core.match gotcha
I've recently started using core.match, which has been quite pleasant and successful; thank you to David Nolen, and all others that have contributed. The only hiccup I've had has been around how core.match incorporates bindings from local scope into pattern rows. A stupid example demonstrating the (potential) confusion: = (match [[:k]] [[x]] x) :k vs. = (let [x 12] (match [[:k]] [[x]] x)) nil I was assuming that bindings established by the wildcards in pattern rows shadowed any other local bindings. It took me a while to realize that, e.g. in the example above, `x` was being interpolated into `[[x]]` to yield a pattern row of `[[12]]`. Now that I know that, all's well; but, it took me perhaps longer than it should have to figure it out. All this is to say, perhaps a relevant note in the (really excellent) overview wiki page[1] might be helpful. Thanks, - Chas [1] https://github.com/clojure/core.match/wiki/Overview -- You received this message because you are subscribed to the Google Groups Clojure group. To post to this group, send email to clojure@googlegroups.com Note that posts from new members are moderated - please be patient with your first post. To unsubscribe from this group, send email to clojure+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/clojure?hl=en
Re: core.match gotcha
On Jan 6, 2013, at 10:48 AM, Ambrose Bonnaire-Sergeant wrote: On a related note, combining a quoted symbol and a named wildcard pattern seems to be buggy. clojure.core.match= (match 'my-sym a a) #CompilerException java.lang.RuntimeException: Unable to resolve symbol: ocr-3612 in this context, compiling:(REPL:79) clojure.core.match= (macroexpand-1 '(match 'my-sym a a)) (clojure.core/let [a ocr-3620] a) Yeah, I've hit that, but presumed I was just doing something wrong. :-) I included a section on how symbols work as patterns. Perfect, reads very well. I'm glad I didn't just add something, it would not have been as clear or succinct. Interestingly, the old design page still has some good stuff, including an explanation of this particular issue. I'm not sure how much is still relevant. https://github.com/clojure/core.match/wiki/Design-Wiki Ach, I hadn't thought to look at what else might be lurking in the wiki! The 'Local Bindings' section on the design page would have made it all obvious. Thanks! - Chas -- You received this message because you are subscribed to the Google Groups Clojure group. To post to this group, send email to clojure@googlegroups.com Note that posts from new members are moderated - please be patient with your first post. To unsubscribe from this group, send email to clojure+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/clojure?hl=en
Re: core.match gotcha
On Jan 6, 10:48 am, Ambrose Bonnaire-Sergeant abonnaireserge...@gmail.com wrote: On a related note, combining a quoted symbol and a named wildcard pattern seems to be buggy. clojure.core.match= (match 'my-sym a a) #CompilerException java.lang.RuntimeException: Unable to resolve symbol: ocr-3612 in this context, compiling:(REPL:79) clojure.core.match= (macroexpand-1 '(match 'my-sym a a)) (clojure.core/let [a ocr-3620] a) Ticket opened here FWIW: http://dev.clojure.org/jira/browse/MATCH-66 - Chas -- You received this message because you are subscribed to the Google Groups Clojure group. To post to this group, send email to clojure@googlegroups.com Note that posts from new members are moderated - please be patient with your first post. To unsubscribe from this group, send email to clojure+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/clojure?hl=en
