ReefVM/tests/functions.test.ts

import { test, expect } from "bun:test"
import { toBytecode } from "#bytecode"
import { toValue, run } from "#reef"

test("MAKE_FUNCTION - creates function with captured scope", async () => {
  const bytecode = toBytecode(`
    MAKE_FUNCTION () #999
  `)

  const result = await run(bytecode)
  expect(result.type).toBe('function')
  if (result.type === 'function') {
    expect(result.body).toBe(999)
    expect(result.params).toEqual([])
  }
})

test("CALL and RETURN - basic function call", async () => {
  const bytecode = toBytecode(`
    MAKE_FUNCTION () #5
    PUSH 0
    PUSH 0
    CALL
    HALT
    PUSH 42
    RETURN
  `)

  const result = await run(bytecode)
  expect(result).toEqual({ type: 'number', value: 42 })
})

test("CALL and RETURN - function with one parameter", async () => {
  const bytecode = toBytecode(`
    MAKE_FUNCTION (x) #6
    PUSH 100
    PUSH 1
    PUSH 0
    CALL
    HALT
    LOAD x
    RETURN
  `)

  const result = await run(bytecode)
  expect(result).toEqual({ type: 'number', value: 100 })
})

test("CALL and RETURN - function with two parameters", async () => {
  const bytecode = toBytecode(`
    MAKE_FUNCTION (a b) #7
    PUSH 10
    PUSH 20
    PUSH 2
    PUSH 0
    CALL
    HALT
    LOAD a
    LOAD b
    ADD
    RETURN
  `)

  const result = await run(bytecode)
  expect(result).toEqual({ type: 'number', value: 30 })
})

test("CALL - variadic function with no fixed params", async () => {
  const bytecode = toBytecode(`
    MAKE_FUNCTION (...args) #8
    PUSH 1
    PUSH 2
    PUSH 3
    PUSH 3
    PUSH 0
    CALL
    HALT
    LOAD args
    RETURN
  `)

  const result = await run(bytecode)
  expect(result).toEqual({
    type: 'array',
    value: [
      { type: 'number', value: 1 },
      { type: 'number', value: 2 },
      { type: 'number', value: 3 }
    ]
  })
})

test("CALL - variadic function with one fixed param", async () => {
  const bytecode = toBytecode(`
    MAKE_FUNCTION (x ...rest) #8
    PUSH 10
    PUSH 20
    PUSH 30
    PUSH 3
    PUSH 0
    CALL
    HALT
    LOAD rest
    RETURN
  `)

  const result = await run(bytecode)
  // x should be 10, rest should be [20, 30]
  expect(result).toEqual({
    type: 'array',
    value: [
      { type: 'number', value: 20 },
      { type: 'number', value: 30 }
    ]
  })
})

test("CALL - variadic function with two fixed params", async () => {
  const bytecode = toBytecode(`
    MAKE_FUNCTION (a b ...rest) #9
    PUSH 1
    PUSH 2
    PUSH 3
    PUSH 4
    PUSH 4
    PUSH 0
    CALL
    HALT
    LOAD rest
    RETURN
  `)

  const result = await run(bytecode)
  // a=1, b=2, rest=[3, 4]
  expect(result).toEqual({
    type: 'array',
    value: [
      { type: 'number', value: 3 },
      { type: 'number', value: 4 }
    ]
  })
})

test("CALL - variadic function with no extra args", async () => {
  const bytecode = toBytecode(`
    MAKE_FUNCTION (x ...rest) #6
    PUSH 10
    PUSH 1
    PUSH 0
    CALL
    HALT
    LOAD rest
    RETURN
  `)

  const result = await run(bytecode)
  // rest should be empty array
  expect(result).toEqual({ type: 'array', value: [] })
})

test("CALL - variadic function with defaults on fixed params", async () => {
  const bytecode = toBytecode(`
    MAKE_FUNCTION (x=5 ...rest) #5
    PUSH 0
    PUSH 0
    CALL
    HALT
    LOAD x
    RETURN
  `)

  const result = await run(bytecode)
  // x should use default value 5
  expect(result).toEqual({ type: 'number', value: 5 })
})

test("TAIL_CALL - variadic function", async () => {
  const bytecode = toBytecode(`
    MAKE_FUNCTION (x ...rest) #8
    PUSH 1
    PUSH 2
    PUSH 3
    PUSH 3
    PUSH 0
    CALL
    HALT
    LOAD rest
    RETURN
  `)

