pushScope accepts locals

src/vm.ts

@@ -60,8 +60,12 @@ export class VM {
     this.scope.set(name, { type: 'native', fn, value: '<function>' })
   }
 
-  pushScope() {
+  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() {

tests/vm.test.ts

@@ -9,14 +9,12 @@ describe("VM scope methods", () => {
     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 })
   })
@@ -26,7 +24,6 @@ describe("VM scope methods", () => {
     const vm = new VM(bytecode)
 
     vm.set("x", 42)
-
     vm.pushScope()
     vm.set("y", 100)
 
@@ -34,9 +31,24 @@ describe("VM scope methods", () => {
     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()
+  })
 })