restructure project

internal/builtins/abs.go

@@ -0,0 +1,24 @@
+package builtins
+
+import (
+	"monkey/internal/object"
+	"monkey/internal/typing"
+)
+
+// Abs  ...
+func Abs(args ...object.Object) object.Object {
+	if err := typing.Check(
+		"abs", args,
+		typing.ExactArgs(1),
+		typing.WithTypes(object.INTEGER_OBJ),
+	); err != nil {
+		return newError(err.Error())
+	}
+
+	i := args[0].(*object.Integer)
+	value := i.Value
+	if value < 0 {
+		value = value * -1
+	}
+	return &object.Integer{Value: value}
+}