  const result = await run(bytecode)
  // Should return the rest array [2, 3]
  expect(result).toEqual({
    type: 'array',
    value: [
      { type: 'number', value: 2 },
      { type: 'number', value: 3 }
    ]
  })
})

test("CALL - named args function with no fixed params", async () => {
  const bytecode = toBytecode(`
    MAKE_FUNCTION (@named) #9
    PUSH "name"
    PUSH "Bob"
    PUSH "age"
    PUSH 50
    PUSH 0
    PUSH 2
    CALL
    HALT
    LOAD named
    RETURN
  `)

  const result = await run(bytecode)
  expect(result.type).toBe('dict')
  if (result.type === 'dict') {
    expect(result.value.get('name')).toEqual({ type: 'string', value: 'Bob' })
    expect(result.value.get('age')).toEqual({ type: 'number', value: 50 })
  }
})

test("CALL - named args function with one fixed param", async () => {
  const bytecode = toBytecode(`
    MAKE_FUNCTION (x @named) #8
    PUSH 10
    PUSH "name"
    PUSH "Alice"
    PUSH 1
    PUSH 1
    CALL
    HALT
    LOAD named
    RETURN
  `)

  const result = await run(bytecode)
  expect(result.type).toBe('dict')
  if (result.type === 'dict') {
    expect(result.value.get('name')).toEqual({ type: 'string', value: 'Alice' })
    expect(result.value.size).toBe(1)
  }
})

test("CALL - named args with matching param name should bind to param not named", async () => {
  const bytecode = toBytecode(`
    MAKE_FUNCTION (name @named) #8
    PUSH "Bob"
    PUSH "age"
    PUSH 50
    PUSH 1
    PUSH 1
    CALL
    HALT
    LOAD name
    RETURN
  `)

  const result = await run(bytecode)
  // name should be bound as regular param, not collected in named
  expect(result).toEqual({ type: 'string', value: 'Bob' })
})

test("CALL - named args that match param names should not be in named", async () => {
  const bytecode = toBytecode(`
    MAKE_FUNCTION (name age @named) #9
    PUSH "name"
    PUSH "Bob"
    PUSH "city"
    PUSH "NYC"
    PUSH 0
    PUSH 2
    CALL
    HALT
    LOAD named
    RETURN
  `)

  const result = await run(bytecode)
  expect(result.type).toBe('dict')
  if (result.type === 'dict') {
    // Only city should be in named, name should be bound to param
    expect(result.value.get('city')).toEqual({ type: 'string', value: 'NYC' })
    expect(result.value.has('name')).toBe(false)
    expect(result.value.size).toBe(1)
  }
})

test("CALL - mixed variadic and named args", async () => {
  const bytecode = toBytecode(`
    MAKE_FUNCTION (x ...rest @named) #10
    PUSH 1
    PUSH 2
    PUSH 3
    PUSH "name"
    PUSH "Bob"
    PUSH 3
    PUSH 1
    CALL
    HALT
    LOAD rest
    RETURN
  `)

  const result = await run(bytecode)
  // rest should have [2, 3]
  expect(result).toEqual({
    type: 'array',
    value: [
      { type: 'number', value: 2 },
      { type: 'number', value: 3 }
    ]
  })
})

test("CALL - mixed variadic and named args, check named", async () => {
  const bytecode = toBytecode(`
    MAKE_FUNCTION (x ...rest @named) #10
    PUSH 1
    PUSH 2
    PUSH 3
    PUSH "name"
    PUSH "Bob"
    PUSH 3
    PUSH 1
    CALL
    HALT
    LOAD named
    RETURN
  `)

  const result = await run(bytecode)
  expect(result.type).toBe('dict')
  if (result.type === 'dict') {
    expect(result.value.get('name')).toEqual({ type: 'string', value: 'Bob' })
  }
})

test("CALL - named args with no extra named args", async () => {
  const bytecode = toBytecode(`
    MAKE_FUNCTION (x @named) #6
    PUSH 10
    PUSH 1
    PUSH 0
    CALL
    HALT
    LOAD named
    RETURN
  `)

  const result = await run(bytecode)
  // named should be empty dict
  expect(result.type).toBe('dict')
  if (result.type === 'dict') {
    expect(result.value.size).toBe(0)
  }
})

