Hi list! I see I didn't send my reply to Zach into a iterate-devel mailing list, by omission. I think now it is the time to correct that. ---------- Forwarded message ---------- From: Denis Budyak <budden73@gmail.com> Date: Tue, 16 Oct 2012 11:06:34 +0400 Subject: Re: [iterate-devel] using keywords in clauses To: Zach <zach.smith@colorado.edu> Hi Zach, list!
If you encode FOR and COLLECT as special tokens that Iterate's parser/compiler just understands you break the extensibility. Iterate-keywords makes minimal change to iterate. Roughly, it makes (defsynonym :any-clause-head any-clause-head), but only for standard iterate clauses, not for user defined. As synonyms do not work with special clauses like (next-iteration) (it can be considered a bug in synonym mechanism), patch to iterate itself was required.
Consequently, it does not break your example. %(iterate-keywors:iter (test:for i in-whole-vector #(1 3)) (:collect i)) (1 3) %(iterate-keywors:iter (:for i in-whole-vector #(1 3)) (:collect i)) ...errs... For is intended to be extensible via second keyword, in-whole-vector in our case. If we define it as in manual, %(in-package :iterate-keywords) %(defmacro-clause (FOR var IN-WHOLE-VECTOR v) ...), It will work with iterate-keywords as intended: %(in-package:cl-user) %(iterate-keywords:iter (:for i in-whole-vector #(1 3)) (:collect i)) (1 3) If we define any new clause, iterate-keywords won't touch it. We can define it in :test package and use the symbol from that package, that is, %(iter (test:our-clause)) Additionally, we can make %(defsynonym :our-clause test:our-clause) and thus enable ourselves to use keyword: %(iter (:our-clause))
and even then, it would suffer from name collisions inherent in the keyword package Most of iterate keywords are in a keyword package already as they are used in common lisp loop macro. What kind of collision do you mean?