feat: add support for builtin new (#125)

_test/new0.go

@@ -0,0 +1,10 @@
+package main
+
+func main() {
+	a := new(int)
+	*a = 3
+	println(*a)
+}
+
+// Output:
+// 3

interp/cfg.go

@@ -540,6 +540,9 @@ func (interp *Interpreter) Cfg(root *Node) ([]*Node, error) {
 					}
 					n.child[1].val = n.typ
 					n.child[1].kind = BasicLit
+				case "new":
+					n.typ, err = nodeType(interp, scope, n.child[1])
+					n.typ = &Type{cat: PtrT, val: n.typ}
 				case "recover":
 					n.typ = scope.getType("interface{}")
 				}

interp/interp.go

@@ -156,6 +156,7 @@ func initUniverse() *Scope {
 		"close":   &Symbol{kind: Bltn, builtin: _close},
 		"len":     &Symbol{kind: Bltn, builtin: _len},
 		"make":    &Symbol{kind: Bltn, builtin: _make},
+		"new":     &Symbol{kind: Bltn, builtin: _new},
 		"panic":   &Symbol{kind: Bltn, builtin: _panic},
 		"println": &Symbol{kind: Bltn, builtin: _println},
 		"recover": &Symbol{kind: Bltn, builtin: _recover},

interp/interp_test.go

@@ -3909,6 +3909,27 @@ func main() {
 	// -1
 }
 
+func Example_new0() {
+	src := `
+package main
+
+func main() {
+	a := new(int)
+	*a = 3
+	println(*a)
+}
+`
+	i := interp.New(interp.Opt{Entry: "main"})
+	i.Use(stdlib.Value)
+	_, err := i.Eval(src)
+	if err != nil {
+		panic(err)
+	}
+
+	// Output:
+	// 3
+}
+
 func Example_op0() {
 	src := `
 package main

interp/run.go

@@ -1321,6 +1321,17 @@ func _len(n *Node) {
 	}
 }
 
+func _new(n *Node) {
+	i := n.findex
+	next := getExec(n.tnext)
+	typ := n.child[1].typ.TypeOf()
+
+	n.exec = func(f *Frame) Builtin {
+		f.data[i] = reflect.New(typ)
+		return next
+	}
+}
+
 // _make allocates and initializes a slice, a map or a chan.
 func _make(n *Node) {
 	i := n.findex