debug

vm/vm.go

@@ -2,9 +2,11 @@ package vm
 
 import (
 	"fmt"
+	"log"
 	"monkey/code"
 	"monkey/compiler"
 	"monkey/object"
+	"strings"
 )
 
 const StackSize = 2048
@@ -16,6 +18,8 @@ var True = &object.Boolean{Value: true}
 var False = &object.Boolean{Value: false}
 
 type VM struct {
+	Debug bool
+
 	constants []object.Object
 
 	stack []object.Object
@@ -77,6 +81,17 @@ func (vm *VM) Run() error {
 	var ins code.Instructions
 	var op code.Opcode
 
+	if vm.Debug {
+		log.Printf(
+			"%-20s %-20s\n",
+			strings.Split(ins[ip:].String(), "\n")[0],
+			fmt.Sprintf(
+				"[ip=%02d fp=%02d, sp=%02d]",
+				ip, vm.sp, vm.framesIndex-1,
+			),
+		)
+	}
+
 	for vm.currentFrame().ip < len(vm.currentFrame().Instructions())-1 {
 		vm.currentFrame().ip++