restructure project

internal/builtins/writefile.go

@@ -0,0 +1,28 @@
+package builtins
+
+import (
+	"io/ioutil"
+	"monkey/internal/object"
+	"monkey/internal/typing"
+)
+
+// WriteFile ...
+func WriteFile(args ...object.Object) object.Object {
+	if err := typing.Check(
+		"writefile", args,
+		typing.ExactArgs(2),
+		typing.WithTypes(object.STRING_OBJ, object.STRING_OBJ),
+	); err != nil {
+		return newError(err.Error())
+	}
+
+	filename := args[0].(*object.String).Value
+	data := []byte(args[1].(*object.String).Value)
+
+	err := ioutil.WriteFile(filename, data, 0755)
+	if err != nil {
+		return newError("IOError: error writing file %s: %s", filename, err)
+	}
+
+	return &object.Null{}
+}