functions with bindings

compiler/compiler_test.go

@@ -591,6 +591,80 @@ func TestFunctionCalls(t *testing.T) {
 	runCompilerTests(t, tests)
 }
 
+func TestLetStatementScopes(t *testing.T) {
+	tests := []compilerTestCase{
+		{
+			input: `
+            let num = 55;
+            fn() { num }
+            `,
+			expectedConstants: []interface{}{
+				55,
+				[]code.Instructions{
+					code.Make(code.OpGetGlobal, 0),
+					code.Make(code.OpReturnValue),
+				},
+			},
+			expectedInstructions: []code.Instructions{
+				code.Make(code.OpConstant, 0),
+				code.Make(code.OpSetGlobal, 0),
+				code.Make(code.OpConstant, 1),
+				code.Make(code.OpPop),
+			},
+		},
+		{
+			input: `
+            fn() {
+                let num = 55;
+                num
+            }
+            `,
+			expectedConstants: []interface{}{
+				55,
+				[]code.Instructions{
+					code.Make(code.OpConstant, 0),
+					code.Make(code.OpSetLocal, 0),
+					code.Make(code.OpGetLocal, 0),
+					code.Make(code.OpReturnValue),
+				},
+			},
+			expectedInstructions: []code.Instructions{
+				code.Make(code.OpConstant, 1),
+				code.Make(code.OpPop),
+			},
+		},
+		{
+			input: `
+            fn() {
+                let a = 55;
+                let b = 77;
+                a + b
+            }
+            `,
+			expectedConstants: []interface{}{
+				55,
+				77,
+				[]code.Instructions{
+					code.Make(code.OpConstant, 0),
+					code.Make(code.OpSetLocal, 0),
+					code.Make(code.OpConstant, 1),
+					code.Make(code.OpSetLocal, 1),
+					code.Make(code.OpGetLocal, 0),
+					code.Make(code.OpGetLocal, 1),
+					code.Make(code.OpAdd),
+					code.Make(code.OpReturnValue),
+				},
+			},
+			expectedInstructions: []code.Instructions{
+				code.Make(code.OpConstant, 2),
+				code.Make(code.OpPop),
+			},
+		},
+	}
+
+	runCompilerTests(t, tests)
+}
+
 func runCompilerTests(t *testing.T, tests []compilerTestCase) {
 	t.Helper()