Hi Eric, * Eric Blake wrote on Thu, Nov 20, 2008 at 02:39:56PM CET: > According to Ralf Wildenhues on 11/19/2008 11:01 PM: > >> +creative shell comments to supply the balance. Note that you should use > >> +the quadrigraph @samp{@@%:@@} and not a literal @samp{#}, because the > >> +latter hides the @samp{(} inside an m4 comment, and you would still be > >> +presenting m4 with unbalanced parentheses. > > > > But not the human reader of the macro text! IIUC then as the code > > is capable, we *can* use `in #(', which is much more readable than > > `in @:@('. I've never knowingly added the extra opening parenthesis > > in order to help M4, only ever in order to help paren matching > > algorithms in $EDITORs. > > Hmm. Yet it was your message in > http://lists.gnu.org/archive/html/autoconf-patches/2006-05/msg00168.html > that caused Paul to have to do just that in commit e07dd (note that he had > to replace 'case "$ac_try" in #((' with 'case "(($ac_try" in').
Oohh. I forgot. :-) Yes, that was one of the last-minute changes for compatibility issues that showed up during release testing. Ugly kinds of things. Disadvantage of git: makes you confess old sins. ;-) > Just because m4_expand can handle #( doesn't mean that other macros can; > you still have a bug if you do: [...] Yep. > So, I will reword this paragraph to mention all of the possibilities, each > with their strengths and drawbacks. Thanks. > > And no, I don't really understand. > > Here's a single-stepped example. The first argument to _m4_expand is > always the original argument, the second is the number of open '(' to add > if an unbalance is detected, What if there are already too many '('? Will it loop endlessly and fill RAM with more '('? [...] > Slick, huh? Yes. Quite unobvious. > > I do wonder when quadrigraphs for `(' and `)' will finally be added, > > though. > > Already done :(. In 2.63. Oh. Cheers, and sorry for not adding any useful content, Ralf PS: ah, wait: if you would change Subject:s with '(was: $old_subject)', i.e., using conforming parentheses instead of brackets, my mailer would be able to cut off the old subject automagically. There, some useful content. :-)