"I have a mind like a steel... uh... thingy." Patrick Logan's weblog.

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Friday, January 14, 2005

The Io Programming Language

A friend has been playing with the language Io. I spent an hour or so with him on it. Very interesting.

Io is small prototype-based programming language. The ideas in Io are mostly inspired by Smalltalk (all values are objects), Self, NewtonScript and Act1 (prototype-based differential inheritance, actors and futures for concurrency), LISP (code is a runtime inspectable/modifiable tree) and Lua (small, embeddable).
The language has an interesting evaluation, reflection, and delegation model. Io has a syntax that does not always require an explicitly denoted receiver for a message. Someone just learning Io can scratch their head once or twice figuring out what's going on.

On the whole though Io is a very simple language with what looks like a simple CPython-like implementation. For programmers looking to understand the "prototypes and delegation" approach to object-oriented programming (as opposed to "classes and inheritance"), then Io seems to be a simple way to dive in deep.

Playing a bit with Io felt a lot like the pre-CLOS days of Lisp in the 1980s when there were a lot of experiments with object systems like ObjVLisp, OakLisp, Loops, etc.

3 comments:

Ian Bicking said...

I've never had a chance to really use prototype-based programming, only reading about it from afar. But I'm starting to think my desire for a alternative to the "class" keyword in Python is actually a desire for prototype-based programming.

Isaac Gouy said...

And then there's JavaScript

http://www.mozilla.org/rhino/scopes.html

Anonymous said...

hi, if you have used Javascript, then you have used
a prototype based language :-) Look at the .prototype
slot on objects in JS, and you'll find the essence of a
prototype based language.

drudru

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Portland, Oregon, United States
I'm usually writing from my favorite location on the planet, the pacific northwest of the u.s. I write for myself only and unless otherwise specified my posts here should not be taken as representing an official position of my employer. Contact me at my gee mail account, username patrickdlogan.