., PUSH 'hello')
 //   true     -> boolean constant (e.g., PUSH true)
 //   false    -> boolean constant (e.g., PUSH false)
 //   null     -> null constant (e.g., PUSH null)
 //
 // Labels:
 //   .label_name:   -> label definition (marks current instruction position)
 //
 // Function definitions:
 //   MAKE_FUNCTION (x y) #7           -> basic function (numeric offset)
 //   MAKE_FUNCTION (x y) .body        -> basic function (label reference)
 //   MAKE_FUNCTION (x y=42) #7        -> with defaults
 //   MAKE_FUNCTION (x ...rest) #7     -> variadic
 //   MAKE_FUNCTION (x @named) #7      -> named
 //
 function parseFunctionParams(paramStr: string, constants: Constant[]): {
  params: string[]
  defaults: Record<string, number>
@ -349,29 +368,6 @@ function toBytecodeFromArray(program: ProgramItem[]): Bytecode /* throws */ {
  }
 }
 ////
 // Parse bytecode from human-readable string format.
 // Operand types are determined by prefix/literal:
 //   #42      -> immediate number (e.g., JUMP #5, MAKE_ARRAY #3)
 //   .label   -> label reference (e.g., JUMP .loop_start, MAKE_FUNCTION (x y) .body)
 //   name     -> variable/function name (e.g., LOAD x, LOAD_NATIVE add)
 //   42       -> number constant (e.g., PUSH 42)
 //   "str"    -> string constant (e.g., PUSH "hello")
 //   'str'    -> string constant (e.g., PUSH 'hello')
 //   true     -> boolean constant (e.g., PUSH true)
 //   false    -> boolean constant (e.g., PUSH false)
 //   null     -> null constant (e.g., PUSH null)
 //
 // Labels:
 //   .label_name:   -> label definition (marks current instruction position)
 //
 // Function definitions:
 //   MAKE_FUNCTION (x y) #7           -> basic function (numeric offset)
 //   MAKE_FUNCTION (x y) .body        -> basic function (label reference)
 //   MAKE_FUNCTION (x y=42) #7        -> with defaults
 //   MAKE_FUNCTION (x ...rest) #7     -> variadic
 //   MAKE_FUNCTION (x @named) #7      -> named
 function toBytecodeFromString(str: string): Bytecode /* throws */ {
  const lines = str.trim().split("\n")
@ -390,7 +386,7 @@ function toBytecodeFromString(str: string): Bytecode /* throws */ {
    if (!trimmed) continue
    // Check for label definition (.label_name:)
-    if (/^\.[a-zA-Z_][a-zA-Z0-9_.]*:$/.test(trimmed)) {
+    if (/^\.[a-zA-Z_][a-zA-Z0-9_]*:$/.test(trimmed)) {
      const labelName = trimmed.slice(1, -1)
      labels.set(labelName, cleanLines.length)
      continue
--- a/src/function.ts
+++ b/src/function.ts
@ -1,5 +1,4 @@
 import { type Value, type NativeFunction, fromValue, toValue } from "./value"
 import { VM } from "./vm"
 export type ParamInfo = {
  params: string[]
@ -10,13 +9,11 @@ export type ParamInfo = {
 const WRAPPED_MARKER = Symbol('reef-wrapped')
-export function wrapNative(vm: VM, fn: Function): (this: VM, ...args: Value[]) => Promise<Value> {
+export function wrapNative(fn: Function): (...args: Value[]) => Promise<Value> {
-  if ((fn as any).raw) return fn as (this: VM, ...args: Value[]) => Promise<Value>
+  const wrapped = async (...values: Value[]) => {
-
+    const nativeArgs = values.map(fromValue)
-  const wrapped = async function (this: VM, ...values: Value[]) {
+    const result = await fn(...nativeArgs)
-    const nativeArgs = values.map(arg => fromValue(arg, vm))
+    return toValue(result)
    const result = await fn.call(this, ...nativeArgs)
    return toValue(result, this)
  }
  const wrappedObj = wrapped as any
--- a/src/index.ts
+++ b/src/index.ts
@ -1,17 +1,14 @@
 import type { Bytecode } from "./bytecode"
-import type { Value } from "./value"
+import { type Value } from "./value"
 import { VM } from "./vm"
-export async function run(bytecode: Bytecode, globals?: Record<string, any>): Promise<Value> {
+export async function run(bytecode: Bytecode, functions?: Record<string, Function>): Promise<Value> {
-  const vm = new VM(bytecode, globals)
+  const vm = new VM(bytecode, functions)
  return await vm.run()
 }
 export { type Bytecode, toBytecode, type ProgramItem } from "./bytecode"
-export { bytecodeToString } from "./format"
+export { wrapNative } from "./function"
-export { wrapNative, isWrapped, type ParamInfo, extractParamInfo, getOriginalFunction } from "./function"
+export { type Value, toValue, toString, toNumber, fromValue, toNull } from "./value"
 export { OpCode } from "./opcode"
 export { Scope } from "./scope"
 export type { Value, TypeScriptFunction, NativeFunction } from "./value"
 export { isValue, toValue, toString, toNumber, fromValue, toNull, fnFromValue } from "./value"
 export { VM } from "./vm"
 export { bytecodeToString } from "./format"
--- a/src/opcode.ts
+++ b/src/opcode.ts
@ -3,16 +3,12 @@ export enum OpCode {
  PUSH,  // operand: constant index (number) | stack: [] → [value]
  POP,   // operand: none | stack: [value] → []
  DUP,   // operand: none | stack: [value] → [value, value]
  SWAP,  // operand: none | stack: [value1, value2] → [value2, value1]
  // variables
  LOAD,     // operand: variable name (identifier) | stack: [] → [value]
  STORE,    // operand: variable name (identifier) | stack: [value] → []
  TRY_LOAD, // operand: variable name (identifier) | stack: [] → [value] | load a variable (if found) or a string
  // information
  TYPE,      // operand: none | stack: [a] → []
  // math (coerce to number, pop 2, push result)
  ADD,   // operand: none | stack: [a, b] → [a + b]
  SUB,   // operand: none | stack: [a, b] → [a - b]
@ -20,14 +16,6 @@ export enum OpCode {
  DIV,   // operand: none | stack: [a, b] → [a / b]
  MOD,   // operand: none | stack: [a, b] → [a % b]
  // bitwise operations (coerce to 32-bit integers, pop 2, push result)
  BIT_AND,   // operand: none | stack: [a, b] → [a & b]
  BIT_OR,    // operand: none | stack: [a, b] → [a | b]
  BIT_XOR,   // operand: none | stack: [a, b] → [a ^ b]
  BIT_SHL,   // operand: none | stack: [a, b] → [a << b]
  BIT_SHR,   // operand: none | stack: [a, b] → [a >> b] (sign-preserving)
  BIT_USHR,  // operand: none | stack: [a, b] → [a >>> b] (zero-fill)
  // comparison (pop 2, push boolean)
  EQ,    // operand: none | stack: [a, b] → [a == b] (deep equality)
  NEQ,   // operand: none | stack: [a, b] → [a != b]
--- a/src/scope.ts
+++ b/src/scope.ts
@ -30,15 +30,6 @@ export class Scope {
  has(name: string): boolean {
    return this.locals.has(name) || this.parent?.has(name) || false
  }
  vars(): string[] {
    const vars = new Set(this.parent?.vars())
    for (const name of this.locals.keys())
      vars.add(name)
    return [...vars].sort()
  }
 }
--- a/src/validator.ts
+++ b/src/validator.ts
@ -50,19 +50,11 @@ const OPCODES_WITH_OPERANDS = new Set([
 const OPCODES_WITHOUT_OPERANDS = new Set([
  OpCode.POP,
  OpCode.DUP,
  OpCode.SWAP,
  OpCode.TYPE,
  OpCode.ADD,
  OpCode.SUB,
  OpCode.MUL,
  OpCode.DIV,
  OpCode.MOD,
  OpCode.BIT_AND,
  OpCode.BIT_OR,
  OpCode.BIT_XOR,
  OpCode.BIT_SHL,
  OpCode.BIT_SHR,
  OpCode.BIT_USHR,
  OpCode.EQ,
  OpCode.NEQ,
  OpCode.LT,
@ -87,15 +79,11 @@ const OPCODES_WITHOUT_OPERANDS = new Set([
  OpCode.DOT_GET,
 ])
-// JUMP* instructions require labels only (no numeric immediates)
+// immediate = immediate number, eg #5
-const OPCODES_REQUIRING_LABEL = new Set([
+const OPCODES_REQUIRING_IMMEDIATE_OR_LABEL = new Set([
  OpCode.JUMP,
  OpCode.JUMP_IF_FALSE,
  OpCode.JUMP_IF_TRUE,
 ])
 // PUSH_TRY/PUSH_FINALLY still allow immediate or label
 const OPCODES_REQUIRING_IMMEDIATE_OR_LABEL = new Set([
  OpCode.PUSH_TRY,
  OpCode.PUSH_FINALLY,
 ])
@ -201,16 +189,6 @@ export function validateBytecode(source: string): ValidationResult {
    // Validate specific operand formats
    if (operand) {
      if (OPCODES_REQUIRING_LABEL.has(opCode)) {
        if (!operand.startsWith('.')) {
          errors.push({
            line: lineNum,
            message: `${opName} requires label (.label), got: ${operand}`,
          })
          continue
        }
      }
      if (OPCODES_REQUIRING_IMMEDIATE_OR_LABEL.has(opCode)) {
        if (!operand.startsWith('#') && !operand.startsWith('.')) {
          errors.push({
@ -324,11 +302,11 @@ export function validateBytecode(source: string): ValidationResult {
          }
        }
-        // Validate body address (must be a label)
+        // Validate body address
-        if (!bodyAddr!.startsWith('.')) {
+        if (!bodyAddr!.startsWith('.') && !bodyAddr!.startsWith('#')) {
          errors.push({
            line: lineNum,
-            message: `Invalid body address: expected .label, got: ${bodyAddr}`,
+            message: `Invalid body address: expected .label or #offset`,
          })
        }
--- a/src/value.ts
+++ b/src/value.ts
@ -1,12 +1,6 @@
 import { wrapNative, getOriginalFunction } from "./function"
 import { OpCode } from "./opcode"
 import { Scope } from "./scope"
 import { VM } from "./vm"
 export type NativeFunction = (...args: Value[]) => Promise<Value> | Value
 export type TypeScriptFunction = (this: VM, ...args: any[]) => any
 const REEF_FUNCTION = Symbol('__reefFunction')
 const VALUE_TYPES = new Set(['null', 'boolean', 'number', 'string', 'array', 'dict', 'regex', 'native', 'function'])
 export type Value =
  | { type: 'null', value: null }
@ -39,19 +33,15 @@ export type FunctionDef = {
  named: boolean
 }
-export function isValue(v: any): boolean {
+export function toValue(v: any): Value /* throws */ {
  return !!(v && typeof v === 'object' && VALUE_TYPES.has(v.type) && 'value' in v)
 }
 export function toValue(v: any, vm?: VM): Value /* throws */ {
  if (v === null || v === undefined)
    return { type: 'null', value: null }
-  if (isValue(v))
+  if (v && typeof v === 'object' && 'type' in v && 'value' in v)
    return v as Value
