VM!

compiler/compiler.go

@@ -1,6 +1,7 @@
 package compiler
 
 import (
+	"fmt"
 	"monkey/ast"
 	"monkey/code"
 	"monkey/object"
@@ -45,6 +46,13 @@ func (c *Compiler) Compile(node ast.Node) error {
 			return err
 		}
 
+		switch node.Operator {
+		case "+":
+			c.emit(code.OpAdd)
+		default:
+			return fmt.Errorf("unknown operator %s", node.Operator)
+		}
+
 	case *ast.IntegerLiteral:
 		integer := &object.Integer{Value: node.Value}
 		c.emit(code.OpConstant, c.addConstant(integer))

compiler/compiler_test.go

@@ -24,6 +24,7 @@ func TestIntegerArithmetic(t *testing.T) {
 			expectedInstructions: []code.Instructions{
 				code.Make(code.OpConstant, 0),
 				code.Make(code.OpConstant, 1),
+				code.Make(code.OpAdd),
 			},
 		},
 	}