eclectic-pencil LogiqueWerks blog

In JavaScript and other prototype-based languages it is very natural to extend an object.

In Rebol it is only slightly less obvious.

Much like using the object-literal notation or JSON in JavaScript, it is not necessary to use an explicit reference to Object. An object in Rebol is much more like a record in Oz which can reference functions as first-class objects.

But if we do want an object as a prototype from which to construct other objects, then we use

my-obj: make object! [answer: 42 question: "unknown"]

When it comes time to extend my-obj there are at least two options:
my-obj: make my-obj [my-extension: "worm-hole"]
We can see the new attribute by using probe

probe my-obj

The alternative would have been

my-obj: make my-obj append [my-extension2: "black-hole"] [] ; note the empty block

To use my-obj as a protoytpe is to use make

my-derived-obj: make my-obj [another-extension: "not derived"]
probe my-derived-obj

In Rebol3 we may have the option to simply extend a prototype as we now do in JavaScript or Io