  if (Array.isArray(v))
-    return { type: 'array', value: v.map(x => toValue(x, vm)) }
+    return { type: 'array', value: v.map(toValue) }
  if (v instanceof RegExp)
    return { type: 'regex', value: v }
@ -64,38 +54,15 @@ export function toValue(v: any, vm?: VM): Value /* throws */ {
    case 'string':
      return { type: 'string', value: v }
    case 'function':
-      if ((v as any)[REEF_FUNCTION])
+      throw "can't toValue() a js function yet"
        return (v as any)[REEF_FUNCTION]
      let fn = vm ? wrapNative(vm, v) : cantCallFunctionWithoutVM(v)
      return { type: 'native', fn, value: '<function>' }
    case 'object':
      const dict: Dict = new Map()
-      for (const key of Object.keys(v)) dict.set(key, toValue(v[key], vm))
+      for (const key of Object.keys(v)) dict.set(key, toValue(v[key]))
      return { type: 'dict', value: dict }
    default:
-      throw new Error(`can't toValue this: ${v}`)
+      throw `can't toValue this: ${v}`
  }
 }
 function cantCallFunctionWithoutVM(fn: Function) {
  const name = fn.name || '<anonymous>'
  const str = fn.toString().slice(0, 100)
  return (...args: Value[]) => {
    const stack = new Error().stack || ''
    const stackLines = stack.split('\n')
      .slice(1)
      .filter(line => !line.includes('toValue'))
      .map(line => '    ' + line.trim())
      .join('\n')
    throw new Error(
      `can't call function that was converted without a vm\n` +
      `  Function: ${name}\n` +
      `  Source: ${str}${str.length > 100 ? '...' : ''}\n` +
      `  Called from:\n${stackLines}`
    )
  }
 }
@ -187,87 +154,28 @@ export function isEqual(a: Value, b: Value): boolean {
  }
 }
-export function fromValue(v: Value, vm?: VM): any {
+export function fromValue(v: Value): any {
  switch (v.type) {
    case 'null':
      return null
    case 'boolean':
      return v.value
    case 'number':
      return v.value
    case 'string':
      return v.value
    case 'array':
-      return v.value.map(x => fromValue(x, vm))
+      return v.value.map(fromValue)
    case 'dict':
-      return Object.fromEntries(v.value.entries().map(([k, v]) => [k, fromValue(v, vm)]))
+      return Object.fromEntries(v.value.entries().map(([k, v]) => [k, fromValue(v)]))
    case 'regex':
      return v.value
    case 'function':
      if (!vm || !(vm instanceof VM)) {
        const stack = new Error().stack || ''
        const stackLines = stack.split('\n')
          .slice(1)
          .filter(line => !line.includes('fromValue'))
          .map(line => '    ' + line.trim())
          .join('\n')
        throw new Error(
          `VM is required for function conversion\n` +
          `  Function params: [${v.params.join(', ')}]\n` +
          `  Function body at instruction: ${v.body}\n` +
          `  Called from:\n${stackLines}`
        )
      }
      return fnFromValue(v, vm)
    case 'native':
-      return getOriginalFunction(v.fn)
+      return '<function>'
  }
 }
 export function toNull(): Value {
  return toValue(null)
 }
 export function fnFromValue(fn: Value, vm: VM): Function {
  if (fn.type !== 'function')
    throw new Error('Value is not a function')
  const wrapper = async function (...args: any[]) {
    let positional: any[] = args
    let named: Record<string, any> = {}
    if (args.length > 0 && !Array.isArray(args[args.length - 1]) && args[args.length - 1].constructor === Object) {
      named = args[args.length - 1]
      positional = args.slice(0, -1)
    }
    const newVM = new VM({
      instructions: vm.instructions,
      constants: vm.constants,
      labels: vm.labels
    })
    newVM.scope = fn.parentScope
    newVM.stack.push(fn)
    newVM.stack.push(...positional.map(x => toValue(x, vm)))
    for (const [key, val] of Object.entries(named)) {
      newVM.stack.push(toValue(key))
      newVM.stack.push(toValue(val, vm))
    }
    newVM.stack.push(toValue(positional.length))
    newVM.stack.push(toValue(Object.keys(named).length))
    const targetDepth = newVM.callStack.length
    await newVM.execute({ op: OpCode.CALL })
    newVM.pc++
    while (newVM.callStack.length > targetDepth && newVM.pc < newVM.instructions.length) {
      await newVM.execute(newVM.instructions[newVM.pc]!)
      newVM.pc++
    }
    return fromValue(newVM.stack.pop() || toNull(), vm)
  }
    // support roundtrips, eg fromValue(toValue(fn))
    ; (wrapper as any)[REEF_FUNCTION] = fn
  return wrapper
 }
--- a/src/vm.ts
+++ b/src/vm.ts
@ -3,9 +3,8 @@ import type { ExceptionHandler } from "./exception"
 import { type Frame } from "./frame"
 import { OpCode } from "./opcode"
 import { Scope } from "./scope"
-import type { Value, NativeFunction, TypeScriptFunction } from "./value"
+import { type Value, type NativeFunction, toValue, toNumber, isTrue, isEqual, toString, fromValue } from "./value"
-import { toValue, toNumber, isTrue, isEqual, toString, fromValue, fnFromValue } from "./value"
+import { extractParamInfo, wrapNative, isWrapped, getOriginalFunction } from "./function"
 import { extractParamInfo, getOriginalFunction } from "./function"
 export class VM {
  pc = 0
@ -19,71 +18,26 @@ export class VM {
  labels: Map<number, string> = new Map()
  nativeFunctions: Map<string, NativeFunction> = new Map()
-  constructor(bytecode: Bytecode, globals?: Record<string, any>) {
+  constructor(bytecode: Bytecode, functions?: Record<string, Function>) {
    this.instructions = bytecode.instructions
    this.constants = bytecode.constants
    this.labels = bytecode.labels || new Map()
    this.scope = new Scope()
-    if (globals) {
+    if (functions)
-      for (const name of Object.keys(globals ?? {}))
+      for (const name of Object.keys(functions))
-        this.set(name, globals[name])
+        this.registerFunction(name, functions[name]!)
      this.scope = new Scope(this.scope)
    }
  }
-  async call(name: string, ...args: any) {
+  registerFunction(name: string, fn: Function) {
-    const value = this.scope.get(name)
+    const wrapped = isWrapped(fn) ? fn as NativeFunction : wrapNative(fn)
-
+    this.scope.set(name, { type: 'native', fn: wrapped, value: '<function>' })
    if (!value) throw new Error(`Can't find ${name}`)
    if (value.type !== 'function' && value.type !== 'native')
      throw new Error(`Can't call ${name}`)
    if (value.type === 'native') {
      return await this.callNative(value.fn, args)
    } else {
      const fn = fnFromValue(value, this)
      return await fn(...args)
    }
  }
-  has(name: string): boolean {
+  registerValueFunction(name: string, fn: NativeFunction) {
    return this.scope.has(name)
  }
  vars(): string[] {
    return this.scope.vars()
  }
  get(name: string) {
    return this.scope.get(name)
  }
  set(name: string, value: any) {
    this.scope.set(name, toValue(value, this))
  }
  setFunction(name: string, fn: TypeScriptFunction) {
    this.scope.set(name, toValue(fn, this))
  }
  setValueFunction(name: string, fn: NativeFunction) {
    this.scope.set(name, { type: 'native', fn, value: '<function>' })
  }
  pushScope(locals?: Record<string, any>) {
    this.scope = new Scope(this.scope)
    if (locals)
      for (const [name, value] of Object.entries(locals))
        this.set(name, value)
  }
  popScope() {
    this.scope = this.scope.parent!
  }
  async run(): Promise<Value> {
    this.pc = 0
    this.stopped = false
@ -97,57 +51,6 @@ export class VM {
    return this.stack[this.stack.length - 1] || toValue(null)
  }
  // Resume execution from current PC without resetting
  // Useful for REPL mode where you append bytecode incrementally
  async continue(): Promise<Value> {
    this.stopped = false
    while (!this.stopped && this.pc < this.instructions.length) {
      const instruction = this.instructions[this.pc]!
      await this.execute(instruction)
      this.pc++
    }
    return this.stack[this.stack.length - 1] || toValue(null)
  }
  // Helper for REPL mode: append new bytecode with proper constant index remapping
  appendBytecode(bytecode: Bytecode): void {
    const constantOffset = this.constants.length
    const instructionOffset = this.instructions.length
    // Remap function body addresses in constants before adding them
    for (const constant of bytecode.constants) {
      if (constant.type === 'function_def') {
        this.constants.push({ ...constant, body: constant.body + instructionOffset })
      } else {
        this.constants.push(constant)
      }
    }
    for (const instruction of bytecode.instructions) {
      if (instruction.operand !== undefined && typeof instruction.operand === 'number') {
        // Opcodes that reference constants need their operand adjusted
        if (instruction.op === OpCode.PUSH || instruction.op === OpCode.MAKE_FUNCTION) {
          this.instructions.push({
            op: instruction.op,
            operand: instruction.operand + constantOffset
          })
        } else {
          this.instructions.push(instruction)
        }
      } else {
        this.instructions.push(instruction)
      }
    }
    if (bytecode.labels) {
      for (const [addr, label] of bytecode.labels.entries()) {
        this.labels.set(addr + instructionOffset, label)
      }
    }
  }
  async execute(instruction: Instruction) /* throws */ {
    switch (instruction.op) {
      case OpCode.PUSH:
@ -168,32 +71,8 @@ export class VM {
        this.stack.push(this.stack[this.stack.length - 1]!)
        break
      case OpCode.SWAP:
        const first = this.stack.pop()!
        const second = this.stack.pop()!
        this.stack.push(first)
        this.stack.push(second)
        break
      case OpCode.ADD:
-        const b = this.stack.pop()!
