Suggestion to let m4 discard comments

[Daniel Goldman]

I'd like to suggest to let m4 discard comments in a future version. By 
comment, of course I mean everything between # and newline, or the 
comment delimiters set by m4_changecom macro.

My suggestion is to add a command line option so m4 discards comments, 
neither processes nor outputs anything in the comment. Just about any 
language allows this capability, for very obvious reasons. Any reason 
not to let m4 discard comments?

Alternatively, m4 behavior could be changed to always discard the 
comment. I can't imagine wanting to send commented text to the output, 
so the current behavior seems weird to me. I'm interested to learn the 
rationale. What might be the usefulness of sending commented text to the 
output? Anyway, a command line option seems good enough.

I tried m4_divert(-1) as a work-around. Although it discards the output, 
it still processes the commands, so it fails to provide the needed 
functionality. At least half the time when I need to comment a section, 
m4_divert(-1) fails because it still processes the text, causing an 
error. And m4_divert(-1) seems obviously a kludge as a comment mechanism.

I also use m4_dnl as a work-around. But this only works a line at a 
time, blends in with the surrounding text, again seems a kludge, and 
looks really geeky (not at all like standard easily recognizable comment 
symbols).

I think m4 would be better (more useful) if it allowed comments that 
work the same way as other commonly used languages (C, Java, etc). It 
seems odd this was not put in long ago.

http://www.seindal.dk/rene/gnu/visions.htm was found on a search. It 
suggests this change was desired many years ago, and was even added as 
--discard-comments at one point (and I guess removed for some reason).

I have no idea how difficult (or easy) the change would be, but to me it 
seems pretty useful.

Thanks,
Daniel