collect clause in progn in loop facility

Discussion of Common Lisp

collect clause in progn in loop facility

Postby jiyoo » Sun Sep 22, 2013 3:28 am

Suppose I have a loop form (using the loop facility) and within it is a do clause, and within the do clause is a let form, and somewhere deep within the let form are two collect clauses (like COLLECT .. INTO ..), except it's not a legal syntax to put collect clauses or any clauses in those positions. What are my options in this case?

If it were just one collect clause, I could instead put the entire let form inside a collect clause. Things seem tricky when there are two collect clauses.

I could turn the two collect clauses into two push forms but then I would be sort of reinventing the loop facility's collect feature.
Posts: 1
Joined: Wed Sep 11, 2013 12:26 am

Re: collect clause in progn in loop facility

Postby nuntius » Mon Sep 23, 2013 10:37 am

CL's LOOP can be a useful tool, but it is not fully general purpose. Many language purists find it to be an abomination. Many pragmatists find it to be beautiful despite its rough spots.

Recommendation: Value results over style. Only worry about style when bugs keep cropping up in the same section of ugly code. Then refactor that code, remembering to value results over style.

User avatar
Posts: 538
Joined: Sat Aug 09, 2008 10:44 am
Location: Newton, MA

Re: collect clause in progn in loop facility

Postby Goheeca » Mon Sep 23, 2013 12:26 pm

It's better to specify a particular snippet why do you need have collects in a let form than just saying. In this case I can only link you to loop that it has also intial and final clauses which with collect might be used in your issue.
cl-2dsyntax is my attempt to create a Python-like reader. My mirror of CLHS (and the dark themed version). Temporary mirrors of aferomentioned: CLHS and a dark version.
User avatar
Posts: 271
Joined: Thu May 10, 2012 12:54 pm

Return to Common Lisp

Who is online

Users browsing this forum: Bing [Bot] and 8 guests