+        this.binaryOp((a, b) => toNumber(a) + toNumber(b))
        const a = this.stack.pop()!
        if (a.type === 'string' || b.type === 'string') {
          this.stack.push(toValue(toString(a) + toString(b)))
        } else if (a.type === 'array' && b.type === 'array') {
          this.stack.push({ type: 'array', value: [...a.value, ...b.value] })
        } else if (a.type === 'dict' && b.type === 'dict') {
          const merged = new Map(a.value)
          for (const [key, value] of b.value) {
            merged.set(key, value)
          }
          this.stack.push({ type: 'dict', value: merged })
        } else if (a.type === 'number' && b.type === 'number') {
          this.stack.push(toValue(a.value + b.value))
        } else {
          throw new Error(`ADD: Cannot add ${a.type} and ${b.type}`)
        }
        break
      case OpCode.SUB:
@ -241,31 +120,6 @@ export class VM {
        this.stack.push({ type: 'boolean', value: !isTrue(val) })
        break
      // Bitwise operations
      case OpCode.BIT_AND:
        this.binaryOp((a, b) => (toNumber(a) | 0) & (toNumber(b) | 0))
        break
      case OpCode.BIT_OR:
        this.binaryOp((a, b) => (toNumber(a) | 0) | (toNumber(b) | 0))
        break
      case OpCode.BIT_XOR:
        this.binaryOp((a, b) => (toNumber(a) | 0) ^ (toNumber(b) | 0))
        break
      case OpCode.BIT_SHL:
        this.binaryOp((a, b) => (toNumber(a) | 0) << (toNumber(b) | 0))
        break
      case OpCode.BIT_SHR:
        this.binaryOp((a, b) => (toNumber(a) | 0) >> (toNumber(b) | 0))
        break
      case OpCode.BIT_USHR:
        this.binaryOp((a, b) => (toNumber(a) | 0) >>> (toNumber(b) | 0))
        break
      case OpCode.HALT:
        this.stopped = true
        break
@ -286,18 +140,13 @@ export class VM {
        const value = this.scope.get(varName)
        if (value === undefined)
-          this.stack.push(toValue(varName, this))
+          this.stack.push(toValue(varName))
        else
          this.stack.push(value)
        break
      }
      case OpCode.TYPE:
        const value = this.stack.pop()!
        this.stack.push(toValue(value.type))
        break
      case OpCode.STORE:
        const name = instruction.operand as string
        const toStore = this.stack.pop()!
@ -493,10 +342,10 @@ export class VM {
        const target = this.stack.pop()!
        if (target.type === 'array')
-          this.stack.push(toValue(target.value?.[Number(index.value)], this))
+          this.stack.push(toValue(target.value?.[Number(index.value)]))
        else if (target.type === 'dict')
-          this.stack.push(toValue(target.value?.get(String(index.value)), this))
+          this.stack.push(toValue(target.value?.get(String(index.value))))
        else
          throw new Error(`DOT_GET: ${target.type} not supported`)
@ -602,25 +451,16 @@ export class VM {
          let nativePositionalArgIndex = 0
          // Bind fixed parameters using priority: named arg > positional arg > default > null
          // Note: null values trigger defaults (null acts as "use default")
          for (let i = 0; i < nativeFixedParamCount; i++) {
            const paramName = paramInfo.params[i]!
            let paramValue: Value | undefined
            // Check if named argument was provided for this param
            if (namedArgs.has(paramName)) {
-              paramValue = namedArgs.get(paramName)!
+              nativeArgs.push(namedArgs.get(paramName)!)
              namedArgs.delete(paramName) // Remove from named args so it won't go to @named
            } else if (nativePositionalArgIndex < positionalArgs.length) {
-              paramValue = positionalArgs[nativePositionalArgIndex]!
+              nativeArgs.push(positionalArgs[nativePositionalArgIndex]!)
              nativePositionalArgIndex++
            }
            // If the parameter value is null and a default exists, use the default
            if (paramValue?.type === 'null' && paramInfo.defaults[paramName] !== undefined) {
              nativeArgs.push(paramInfo.defaults[paramName]!)
            } else if (paramValue) {
              nativeArgs.push(paramValue)
            } else if (paramInfo.defaults[paramName] !== undefined) {
              nativeArgs.push(paramInfo.defaults[paramName]!)
            } else {
@ -636,8 +476,8 @@ export class VM {
              namedDict.set(key, value)
            }
            // Convert dict to plain JavaScript object for the native function
-            const namedObj = fromValue({ type: 'dict', value: namedDict }, this)
+            const namedObj = fromValue({ type: 'dict', value: namedDict })
-            nativeArgs.push(toValue(namedObj, this))
+            nativeArgs.push(toValue(namedObj))
          }
          // Handle variadic parameter (TypeScript rest parameters)
@ -649,41 +489,13 @@ export class VM {
          }
          // Call the native function with bound args
-          try {
+          const result = await fn.fn(...nativeArgs)
            const result = await fn.fn.call(this, ...nativeArgs)
          this.stack.push(result)
          break
          } catch (error) {
            const errorMessage = error instanceof Error ? error.message : String(error)
            const errorValue = toValue(errorMessage)
            // no exception handlers, let it crash
            if (this.exceptionHandlers.length === 0) {
              throw new Error(errorMessage)
            }
            // use existing THROW logic
            const throwHandler = this.exceptionHandlers.pop()!
            while (this.callStack.length > throwHandler.callStackDepth)
              this.callStack.pop()
            this.scope = throwHandler.scope
            this.stack.push(errorValue)
            // Jump to `finally` if present, otherwise jump to `catch`
            const targetAddress = throwHandler.finallyAddress !== undefined
              ? throwHandler.finallyAddress
              : throwHandler.catchAddress
            // subtract 1 because pc will be incremented
            this.pc = targetAddress - 1
            break
          }
        }
        if (fn.type !== 'function')
-          throw new Error(`CALL: ${fn.value} is not a function`)
+          throw new Error('CALL: not a function')
        if (this.callStack.length > 0)
          this.callStack[this.callStack.length - 1]!.isBreakTarget = true
@ -705,29 +517,16 @@ export class VM {
        let positionalArgIndex = 0
        // Bind fixed parameters using priority: named arg > positional arg > default > null
        // Note: null values trigger defaults (null acts as "use default")
        for (let i = 0; i < fixedParamCount; i++) {
          const paramName = fn.params[i]!
          let paramValue: Value | undefined
          // Check if named argument was provided for this param
          if (namedArgs.has(paramName)) {
-            paramValue = namedArgs.get(paramName)!
+            this.scope.set(paramName, namedArgs.get(paramName)!)
            namedArgs.delete(paramName) // Remove from named args so it won't go to named
          } else if (positionalArgIndex < positionalArgs.length) {
-            paramValue = positionalArgs[positionalArgIndex]!
+            this.scope.set(paramName, positionalArgs[positionalArgIndex]!)
            positionalArgIndex++
          }
          // If the parameter value is null and a default exists, use the default
          if (paramValue && paramValue.type === 'null' && fn.defaults[paramName] !== undefined) {
            const defaultIdx = fn.defaults[paramName]!
            const defaultValue = this.constants[defaultIdx]!
            if (defaultValue.type === 'function_def')
              throw new Error('Default value cannot be a function definition')
            this.scope.set(paramName, defaultValue)
          } else if (paramValue) {
            this.scope.set(paramName, paramValue)
          } else if (fn.defaults[paramName] !== undefined) {
            const defaultIdx = fn.defaults[paramName]!
            const defaultValue = this.constants[defaultIdx]!
@ -788,7 +587,7 @@ export class VM {
        const tailFn = this.stack.pop()!
        if (tailFn.type !== 'function')
-          throw new Error(`TAIL_CALL: ${tailFn.value} is not a function`)
+          throw new Error('TAIL_CALL: not a function')
        this.scope = new Scope(tailFn.parentScope)
@ -857,7 +656,7 @@ export class VM {
        break
      default:
-        throw new Error(`Unknown op: ${instruction.op}`)
+        throw `Unknown op: ${instruction.op}`
    }
  }
@ -874,26 +673,4 @@ export class VM {
    const result = fn(a, b)
    this.stack.push({ type: 'boolean', value: result })
  }
  async callNative(nativeFn: NativeFunction, args: any[]): Promise<Value> {
    const originalFn = getOriginalFunction(nativeFn)
    const lastArg = args[args.length - 1]
    if (lastArg && !Array.isArray(lastArg) && typeof lastArg === 'object') {
      const paramInfo = extractParamInfo(originalFn)
      const positional = args.slice(0, -1)
      const named = lastArg
      args = [...positional]
      for (let i = positional.length; i < paramInfo.params.length; i++) {
        const paramName = paramInfo.params[i]!
