-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 According to Gary V. Vaughan on 2/17/2008 2:07 AM:
Hi Gary, and thanks for a review of my ideas, plus some cool ones of your own. | | However (breaking my own rule about not introducing additional macros if | at all possible), I think list sorting and filtering are both useful enough | idioms that we should break them out into new builtins so that our users | needn't resort to the hackish things you mention below... which merely | highlight deficiencys in the current language implementation. Also, | m4symbols proper will be faster in the case where the order of returned | symbols is not important. So: | | -- Builtin (gnu): m4symbols([NAMES...]) | With no arguments, `m4symbols' expands to a unordered, comma-separated | list of the names of all currently defined macro. Each macro name is | quoted. In other m4 implementations (I tested Solaris and OpenBSD), dumpdef output is also unordered - it is only ordered on GNU. But I would be okay with a documented change to dumpdef behavior to be unordered, particularly since we could then do: define(`dumpdef', `builtin(`dumpdef', sort(m4symbols))') to recover the former behavior. | -- Builtin (list): sort(NAME, [...]) | Expands to a sorted, comma-separated list of quoted NAME arguments. | This macro was added in M4 2.0. | At which point, the user can easily create: define(`cmp', `ifelse(`$1', `$2', `0', ~ (sort(`$1', `$2')), `($1,$2)', `-1', ~ `1')') | | -- Builtin (list): uniq(NAME, [...]) | Expands to an unordered, comma-separated list of quoted NAME | arguments, | with only the first occurrence of duplicate consecutive parameters | listed in the expansion. This macro was added in M4 2.0. | | uniq(m4symbols(`ifndef', `ifdef', `define', `define', `ifdef', | `undef')) | =>ifdef,define,ifdef Don't you mean ~ =>ifndef,define,ifdef | -- Builtin (list): filter(PATTERN, LIST, [PATSYNTAX]) | Expands to an unordered, comma-separated list of quoted LIST elements | that match PATTERN, either according to the current RESYNTAX (*note | Changeresyntax::) or PATSYNTAX if passed. | | define(`dquote', ``$@'') | => | sort(filter(`*def*', dquote(m4symbols), `GLOB')) | =>define,defn,dumpdef,ifdef,popdef,pushdef,undefine Hmm. This would be the first builtin that takes a quoted list of elements. Maybe it would be worth also making dquote builtin: - -- Builtin (list): dquote(ELEMENT, ...) ~ Expand to a quoted, comma-separated list of quoted list ELEMENTs. so that you could use dquote regardless of the current quoting characters (in your example, it would only work with `'). Then again, dquote is easy to implement efficiently without needing another builtin, unlike filter (which can be implemented, but requires a foreach loop). | I'm sure we can implement several of the m4sugar style list mangling macros | eventually, hence I've put these new builtins into a separate list module. Sounds like a good idea to me. I'll see if I can get some time to write up such a module. |> So maybe you could argue that we already have |> globbing if you can just translate the pattern correctly). | | I think this proposal has that covered. I like the idea of using 'GLOB' as another regex syntax, although it implies some intelligence in the underlying regex builtins (either we would do glob->regex translation ourselves, or we would have to decide between re_search vs. fnmatch). - -- Don't work too hard, make some time for fun as well! Eric Blake [EMAIL PROTECTED] -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.5 (Cygwin) Comment: Public key at home.comcast.net/~ericblake/eblake.gpg Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org iD8DBQFHucxH84KuGfSFAYARAg/sAJ0Ykcv8P1j71/hCiIiLdd1OSwC0awCfZ+3h XaAVBMxFHZmtL3vku0OUT+s= =qm5A -----END PGP SIGNATURE----- _______________________________________________ M4-discuss mailing list M4-discuss@gnu.org http://lists.gnu.org/mailman/listinfo/m4-discuss
