Second Degree Homoiconicity

Is ComaLisp homoiconic?

I wish it is, so I did some research to see if I can argue that it is. (If I can argue that it is already homoiconic, then I don’t have to work to make it so).

The origin of the term is from TRAC,

Because TRAC procedures and text have the same representation inside and outside the processor, the term homoiconic is applicable, from homo meaning the same, and icon meaning representation.

By this definition, ComaLisp is not homoiconic, because the Ruby interpreter executes AST, not the source text. However, with some work, ComaLisp could be second degree homoiconic.

There is the gem LiveAst. It can turn a method or block into AST. It also adds Kernel#ast_eval. With LiveAst, we can achieve 2nd-degree homoiconicity in Ruby,

Text => AST => Interpreter => AST => Text

Whereas a conventional Lisp would be 1st-degree homoiconic, i.e.,

AST => Interpreter => AST

Is Thinking Homoiconic?

If the “stuff” of thought is the same as thought itself, then it is 1st-degree homoiconic. But if language is an intermediary of thought, and thought itself is a meta-language (see Jackendoff), then the it is 2nd-degree homoiconic.

Discuss on Hacker News.

If you like my writing you should follow me on Twitter.