        if (named[paramName] !== undefined) {
          args[i] = named[paramName]
        }
      }
    }
    const result = await originalFn.call(this, ...args)
    return toValue(result, this)
  }
 }
--- a/tests/bitwise.test.ts
+++ b/tests/bitwise.test.ts
@ -1,107 +0,0 @@
 import { expect, describe, test } from 'bun:test'
 import { toBytecode, run } from '#reef'
 describe('bitwise operations', () => {
  test('BIT_AND', async () => {
    const bytecode = toBytecode([
      ["PUSH", 5], ["PUSH", 3], ["BIT_AND"], ["HALT"]
    ])
    await expect(bytecode).toBeNumber(1)
  })
  test('BIT_AND with zero', async () => {
    const bytecode = toBytecode([
      ["PUSH", 5], ["PUSH", 0], ["BIT_AND"], ["HALT"]
    ])
    await expect(bytecode).toBeNumber(0)
  })
  test('BIT_OR', async () => {
    const bytecode = toBytecode([
      ["PUSH", 5], ["PUSH", 3], ["BIT_OR"], ["HALT"]
    ])
    await expect(bytecode).toBeNumber(7)
  })
  test('BIT_OR with zero', async () => {
    const bytecode = toBytecode([
      ["PUSH", 5], ["PUSH", 0], ["BIT_OR"], ["HALT"]
    ])
    await expect(bytecode).toBeNumber(5)
  })
  test('BIT_XOR', async () => {
    const bytecode = toBytecode([
      ["PUSH", 5], ["PUSH", 3], ["BIT_XOR"], ["HALT"]
    ])
    await expect(bytecode).toBeNumber(6)
  })
  test('BIT_XOR with itself returns zero', async () => {
    const bytecode = toBytecode([
      ["PUSH", 5], ["PUSH", 5], ["BIT_XOR"], ["HALT"]
    ])
    await expect(bytecode).toBeNumber(0)
  })
  test('BIT_SHL', async () => {
    const bytecode = toBytecode([
      ["PUSH", 5], ["PUSH", 2], ["BIT_SHL"], ["HALT"]
    ])
    await expect(bytecode).toBeNumber(20)
  })
  test('BIT_SHL by zero', async () => {
    const bytecode = toBytecode([
      ["PUSH", 5], ["PUSH", 0], ["BIT_SHL"], ["HALT"]
    ])
    await expect(bytecode).toBeNumber(5)
  })
  test('BIT_SHR', async () => {
    const bytecode = toBytecode([
      ["PUSH", 20], ["PUSH", 2], ["BIT_SHR"], ["HALT"]
    ])
    await expect(bytecode).toBeNumber(5)
  })
  test('BIT_SHR preserves sign for negative numbers', async () => {
    const bytecode = toBytecode([
      ["PUSH", -20], ["PUSH", 2], ["BIT_SHR"], ["HALT"]
    ])
    await expect(bytecode).toBeNumber(-5)
  })
  test('BIT_USHR', async () => {
    const bytecode = toBytecode([
      ["PUSH", -1], ["PUSH", 1], ["BIT_USHR"], ["HALT"]
    ])
    await expect(bytecode).toBeNumber(2147483647)
  })
  test('BIT_USHR does not preserve sign', async () => {
    const bytecode = toBytecode([
      ["PUSH", -8], ["PUSH", 1], ["BIT_USHR"], ["HALT"]
    ])
    await expect(bytecode).toBeNumber(2147483644)
  })
  test('compound bitwise operations', async () => {
    const bytecode = toBytecode([
      // (5 & 3) | (8 ^ 12)
      ["PUSH", 5], ["PUSH", 3], ["BIT_AND"],    // stack: [1]
      ["PUSH", 8], ["PUSH", 12], ["BIT_XOR"],   // stack: [1, 4]
      ["BIT_OR"],                                // stack: [5]
      ["HALT"]
    ])
    await expect(bytecode).toBeNumber(5)
  })
  test('shift with large shift amounts', async () => {
    const bytecode = toBytecode([
      ["PUSH", 1], ["PUSH", 31], ["BIT_SHL"], ["HALT"]
    ])
    // 1 << 31 = -2147483648 (most significant bit set)
    await expect(bytecode).toBeNumber(-2147483648)
  })
 })
--- a/tests/exceptions.test.ts
+++ b/tests/exceptions.test.ts
@ -15,7 +15,7 @@ test("PUSH_TRY and POP_TRY - no exception thrown", async () => {
    PUSH 999
    HALT
  `
-  await expect(str).toBeNumber(52)
+  expect(await run(toBytecode(str))).toEqual({ type: 'number', value: 52 })
 })
 test("THROW - catch exception with error value", async () => {
@ -29,7 +29,7 @@ test("THROW - catch exception with error value", async () => {
    .catch:
    HALT
  `
-  await expect(str).toBeString('error occurred')
+  expect(await run(toBytecode(str))).toEqual({ type: 'string', value: 'error occurred' })
 })
 test("THROW - uncaught exception throws JS error", async () => {
@ -58,7 +58,7 @@ test("THROW - exception with nested try blocks", async () => {
    PUSH "outer error"
    HALT
  `
-  await expect(str).toBeString('inner error')
+  expect(await run(toBytecode(str))).toEqual({ type: 'string', value: 'inner error' })
 })
 test("THROW - exception skips outer handler", async () => {
@ -75,7 +75,7 @@ test("THROW - exception skips outer handler", async () => {
    .outer_catch:
    HALT
  `
-  await expect(str).toBeString('error message')
+  expect(await run(toBytecode(str))).toEqual({ type: 'string', value: 'error message' })
 })
 test("THROW - exception unwinds call stack", async () => {
@ -150,7 +150,7 @@ test("PUSH_FINALLY - finally executes after successful try", async () => {
    ADD
    HALT
  `
-  await expect(str).toBeNumber(110)
+  expect(await run(toBytecode(str))).toEqual({ type: 'number', value: 110 })
 })
 test("PUSH_FINALLY - finally executes after exception", async () => {
@ -169,7 +169,7 @@ test("PUSH_FINALLY - finally executes after exception", async () => {
    PUSH "finally ran"
    HALT
  `
-  await expect(str).toBeString('finally ran')
+  expect(await run(toBytecode(str))).toEqual({ type: 'string', value: 'finally ran' })
 })
 test("PUSH_FINALLY - finally without catch", async () => {
@ -189,7 +189,7 @@ test("PUSH_FINALLY - finally without catch", async () => {
    ADD
    HALT
  `
-  await expect(str).toBeNumber(52)
+  expect(await run(toBytecode(str))).toEqual({ type: 'number', value: 52 })
 })
 test("PUSH_FINALLY - nested try-finally blocks", async () => {
@ -214,7 +214,7 @@ test("PUSH_FINALLY - nested try-finally blocks", async () => {
    ADD
    HALT
  `
-  await expect(str).toBeNumber(11)
+  expect(await run(toBytecode(str))).toEqual({ type: 'number', value: 11 })
 })
 test("PUSH_FINALLY - error when no handler", async () => {
--- a/tests/functions-parameter.test.ts
+++ b/tests/functions-parameter.test.ts
@ -104,7 +104,7 @@ describe("functions parameter", () => {
    expect(result).toEqual({ type: 'number', value: 200 })
  })
-  test("can combine with manual vm.set", async () => {
+  test("can combine with manual registerFunction", async () => {
    const bytecode = toBytecode(`
      LOAD add
      PUSH 5
@ -127,7 +127,7 @@ describe("functions parameter", () => {
    })
    // Register another function manually
-    vm.set('subtract', (a: number, b: number) => a - b)
+    vm.registerFunction('subtract', (a: number, b: number) => a - b)
    const result = await vm.run()
    expect(result).toEqual({ type: 'number', value: 6 })
@ -224,7 +224,7 @@ describe("functions parameter", () => {
    })
    // Override with manual registration
-    vm.set('getValue', () => 200)
+    vm.registerFunction('getValue', () => 200)
    const result = await vm.run()
    expect(result).toEqual({ type: 'number', value: 200 })
--- a/tests/functions.test.ts
+++ b/tests/functions.test.ts
@ -487,7 +487,7 @@ test("TRY_CALL - handles null values", async () => {
 test("TRY_CALL - function can access its parameters", async () => {
  const bytecode = toBytecode([
-    ["MAKE_FUNCTION", ["x=0"], ".body"],
+    ["MAKE_FUNCTION", ["x"], ".body"],
    ["STORE", "addFive"],
    ["PUSH", 10],
    ["STORE", "x"],
@ -501,8 +501,8 @@ test("TRY_CALL - function can access its parameters", async () => {
  ])
  const result = await run(bytecode)
-  // Function is called with 0 args, so x defaults to 0
+  // Function is called with 0 args, so x inside function should be null
-  // Then we add 5 to 0
+  // Then we add 5 to null (which coerces to 0)
  expect(result).toEqual({ type: 'number', value: 5 })
 })
@ -519,206 +519,3 @@ test("TRY_CALL - with string format", async () => {
  const result = await run(bytecode)
  expect(result).toEqual({ type: 'number', value: 100 })
 })
 test("CALL - passing null triggers default value for single parameter", async () => {
  const bytecode = toBytecode([
    ["MAKE_FUNCTION", ["x=42"], ".body"],
    ["STORE", "func"],
    ["JUMP", ".end"],
    [".body:"],
    ["LOAD", "x"],
    ["RETURN"],
    [".end:"],
    ["LOAD", "func"],
    ["PUSH", null],
    ["PUSH", 1],
    ["PUSH", 0],
    ["CALL"],
    ["HALT"]
  ])
  const result = await run(bytecode)
  // Passing null should trigger the default value of 42
  expect(result).toEqual({ type: 'number', value: 42 })
 })
 test("CALL - passing null triggers default value for multiple parameters", async () => {
  const bytecode = toBytecode([
    ["MAKE_FUNCTION", ["a=10", "b=20", "c=30"], ".body"],
    ["STORE", "func"],
    ["JUMP", ".end"],
    [".body:"],
    ["LOAD", "a"],
    ["LOAD", "b"],
    ["ADD"],
    ["LOAD", "c"],
    ["ADD"],
    ["RETURN"],
    [".end:"],
    ["LOAD", "func"],
    ["PUSH", 5],
    ["PUSH", null],
    ["PUSH", null],
    ["PUSH", 3],
    ["PUSH", 0],
    ["CALL"],
    ["HALT"]
  ])
  const result = await run(bytecode)
  // a=5 (provided), b=20 (null triggers default), c=30 (null triggers default)
  // Result: 5 + 20 + 30 = 55
  expect(result).toEqual({ type: 'number', value: 55 })
 })
 test("CALL - null in middle parameter triggers default", async () => {
  const bytecode = toBytecode([
    ["MAKE_FUNCTION", ["x=100", "y=200", "z=300"], ".body"],
    ["STORE", "func"],
    ["JUMP", ".end"],
    [".body:"],
    ["LOAD", "x"],
    ["LOAD", "y"],
    ["ADD"],
    ["LOAD", "z"],
    ["ADD"],
    ["RETURN"],
    [".end:"],
    ["LOAD", "func"],
    ["PUSH", 1],
    ["PUSH", null],
    ["PUSH", 3],
    ["PUSH", 3],
    ["PUSH", 0],
    ["CALL"],
    ["HALT"]
  ])
  const result = await run(bytecode)
  // x=1, y=200 (null triggers default), z=3
  // Result: 1 + 200 + 3 = 204
  expect(result).toEqual({ type: 'number', value: 204 })
 })
 test("CALL - null with named arguments triggers default", async () => {
  const bytecode = toBytecode([
    ["MAKE_FUNCTION", ["x=50", "y=75"], ".body"],
    ["STORE", "func"],
    ["JUMP", ".end"],
    [".body:"],
    ["LOAD", "x"],
    ["LOAD", "y"],
    ["ADD"],
    ["RETURN"],
    [".end:"],
    ["LOAD", "func"],
    ["PUSH", "x"],
    ["PUSH", null],
    ["PUSH", "y"],
    ["PUSH", 25],
    ["PUSH", 0],
    ["PUSH", 2],
    ["CALL"],
    ["HALT"]
  ])
  const result = await run(bytecode)
  // x=50 (null triggers default), y=25 (provided via named arg)
  // Result: 50 + 25 = 75
  expect(result).toEqual({ type: 'number', value: 75 })
 })
 test("CALL - null with string default value", async () => {
  const bytecode = toBytecode([
    ["MAKE_FUNCTION", ["name='Guest'"], ".body"],
    ["STORE", "greet"],
    ["JUMP", ".end"],
    [".body:"],
