"Diogo F. S. Ramos" <d...@riseup.net> writes: > The documentation is already pointing out that some characters are > special, so adding the "non-greedy" observation is not special in this > case and IMO it's an expected feature from regexps.
I'd rather say that *both* the mention of those characters, and the mention of non-greediness being unsupported, are special cases. :-) Maybe we should just remove both and only provide a link to the specification of POSIX ERE, or clarify that "POSIX extended regular expressions" are a specific type of regexp (and not the possible misinterpretation which is "an (ad-hoc) extended version of POSIX regexps") so that users can search for documentation on them by themselves. (Many Unix-like systems have a man-page for regexps; IIRC GNU+Linux distros tend to have a "regex" man-page which describe both POSIX BRE (Basic RE) and ERE, and I see the three BSDs all have an "re_format" man-page (linked to by the regex(3) man-page) which also describes those two.) By the way I see that the mention of POSIX ERE happens only in section 6.15.1 and not directly in the intro 6.15, which instead misleadingly links to Emacs regexps. Also, I never expect non-greediness support from regexps, because I've "grown up" as a Unix-like OS user and shell scripter, so it's POSIX BRE (sed, grep) and ERE (grep, awk) for me. This probably goes for many people. > Your observation makes me think I didn't go far enough. If users > expect Perl regexps, we should warn them that Guile's is not. > > Ultimately, I think Guile should document its own regexp syntax. Like I said, "POSIX ERE" is an absolute specification. We might still want to distribute a copy of it so users can access it more easily, but on the other hand the manual implies that the supported regexp format actually depends on what regexp library Guile was compiled with. (Or am I misinterpreting paragraph 2 of 6.15 plus paragraph 1 of 6.15.1 which says "by default"?) My proposal would be to remove the Emacs link in 6.15, add a paragraph that has a sole, clear mention of POSIX ERE, and remove the first paragraph of 6.15.1, or keep its first sentence because it's crucial information so the redundancy with the preceding section doesn't hurt. Taylan