test("CALL - named args with defaults on fixed params", async () => {
  const bytecode = toBytecode(`
    MAKE_FUNCTION (x=5 @named) #7
    PUSH "name"
    PUSH "Alice"
    PUSH 0
    PUSH 1
    CALL
    HALT
    LOAD x
    RETURN
  `)

  const result = await run(bytecode)
  // x should use default value 5
  expect(result).toEqual({ type: 'number', value: 5 })
})

test("CALL - fixed params can be named", async () => {
  const bytecode = toBytecode(`
    MAKE_FUNCTION (a b) .func_0
    STORE minus
    TRY_LOAD minus
    PUSH 200
    PUSH 'a'
    PUSH 900
    PUSH 1
    PUSH 1
    CALL
    HALT
    .func_0:
    TRY_LOAD a
    TRY_LOAD b
    SUB
    RETURN
  `)

  const result = await run(bytecode)
  expect(result).toEqual(toValue(700))
})

test("TRY_CALL - calls function if found", async () => {
  const bytecode = toBytecode([
    ["MAKE_FUNCTION", [], ".body"],
    ["STORE", "myFunc"],
    ["TRY_CALL", "myFunc"],
    ["HALT"],
    [".body:"],
    ["PUSH", 42],
    ["RETURN"]
  ])

  const result = await run(bytecode)
  expect(result).toEqual({ type: 'number', value: 42 })
})

test("TRY_CALL - pushes value if variable exists but is not a function", async () => {
  const bytecode = toBytecode([
    ["PUSH", 99],
    ["STORE", "myVar"],
    ["TRY_CALL", "myVar"],
    ["HALT"]
  ])

  const result = await run(bytecode)
  expect(result).toEqual({ type: 'number', value: 99 })
})

test("TRY_CALL - pushes string if variable not found", async () => {
  const bytecode = toBytecode([
    ["TRY_CALL", "unknownVar"],
    ["HALT"]
  ])

  const result = await run(bytecode)
  expect(result).toEqual({ type: 'string', value: 'unknownVar' })
})

test("TRY_CALL - handles arrays", async () => {
  const bytecode = toBytecode([
    ["PUSH", 1],
    ["PUSH", 2],
    ["MAKE_ARRAY", 2],
    ["STORE", "myArray"],
    ["TRY_CALL", "myArray"],
    ["HALT"]
  ])

  const result = await run(bytecode)
  expect(result.type).toBe('array')
  if (result.type === 'array') {
    expect(result.value).toEqual([
      { type: 'number', value: 1 },
      { type: 'number', value: 2 }
    ])
  }
})

test("TRY_CALL - handles dicts", async () => {
  const bytecode = toBytecode([
    ["PUSH", "key"],
    ["PUSH", "value"],
    ["MAKE_DICT", 1],
    ["STORE", "myDict"],
    ["TRY_CALL", "myDict"],
    ["HALT"]
  ])

  const result = await run(bytecode)
  expect(result.type).toBe('dict')
  if (result.type === 'dict') {
    expect(result.value.get('key')).toEqual({ type: 'string', value: 'value' })
  }
})

test("TRY_CALL - handles null values", async () => {
  const bytecode = toBytecode([
    ["PUSH", null],
    ["STORE", "myNull"],
    ["TRY_CALL", "myNull"],
    ["HALT"]
  ])

  const result = await run(bytecode)
  expect(result).toEqual({ type: 'null', value: null })
})

test("TRY_CALL - function can access its parameters", async () => {
  const bytecode = toBytecode([
    ["MAKE_FUNCTION", ["x"], ".body"],
    ["STORE", "addFive"],
    ["PUSH", 10],
    ["STORE", "x"],
    ["TRY_CALL", "addFive"],
    ["HALT"],
    [".body:"],
    ["LOAD", "x"],
    ["PUSH", 5],
    ["ADD"],
    ["RETURN"]
  ])

  const result = await run(bytecode)
  // Function is called with 0 args, so x inside function should be null
  // Then we add 5 to null (which coerces to 0)
  expect(result).toEqual({ type: 'number', value: 5 })
})

test("TRY_CALL - with string format", async () => {
  const bytecode = toBytecode(`
    MAKE_FUNCTION () #4
    STORE myFunc
    TRY_CALL myFunc
    HALT
    PUSH 100
    RETURN
  `)

  const result = await run(bytecode)
  expect(result).toEqual({ type: 'number', value: 100 })
})