    ["PUSH", "Hello, "],
    ["LOAD", "name"],
    ["ADD"],
    ["RETURN"],
    [".end:"],
    ["LOAD", "greet"],
    ["PUSH", null],
    ["PUSH", 1],
    ["PUSH", 0],
    ["CALL"],
    ["HALT"]
  ])
  const result = await run(bytecode)
  // Passing null should trigger the default value 'Guest'
  expect(result).toEqual({ type: 'string', value: 'Hello, Guest' })
 })
 test("CALL - null with no default still results in null", async () => {
  const bytecode = toBytecode([
    ["MAKE_FUNCTION", ["x"], ".body"],
    ["STORE", "func"],
    ["JUMP", ".end"],
    [".body:"],
    ["LOAD", "x"],
    ["RETURN"],
    [".end:"],
    ["LOAD", "func"],
    ["PUSH", null],
    ["PUSH", 1],
    ["PUSH", 0],
    ["CALL"],
    ["HALT"]
  ])
  const result = await run(bytecode)
  // No default value, so null should be returned
  expect(result).toEqual({ type: 'null', value: null })
 })
 test("CALL - null triggers default with variadic parameters", async () => {
  const bytecode = toBytecode([
    ["MAKE_FUNCTION", ["x=99", "...rest"], ".body"],
    ["STORE", "func"],
    ["JUMP", ".end"],
    [".body:"],
    ["LOAD", "x"],
    ["RETURN"],
    [".end:"],
    ["LOAD", "func"],
    ["PUSH", null],
    ["PUSH", 1],
    ["PUSH", 2],
    ["PUSH", 3],
    ["PUSH", 4],
    ["PUSH", 0],
    ["CALL"],
    ["HALT"]
  ])
  const result = await run(bytecode)
  // x should be 99 (null triggers default), rest gets [1, 2, 3]
  expect(result).toEqual({ type: 'number', value: 99 })
 })
 test("CALL - null triggers default with @named parameter", async () => {
  const bytecode = toBytecode([
    ["MAKE_FUNCTION", ["x=777", "@named"], ".body"],
    ["STORE", "func"],
    ["JUMP", ".end"],
    [".body:"],
    ["LOAD", "x"],
    ["RETURN"],
    [".end:"],
    ["LOAD", "func"],
    ["PUSH", null],
    ["PUSH", "foo"],
    ["PUSH", "bar"],
    ["PUSH", 1],
    ["PUSH", 1],
    ["CALL"],
    ["HALT"]
  ])
  const result = await run(bytecode)
  // x should be 777 (null triggers default)
  expect(result).toEqual({ type: 'number', value: 777 })
 })
--- a/tests/native.test.ts
+++ b/tests/native.test.ts
--- a/tests/opcodes.test.ts
+++ b/tests/opcodes.test.ts
--- a/tests/regex.test.ts
+++ b/tests/regex.test.ts
@ -159,14 +159,14 @@ describe("RegExp", () => {
    PUSH /bar/
    NEQ
    `
-    await expect(str).toBeBoolean(true)
+    expect(await run(toBytecode(str))).toEqual({ type: 'boolean', value: true })
    const str2 = `
    PUSH /test/i
    PUSH /test/i
    NEQ
    `
-    await expect(str2).toBeBoolean(false)
+    expect(await run(toBytecode(str2))).toEqual({ type: 'boolean', value: false })
  })
  test("is truthy", async () => {
@ -177,7 +177,7 @@ describe("RegExp", () => {
    PUSH 42
    .end:
    `
-    await expect(str).toBeNumber(42)
+    expect(await run(toBytecode(str))).toEqual({ type: 'number', value: 42 })
  })
  test("NOT returns false (regex is truthy)", async () => {
@ -185,7 +185,7 @@ describe("RegExp", () => {
    PUSH /pattern/
    NOT
    `
-    await expect(str).toBeBoolean(false)
+    expect(await run(toBytecode(str))).toEqual({ type: 'boolean', value: false })
  })
  test("in arrays", async () => {
@ -301,7 +301,7 @@ describe("RegExp", () => {
    PUSH /bar/i
    STR_CONCAT #3
    `
-    await expect(str).toBeString('/foo/ and /bar/i')
+    expect(await run(toBytecode(str))).toEqual({ type: 'string', value: '/foo/ and /bar/i' })
  })
  test("DUP with regex", async () => {
@ -311,7 +311,7 @@ describe("RegExp", () => {
    EQ
    `
    // Same regex duplicated should be equal
-    await expect(str).toBeBoolean(true)
+    expect(await run(toBytecode(str))).toEqual({ type: 'boolean', value: true })
  })
  test("empty pattern", async () => {
@ -365,7 +365,7 @@ describe("RegExp", () => {
    PUSH /xyz/
    EQ
    `
-    await expect(str1).toBeBoolean(false)
+    expect(await run(toBytecode(str1))).toEqual({ type: 'boolean', value: false })
    // Same pattern, different flags
    const str2 = `
@ -373,7 +373,7 @@ describe("RegExp", () => {
    PUSH /test/i
    EQ
    `
-    await expect(str2).toBeBoolean(false)
+    expect(await run(toBytecode(str2))).toEqual({ type: 'boolean', value: false })
    // Different order of flags (should be equal)
    const str3 = `
@ -381,7 +381,7 @@ describe("RegExp", () => {
    PUSH /test/gi
    EQ
    `
-    await expect(str3).toBeBoolean(true)
+    expect(await run(toBytecode(str3))).toEqual({ type: 'boolean', value: true })
  })
  test("with native functions", async () => {
@ -399,7 +399,7 @@ describe("RegExp", () => {
    const vm = new VM(bytecode)
    // Register a native function that takes a string and regex
-    vm.set('match', (str: string, pattern: RegExp) => {
+    vm.registerFunction('match', (str: string, pattern: RegExp) => {
      return pattern.test(str)
    })
@ -422,7 +422,7 @@ describe("RegExp", () => {
    const vm = new VM(bytecode)
-    vm.set('replace', (str: string, pattern: RegExp, replacement: string) => {
+    vm.registerFunction('replace', (str: string, pattern: RegExp, replacement: string) => {
      return str.replace(pattern, replacement)
    })
@ -444,7 +444,7 @@ describe("RegExp", () => {
    const vm = new VM(bytecode)
-    vm.set('extractNumbers', (str: string, pattern: RegExp) => {
+    vm.registerFunction('extractNumbers', (str: string, pattern: RegExp) => {
      return str.match(pattern) || []
    })
--- a/tests/repl.test.ts
+++ b/tests/repl.test.ts
@ -1,149 +0,0 @@
 import { test, expect } from "bun:test"
 import { VM, toBytecode } from "#reef"
 test("REPL mode - demonstrates PC reset problem", async () => {
  // Track how many times each line executes
  let line1Count = 0
  let line2Count = 0
  // Line 1: Set x = 5, track execution
  const line1 = toBytecode([
    ["LOAD", "trackLine1"],
    ["PUSH", 0],
    ["PUSH", 0],
    ["CALL"],
    ["POP"],
    ["PUSH", 5],
    ["STORE", "x"]
  ])
  const vm = new VM(line1, {
    trackLine1: () => { line1Count++; return null },
    trackLine2: () => { line2Count++; return null }
  })
  await vm.run()
  expect(vm.scope.get("x")).toEqual({ type: "number", value: 5 })
  expect(line1Count).toBe(1)
  expect(line2Count).toBe(0)
  // Line 2: Track execution, load x
  const line2 = toBytecode([
    ["LOAD", "trackLine2"],
    ["PUSH", 0],
    ["PUSH", 0],
    ["CALL"],
    ["POP"],
    ["LOAD", "x"]
  ])
  // Append line2 bytecode to VM (what a REPL would do)
  vm.instructions.push(...line2.instructions)
  for (const constant of line2.constants) {
    if (!vm.constants.includes(constant)) {
      vm.constants.push(constant)
    }
  }
  // Current behavior: run() resets PC to 0, re-executing everything
  await vm.run()
  // PROBLEM: Line 1 ran AGAIN (count is now 2, not 1)
  // This is the issue for REPL - side effects run multiple times
  expect(line1Count).toBe(2) // Ran twice! Should still be 1
  expect(line2Count).toBe(1) // This is correct
  // What we WANT for REPL:
  // - Only execute the NEW bytecode (line 2)
  // - line1Count should stay at 1
  // - line2Count should be 1
 })
 test("REPL mode - continue() executes only new bytecode", async () => {
  // Track how many times each line executes
  let line1Count = 0
  let line2Count = 0
  // Line 1: Set x = 5, track execution
  const line1 = toBytecode([
    ["LOAD", "trackLine1"],
    ["PUSH", 0],
    ["PUSH", 0],
    ["CALL"],
    ["POP"],
    ["PUSH", 5],
    ["STORE", "x"]
  ])
  const vm = new VM(line1, {
    trackLine1: () => { line1Count++; return null },
    trackLine2: () => { line2Count++; return null }
  })
  await vm.run()
  expect(vm.scope.get("x")).toEqual({ type: "number", value: 5 })
  expect(line1Count).toBe(1)
  expect(line2Count).toBe(0)
  // Line 2: Track execution, load x and add 10
  const line2 = toBytecode([
    ["LOAD", "trackLine2"],
    ["PUSH", 0],
    ["PUSH", 0],
    ["CALL"],
    ["POP"],
    ["LOAD", "x"],
    ["PUSH", 10],
    ["ADD"]
  ])
  // Append line2 bytecode to VM using the helper method
  vm.appendBytecode(line2)
  // SOLUTION: Use continue() instead of run() to resume from current PC
  await vm.continue()
  const result = vm.stack[vm.stack.length - 1]
  // SUCCESS: Line 1 only ran once, line 2 ran once
  expect(line1Count).toBe(1) // Still 1! Side effect didn't re-run
  expect(line2Count).toBe(1) // Ran once as expected
  expect(result).toEqual({ type: "number", value: 15 }) // 5 + 10
 })
 test("REPL mode - function calls work across chunks", async () => {
  const vm = new VM(toBytecode([]))
  await vm.run()
  // Line 1: Define a function
  const line1 = toBytecode([
    ["MAKE_FUNCTION", ["x"], ".body"],
    ["STORE", "add1"],
    ["JUMP", ".end"],
    [".body:"],
    ["LOAD", "x"],
    ["PUSH", 1],
    ["ADD"],
    ["RETURN"],
    [".end:"]
  ])
  vm.appendBytecode(line1)
  await vm.continue()
  expect(vm.scope.get("add1")?.type).toBe("function")
  // Line 2: Call the function
  const line2 = toBytecode([
    ["LOAD", "add1"],
    ["PUSH", 10],
    ["PUSH", 1],
    ["PUSH", 0],
    ["CALL"]
  ])
  vm.appendBytecode(line2)
  const result = await vm.continue()
  expect(result).toEqual({ type: "number", value: 11 })
 })
--- a/tests/scope.test.ts
+++ b/tests/scope.test.ts
@ -1,243 +0,0 @@
 import { test, expect } from "bun:test"
 import { Scope, toValue } from "#reef"
 test("Scope - create empty scope", () => {
  const scope = new Scope()
  expect(scope.parent).toBeUndefined()
  expect(scope.locals.size).toBe(0)
 })
 test("Scope - create child scope with parent", () => {
  const parent = new Scope()
  const child = new Scope(parent)
  expect(child.parent).toBe(parent)
  expect(child.locals.size).toBe(0)
 })
 test("Scope - set and get variable in same scope", () => {
  const scope = new Scope()
  const value = toValue(42)
  scope.set("x", value)
  expect(scope.get("x")).toBe(value)
 })
 test("Scope - get returns undefined for non-existent variable", () => {
  const scope = new Scope()
  expect(scope.get("x")).toBeUndefined()
 })
 test("Scope - set updates existing variable in same scope", () => {
  const scope = new Scope()
  scope.set("x", toValue(10))
  expect(scope.get("x")).toEqual({ type: "number", value: 10 })
  scope.set("x", toValue(20))
  expect(scope.get("x")).toEqual({ type: "number", value: 20 })
 })
 test("Scope - get searches parent scope", () => {
  const parent = new Scope()
  const child = new Scope(parent)
  parent.set("x", toValue(42))
  expect(child.get("x")).toEqual({ type: "number", value: 42 })
 })
 test("Scope - get searches multiple levels up", () => {
  const grandparent = new Scope()
  const parent = new Scope(grandparent)
  const child = new Scope(parent)
  grandparent.set("x", toValue(100))
  expect(child.get("x")).toEqual({ type: "number", value: 100 })
 })
 test("Scope - child updates parent variable when it exists (no shadowing)", () => {
  const parent = new Scope()
  const child = new Scope(parent)
  parent.set("x", toValue(10))
  child.set("x", toValue(20))
  // set() updates parent's variable, not shadow it
  expect(parent.get("x")).toEqual({ type: "number", value: 20 })
  expect(child.get("x")).toEqual({ type: "number", value: 20 })
  expect(child.locals.has("x")).toBe(false)
 })
 test("Scope - set updates parent scope variable when it exists", () => {
  const parent = new Scope()
  const child = new Scope(parent)
  parent.set("x", toValue(10))
  child.set("x", toValue(20))
  // Should update parent's variable, not create new local one
  expect(parent.get("x")).toEqual({ type: "number", value: 20 })
  expect(child.get("x")).toEqual({ type: "number", value: 20 })
  expect(child.locals.has("x")).toBe(false)
 })
 test("Scope - set creates new local variable when not found in parent", () => {
  const parent = new Scope()
  const child = new Scope(parent)
  parent.set("x", toValue(10))
  child.set("y", toValue(20))
  expect(parent.get("x")).toEqual({ type: "number", value: 10 })
  expect(parent.get("y")).toBeUndefined()
  expect(child.get("x")).toEqual({ type: "number", value: 10 })
  expect(child.get("y")).toEqual({ type: "number", value: 20 })
  expect(child.locals.has("y")).toBe(true)
 })
 test("Scope - has returns true for variable in current scope", () => {
  const scope = new Scope()
  scope.set("x", toValue(42))
  expect(scope.has("x")).toBe(true)
  expect(scope.has("y")).toBe(false)
 })
 test("Scope - has returns true for variable in parent scope", () => {
  const parent = new Scope()
  const child = new Scope(parent)
  parent.set("x", toValue(42))
  expect(child.has("x")).toBe(true)
  expect(child.has("y")).toBe(false)
 })
 test("Scope - has searches multiple levels up", () => {
  const grandparent = new Scope()
  const parent = new Scope(grandparent)
  const child = new Scope(parent)
  grandparent.set("x", toValue(100))
  expect(child.has("x")).toBe(true)
  expect(parent.has("x")).toBe(true)
  expect(grandparent.has("x")).toBe(true)
 })
 test("Scope.vars() - returns empty array for empty scope", () => {
  const scope = new Scope()
  expect(scope.vars()).toEqual([])
 })
 test("Scope.vars() - returns single variable from current scope", () => {
  const scope = new Scope()
  scope.set("x", toValue(42))
  expect(scope.vars()).toEqual(["x"])
 })
 test("Scope.vars() - returns multiple variables from current scope", () => {
  const scope = new Scope()
  scope.set("x", toValue(1))
  scope.set("y", toValue(2))
  scope.set("z", toValue(3))
  const vars = scope.vars()
  expect(vars.length).toBe(3)
  expect(vars).toContain("x")
  expect(vars).toContain("y")
  expect(vars).toContain("z")
 })
 test("Scope.vars() - includes variables from parent scope", () => {
  const parent = new Scope()
  const child = new Scope(parent)
  parent.set("x", toValue(1))
  child.set("y", toValue(2))
  const vars = child.vars()
  expect(vars.length).toBe(2)
  expect(vars).toContain("x")
  expect(vars).toContain("y")
 })
 test("Scope.vars() - includes variables from multiple parent scopes", () => {
  const grandparent = new Scope()
  const parent = new Scope(grandparent)
  const child = new Scope(parent)
  grandparent.set("x", toValue(1))
  parent.set("y", toValue(2))
  child.set("z", toValue(3))
  const vars = child.vars()
  expect(vars.length).toBe(3)
  expect(vars).toContain("x")
  expect(vars).toContain("y")
  expect(vars).toContain("z")
 })
 test("Scope.vars() - no duplicates when child updates parent variable", () => {
  const parent = new Scope()
  const child = new Scope(parent)
  parent.set("x", toValue(10))
  child.set("x", toValue(20))  // Updates parent, doesn't create local
  // Only one "x" since child doesn't have its own local x
  const vars = child.vars()
  expect(vars).toEqual(["x"])
 })
 test("Scope.vars() - can't have duplicates if manually set in locals", () => {
  const parent = new Scope()
  const child = new Scope(parent)
  parent.set("x", toValue(10))
  child.locals.set("x", toValue(20))
  const vars = child.vars()
  expect(vars).toEqual(["x"])
  expect(child.get("x")).toEqual({ type: "number", value: 20 })
  expect(parent.get("x")).toEqual({ type: "number", value: 10 })
 })
 test("Scope.vars() - handles deep scope chains", () => {
  let scope = new Scope()
  // Create a deep chain: level0 -> level1 -> ... -> level5
  for (let i = 0; i < 5; i++) {
    scope.set(`var${i}`, toValue(i))
    scope = new Scope(scope)
  }
  // Final scope should have all variables from the chain
  const vars = scope.vars()
  expect(vars.length).toBe(5)
  expect(vars).toContain("var0")
  expect(vars).toContain("var1")
  expect(vars).toContain("var2")
  expect(vars).toContain("var3")
  expect(vars).toContain("var4")
 })
 test("Scope - can store and retrieve functions", () => {
  const scope = new Scope()
  const fnValue = {
    type: 'function' as const,
    value: '<function>' as const,
    params: ['x'],
    defaults: {},
    body: 0,
    variadic: false,
    named: false,
    parentScope: scope
  }
  scope.set("myFunc", fnValue)
  expect(scope.get("myFunc")).toBe(fnValue)
  expect(scope.get("myFunc")?.type).toBe("function")
 })
--- a/tests/setup.ts
+++ b/tests/setup.ts
@ -1,249 +0,0 @@
 import { expect } from "bun:test"
 import { toValue, fromValue, type Value, toBytecode, run, type Bytecode } from "#reef"
 import { isEqual } from "../src/value"
 declare module "bun:test" {
  interface Matchers<T> {
    /**
     * Run bytecode and assert that the result equals a JavaScript value after conversion via toValue()
     * @example expect(bytecode).toEqualValue(42)
     * @example expect("PUSH 5\nPUSH 3\nADD").toEqualValue(8)
     * @example expect([["PUSH", 42]]).toEqualValue(42)
     */
    toEqualValue(expected: any): Promise<void>
    /**
     * Run bytecode and assert that the result is null
     * @example expect(bytecode).toBeNull()
     * @example expect("PUSH null").toBeNull()
     */
    toBeNull(): Promise<void>
    /**
     * Run bytecode and assert that the result is a boolean with the expected value
     * @example expect(bytecode).toBeBoolean(true)
     * @example expect("PUSH true").toBeBoolean(true)
     */
    toBeBoolean(expected: boolean): Promise<void>
    /**
     * Run bytecode and assert that the result is a number with the expected value
     * @example expect(bytecode).toBeNumber(42)
     * @example expect("PUSH 42").toBeNumber(42)
     */
    toBeNumber(expected: number): Promise<void>
    /**
     * Run bytecode and assert that the result is a string with the expected value
     * @example expect(bytecode).toBeString("hello")
     * @example expect("PUSH \"hello\"").toBeString("hello")
     */
    toBeString(expected: string): Promise<void>
    /**
     * Run bytecode and assert that the result is an array with the expected values
     * @example expect(bytecode).toBeArray([1, 2, 3])
     */
    toBeArray(expected: any[]): Promise<void>
    /**
     * Run bytecode and assert that the result is a dict with the expected key-value pairs
     * @example expect(bytecode).toBeDict({ x: 10, y: 20 })
     */
    toBeDict(expected: Record<string, any>): Promise<void>
    /**
     * Run bytecode and assert that the result is a function (Reef or native)
     * @example expect(bytecode).toBeFunction()
     */
    toBeFunction(): Promise<void>
    /**
     * Run bytecode and assert that the result is truthy according to ReefVM semantics
     * (only null and false are falsy)
     * @example expect(bytecode).toBeTruthy()
     */
    toBeTruthy(): Promise<void>
    /**
     * Run bytecode and assert that the result is falsy according to ReefVM semantics
     * (only null and false are falsy)
     * @example expect(bytecode).toBeFalsy()
     */
    toBeFalsy(): Promise<void>
  }
 }
 expect.extend({
  async toEqualValue(this: void, received: unknown, expected: any) {
    const bytecode = typeof received === "string" || Array.isArray(received) ? toBytecode(received as string | any[]) : received as Bytecode
    const result = await run(bytecode)
    const expectedValue = toValue(expected)
    const pass = isEqual(result, expectedValue)
    return {
      pass,
      message: () =>
        pass
          ? `Expected value NOT to equal ${formatValue(expectedValue)}, but it did`
          : `Expected value to equal ${formatValue(expectedValue)}, but received ${formatValue(result)}`,
    }
  },
  async toBeNull(this: void, received: unknown) {
    const bytecode = typeof received === "string" || Array.isArray(received) ? toBytecode(received as string | any[]) : received as Bytecode
    const result = await run(bytecode)
    const pass = result.type === "null"
    return {
      pass,
      message: () =>
        pass
          ? `Expected value NOT to be null, but it was`
          : `Expected value to be null, but received ${formatValue(result)}`,
    }
  },
  async toBeBoolean(this: void, received: unknown, expected: boolean) {
    const bytecode = typeof received === "string" || Array.isArray(received) ? toBytecode(received as string | any[]) : received as Bytecode
    const result = await run(bytecode)
    const pass = result.type === "boolean" && result.value === expected
    return {
      pass,
      message: () =>
        pass
          ? `Expected value NOT to be boolean ${expected}, but it was`
          : `Expected value to be boolean ${expected}, but received ${formatValue(result)}`,
    }
  },
  async toBeNumber(this: void, received: unknown, expected: number) {
    const bytecode = typeof received === "string" || Array.isArray(received) ? toBytecode(received as string | any[]) : received as Bytecode
    const result = await run(bytecode)
    const pass = result.type === "number" && result.value === expected
    return {
      pass,
      message: () =>
        pass
          ? `Expected value NOT to be number ${expected}, but it was`
          : `Expected value to be number ${expected}, but received ${formatValue(result)}`,
    }
  },
  async toBeString(this: void, received: unknown, expected: string) {
    const bytecode = typeof received === "string" || Array.isArray(received) ? toBytecode(received as string | any[]) : received as Bytecode
    const result = await run(bytecode)
    const pass = result.type === "string" && result.value === expected
    return {
      pass,
      message: () =>
        pass
          ? `Expected value NOT to be string "${expected}", but it was`
          : `Expected value to be string "${expected}", but received ${formatValue(result)}`,
    }
  },
  async toBeArray(this: void, received: unknown, expected: any[]) {
    const bytecode = typeof received === "string" || Array.isArray(received) ? toBytecode(received as string | any[]) : received as Bytecode
    const result = await run(bytecode)
    const expectedValue = toValue(expected)
    const pass = result.type === "array" && isEqual(result, expectedValue)
    return {
      pass,
      message: () =>
        pass
          ? `Expected value NOT to be array ${formatValue(expectedValue)}, but it was`
          : `Expected value to be array ${formatValue(expectedValue)}, but received ${formatValue(result)}`,
    }
  },
  async toBeDict(this: void, received: unknown, expected: Record<string, any>) {
    const bytecode = typeof received === "string" || Array.isArray(received) ? toBytecode(received as string | any[]) : received as Bytecode
    const result = await run(bytecode)
    const expectedValue = toValue(expected)
    const pass = result.type === "dict" && isEqual(result, expectedValue)
    return {
      pass,
      message: () =>
        pass
          ? `Expected value NOT to be dict ${formatValue(expectedValue)}, but it was`
          : `Expected value to be dict ${formatValue(expectedValue)}, but received ${formatValue(result)}`,
    }
  },
  async toBeFunction(this: void, received: unknown) {
    const bytecode = typeof received === "string" || Array.isArray(received) ? toBytecode(received as string | any[]) : received as Bytecode
    const result = await run(bytecode)
    const pass = result.type === "function" || result.type === "native"
    return {
      pass,
      message: () =>
        pass
          ? `Expected value NOT to be a function, but it was`
          : `Expected value to be a function, but received ${formatValue(result)}`,
    }
  },
  async toBeTruthy(this: void, received: unknown) {
    const bytecode = typeof received === "string" || Array.isArray(received) ? toBytecode(received as string | any[]) : received as Bytecode
    const result = await run(bytecode)
    // ReefVM semantics: only null and false are falsy
    const pass = !(result.type === "null" || (result.type === "boolean" && !result.value))
    return {
      pass,
      message: () =>
        pass
          ? `Expected value NOT to be truthy, but it was: ${formatValue(result)}`
          : `Expected value to be truthy, but received ${formatValue(result)}`,
    }
  },
  async toBeFalsy(this: void, received: unknown) {
    const bytecode = typeof received === "string" || Array.isArray(received) ? toBytecode(received as string | any[]) : received as Bytecode
    const result = await run(bytecode)
    // ReefVM semantics: only null and false are falsy
    const pass = result.type === "null" || (result.type === "boolean" && !result.value)
    return {
      pass,
      message: () =>
        pass
          ? `Expected value NOT to be falsy, but it was: ${formatValue(result)}`
          : `Expected value to be falsy, but received ${formatValue(result)}`,
    }
  },
 })
 function formatValue(value: Value): string {
  switch (value.type) {
    case "null":
      return "null"
    case "boolean":
    case "number":
      return String(value.value)
    case "string":
      return `"${value.value}"`
    case "array":
      return `[${value.value.map(formatValue).join(", ")}]`
    case "dict": {
      const entries = Array.from(value.value.entries())
        .map(([k, v]) => `${k}: ${formatValue(v)}`)
        .join(", ")
      return `{${entries}}`
    }
    case "regex":
      return String(value.value)
    case "function":
    case "native":
      return "<function>"
    default:
      return String(value)
  }
 }
--- a/tests/validator.test.ts
+++ b/tests/validator.test.ts
@ -201,17 +201,17 @@ test("formatValidationErrors produces readable output", () => {
  expect(formatted).toContain("UNKNOWN")
 })
-test("detects JUMP without .label", () => {
+test("detects JUMP without # or .label", () => {
  const source = `
    JUMP 5
    HALT
  `
  const result = validateBytecode(source)
  expect(result.valid).toBe(false)
-  expect(result.errors[0]!.message).toContain("JUMP requires label (.label)")
+  expect(result.errors[0]!.message).toContain("JUMP requires immediate (#number) or label (.label)")
 })
-test("detects JUMP_IF_TRUE without .label", () => {
+test("detects JUMP_IF_TRUE without # or .label", () => {
  const source = `
    PUSH true
    JUMP_IF_TRUE 2
@ -219,10 +219,10 @@ test("detects JUMP_IF_TRUE without .label", () => {
  `
  const result = validateBytecode(source)
  expect(result.valid).toBe(false)
-  expect(result.errors[0]!.message).toContain("JUMP_IF_TRUE requires label (.label)")
+  expect(result.errors[0]!.message).toContain("JUMP_IF_TRUE requires immediate (#number) or label (.label)")
 })
-test("detects JUMP_IF_FALSE without .label", () => {
+test("detects JUMP_IF_FALSE without # or .label", () => {
  const source = `
    PUSH false
    JUMP_IF_FALSE 2
@ -230,18 +230,17 @@ test("detects JUMP_IF_FALSE without .label", () => {
  `
  const result = validateBytecode(source)
  expect(result.valid).toBe(false)
-  expect(result.errors[0]!.message).toContain("JUMP_IF_FALSE requires label (.label)")
+  expect(result.errors[0]!.message).toContain("JUMP_IF_FALSE requires immediate (#number) or label (.label)")
 })
-test("rejects JUMP with immediate number", () => {
+test("allows JUMP with immediate number", () => {
  const source = `
    JUMP #2
    PUSH 999
    HALT
  `
  const result = validateBytecode(source)
-  expect(result.valid).toBe(false)
+  expect(result.valid).toBe(true)
  expect(result.errors[0]!.message).toContain("JUMP requires label (.label)")
 })
 test("detects MAKE_ARRAY without #", () => {
--- a/tests/value.test.ts
+++ b/tests/value.test.ts
@ -1,302 +0,0 @@
 import { test, expect } from "bun:test"
 import { isValue, toValue } from "#reef"
 test("isValue - recognizes valid Value objects", () => {
  expect(isValue({ type: 'number', value: 42 })).toBe(true)
  expect(isValue({ type: 'number', value: 0 })).toBe(true)
  expect(isValue({ type: 'string', value: 'hello' })).toBe(true)
  expect(isValue({ type: 'string', value: '' })).toBe(true)
  expect(isValue({ type: 'boolean', value: true })).toBe(true)
  expect(isValue({ type: 'boolean', value: false })).toBe(true)
  expect(isValue({ type: 'null', value: null })).toBe(true)
  expect(isValue({ type: 'array', value: [] })).toBe(true)
  expect(isValue({ type: 'array', value: [toValue(1), toValue(2)] })).toBe(true)
  expect(isValue({ type: 'dict', value: new Map() })).toBe(true)
  expect(isValue({ type: 'regex', value: /test/ })).toBe(true)
  expect(isValue({
    type: 'function',
    value: '<function>',
    params: [],
    defaults: {},
    body: 0,
    variadic: false,
    named: false,
    parentScope: null as any
  })).toBe(true)
  expect(isValue({
    type: 'native',
    value: '<function>',
    fn: (() => { }) as any
  })).toBe(true)
 })
 test("isValue - rejects primitives", () => {
  expect(isValue(42)).toBe(false)
  expect(isValue(0)).toBe(false)
  expect(isValue('hello')).toBe(false)
  expect(isValue('')).toBe(false)
  expect(isValue(true)).toBe(false)
  expect(isValue(false)).toBe(false)
  expect(isValue(null)).toBe(false)
  expect(isValue(undefined)).toBe(false)
 })
 test("isValue - rejects plain objects", () => {
  expect(isValue({})).toBe(false)
  expect(isValue({ foo: 'bar' })).toBe(false)
  expect(isValue({ type: 'number' })).toBe(false)
  expect(isValue({ value: 42 })).toBe(false)
 })
 test("isValue - rejects arrays and functions", () => {
  expect(isValue([])).toBe(false)
  expect(isValue([1, 2, 3])).toBe(false)
  expect(isValue(() => { })).toBe(false)
  expect(isValue(function () { })).toBe(false)
 })
 test("isValue - rejects other object types", () => {
  expect(isValue(new Date())).toBe(false)
  expect(isValue(/regex/)).toBe(false)
  expect(isValue(new Map())).toBe(false)
  expect(isValue(new Set())).toBe(false)
 })
 test("isValue - used by toValue to detect already-converted values", () => {
  const value = toValue(42)
  expect(isValue(value)).toBe(true)
  const result = toValue(value)
  expect(result).toBe(value)
 })
 test("isValue - edge cases with type and value properties", () => {
  expect(isValue({ type: 'number', value: 42, extra: 'data' })).toBe(true)
  expect(isValue({ type: null, value: 42 })).toBe(false)
  expect(isValue({ type: 'number', value: undefined })).toBe(true)
  expect(isValue({ type: 'number', val: 42 })).toBe(false)
  expect(isValue({ typ: 'number', value: 42 })).toBe(false)
 })
 test("isValue - rejects objects with invalid type values", () => {
  expect(isValue({ type: 'text', value: 'Bob' })).toBe(false)
  expect(isValue({ type: 'email', value: 'test@example.com' })).toBe(false)
  expect(isValue({ type: 'password', value: 'secret' })).toBe(false)
  expect(isValue({ type: 'checkbox', value: true })).toBe(false)
  expect(isValue({ type: 'custom', value: 123 })).toBe(false)
  expect(isValue({ type: 'unknown', value: null })).toBe(false)
 })
 test("toValue - correctly handles HTML input props", async () => {
  const { VM, toBytecode, toValue } = await import("#reef")
  const bytecode = toBytecode([["HALT"]])
  const vm = new VM(bytecode)
  const inputProps = { type: 'text', value: 'Bob' }
  const converted = toValue(inputProps, vm)
  expect(converted.type).toBe('dict')
  expect(converted.value.get('type')).toEqual({ type: 'string', value: 'text' })
  expect(converted.value.get('value')).toEqual({ type: 'string', value: 'Bob' })
 })
 test("toValue - converts wrapped Reef functions back to original Value", async () => {
  const { VM, toBytecode, fnFromValue } = await import("#reef")
  // Create a Reef function
  const bytecode = toBytecode([
    ["MAKE_FUNCTION", ["x"], ".body"],
    ["STORE", "add1"],
    ["JUMP", ".end"],
    [".body:"],
    ["LOAD", "x"],
    ["PUSH", 1],
    ["ADD"],
    ["RETURN"],
    [".end:"],
    ["HALT"]
  ])
  const vm = new VM(bytecode)
  await vm.run()
  const reefFunction = vm.scope.get("add1")!
  expect(reefFunction.type).toBe("function")
  // Convert to JS function
  const jsFunction = fnFromValue(reefFunction, vm)
  expect(typeof jsFunction).toBe("function")
  // Convert back to Value - should return the original Reef function
  const backToValue = toValue(jsFunction)
  expect(backToValue).toBe(reefFunction)  // Same reference
  expect(backToValue.type).toBe("function")
 })
 test("fromValue - converts native function back to original JS function", async () => {
  const { VM, toBytecode, toValue, fromValue } = await import("#reef")
  const bytecode = toBytecode([["HALT"]])
  const vm = new VM(bytecode)
  // Create a native JS function
  const originalFn = (x: number, y: number) => x * y
  // Convert to Value (wraps it as a native function)
  const nativeValue = toValue(originalFn, vm)
  expect(nativeValue.type).toBe("native")
  // Convert back to JS - should get the original function
  const convertedFn = fromValue(nativeValue, vm)
  expect(typeof convertedFn).toBe("function")
  // Verify it's the same function
  expect(convertedFn).toBe(originalFn)
  // Verify it works correctly
  expect(convertedFn(3, 4)).toBe(12)
 })
 test("fromValue - native function roundtrip preserves functionality", async () => {
  const { VM, toBytecode, toValue, fromValue } = await import("#reef")
  const bytecode = toBytecode([["HALT"]])
  const vm = new VM(bytecode)
  // Create a native function with state
  let callCount = 0
  const countingFn = (n: number) => {
    callCount++
    return n * callCount
  }
  // Roundtrip through Value
  const nativeValue = toValue(countingFn, vm)
  const roundtrippedFn = fromValue(nativeValue, vm)
  // Verify it maintains state across calls
  expect(roundtrippedFn(10)).toBe(10)  // 10 * 1
  expect(roundtrippedFn(10)).toBe(20)  // 10 * 2
  expect(roundtrippedFn(10)).toBe(30)  // 10 * 3
  expect(callCount).toBe(3)
 })
 test("fromValue - async native function roundtrip", async () => {
  const { VM, toBytecode, toValue, fromValue } = await import("#reef")
  const bytecode = toBytecode([["HALT"]])
  const vm = new VM(bytecode)
  const asyncFn = async (x: number, y: number) => {
    await new Promise(resolve => setTimeout(resolve, 1))
    return x + y
  }
  const nativeValue = toValue(asyncFn, vm)
  expect(nativeValue.type).toBe("native")
  const roundtrippedFn = fromValue(nativeValue, vm)
  const result = await roundtrippedFn(5, 7)
  expect(result).toBe(12)
 })
 test("toValue - throws helpful error when calling function converted without VM", async () => {
  function myFunction(x: number) {
    return x * 2
  }
  const value = toValue(myFunction)
  expect(value.type).toBe('native')
  // Error is thrown when calling the function, not when converting
  await expect(async () => {
    await value.fn({ type: 'number', value: 5 })
  }).toThrow(/can't call function that was converted without a vm/)
  await expect(async () => {
    await value.fn({ type: 'number', value: 5 })
  }).toThrow(/Function: myFunction/)
  await expect(async () => {
    await value.fn({ type: 'number', value: 5 })
  }).toThrow(/Source:/)
  await expect(async () => {
    await value.fn({ type: 'number', value: 5 })
  }).toThrow(/Called from:/)
 })
 test("toValue - error message shows function info for arrow functions", async () => {
  const anonymousFn = (x: number) => x * 2
  const value = toValue(anonymousFn)
  expect(value.type).toBe('native')
  // Arrow functions show as <anonymous>
  await expect(async () => {
    await value.fn({ type: 'number', value: 5 })
  }).toThrow(/Function: <anonymous>/)
  await expect(async () => {
    await value.fn({ type: 'number', value: 5 })
  }).toThrow(/Source:/)
 })
 test("toValue - error when function is nested in object without VM", async () => {
  const obj = {
    name: "test",
    handler: (x: number) => x * 2
  }
  const value = toValue(obj)
  expect(value.type).toBe('dict')
  const handlerValue = value.value.get('handler')!
  expect(handlerValue.type).toBe('native')
  await expect(async () => {
    await (handlerValue as any).fn({ type: 'number', value: 5 })
  }).toThrow(/can't call function that was converted without a vm/)
  await expect(async () => {
    await (handlerValue as any).fn({ type: 'number', value: 5 })
  }).toThrow(/Function: handler/)
 })
 test("toValue - error when function is nested in array without VM", async () => {
  const arr = [1, 2, (x: number) => x * 2]
  const value = toValue(arr)
  expect(value.type).toBe('array')
  const fnValue = value.value[2]!
  expect(fnValue.type).toBe('native')
  await expect(async () => {
    await (fnValue as any).fn({ type: 'number', value: 5 })
  }).toThrow(/can't call function that was converted without a vm/)
 })
 test("fromValue - throws helpful error when converting function without VM", async () => {
  const { Scope, fromValue } = await import("#reef")
  const reefFunction = {
    type: 'function' as const,
    params: ['x', 'y'],
    defaults: {},
    body: 10,
    parentScope: new Scope(),
    variadic: false,
    named: false,
    value: '<function>' as const
  }
  expect(() => fromValue(reefFunction)).toThrow(/VM is required for function conversion/)
  expect(() => fromValue(reefFunction)).toThrow(/Function params: \[x, y\]/)
  expect(() => fromValue(reefFunction)).toThrow(/Function body at instruction: 10/)
  expect(() => fromValue(reefFunction)).toThrow(/Called from:/)
 })
--- a/tests/vm.test.ts
+++ b/tests/vm.test.ts
@ -1,54 +0,0 @@
 import { test, expect, describe } from "bun:test"
 import { VM } from "#vm"
 import { toBytecode } from "#bytecode"
 import { toValue } from "#value"
 describe("VM scope methods", () => {
  test("pushScope creates isolated child scope", async () => {
    const bytecode = toBytecode([["HALT"]])
    const vm = new VM(bytecode)
    vm.set("x", 42)
    vm.pushScope()
    const xValue = vm.scope.get("x")
    expect(xValue).toEqual({ type: "number", value: 42 })
    vm.set("y", 100)
    expect(vm.scope.get("x")).toEqual({ type: "number", value: 42 })
    expect(vm.scope.get("y")).toEqual({ type: "number", value: 100 })
  })
  test("popScope returns to parent scope and child variables are not accessible", async () => {
    const bytecode = toBytecode([["HALT"]])
    const vm = new VM(bytecode)
    vm.set("x", 42)
    vm.pushScope()
    vm.set("y", 100)
    expect(vm.scope.get("x")).toEqual({ type: "number", value: 42 })
    expect(vm.scope.get("y")).toEqual({ type: "number", value: 100 })
    vm.popScope()
    expect(vm.scope.get("x")).toEqual({ type: "number", value: 42 })
    expect(vm.scope.get("y")).toBeUndefined()
  })
  test("pushScope with locals initializes child scope with variables", async () => {
    const bytecode = toBytecode([["HALT"]])
    const vm = new VM(bytecode)
    vm.set("x", 42)
    vm.pushScope({ y: 100, z: "hello" })
    expect(vm.scope.get("x")).toEqual({ type: "number", value: 42 })
    expect(vm.scope.get("y")).toEqual({ type: "number", value: 100 })
    expect(vm.scope.get("z")).toEqual({ type: "string", value: "hello" })
    vm.popScope()
    expect(vm.scope.get("x")).toEqual({ type: "number", value: 42 })
    expect(vm.scope.get("y")).toBeUndefined()
    expect(vm.scope.get("z")).toBeUndefined()
  })
 })