Re: Multi-Line Definitions

[Eric Blake]

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According to Eric Blake on 9/29/2007 1:31 PM:
> Here's something a bit more telling.  With the attached patch, and in the
> coreutils directory,
> 
> $ M4_TRACE_FILE=~/m4.trace M4=~/m4/src/m4 autoconf
> $ wc m4.trace
>  62207  61314 666720 m4.trace
> $ sort -u m4.trace | wc
>     401     405    5619
> $ sort <m4.trace | uniq -c |sort -n -k1,1 |tail -n 15
>     740 [\\'']
>     816 (.*)
>     863
> ^[abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ_][abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ_0123456789]*$
>    1163  \(..\)$
>    1163 \\
>    1163 ^\(..\)
>    2244 [^a-zA-Z0-9_]
>    2324 [      ]+
>    3242
>    4306 \\[`""]
>    5020 [`""]
>    5020 \\[\\$]
>    7376 [`$]
>   11504 @\(<:\|:>\|S|\|%:\)@
>   11915 @&t@

After this week's autoconf patches, the regex count when running autoconf
on coreutils is now:

$ wc m4.trace
 7759 12439 90000 m4.trace
$ sort -u m4.trace|wc
     34      43     650
$ sort m4.trace | uniq -c |sort -n -k1,1 |tail -n20
     25 r:n:{[:;]}
     36 p:y:{:}
     36 r:n:{:}
     38 p:y:{:.*\(.\)$}
     39 p:y:{[\"$`]}
     41 r:n:{\.}
     50 p:y:{\([0-9]+\)\([abcdefghi]\)}
     50 p:y:{\([0-9]+\)\([jklmnopqrs]\)}
     50 p:y:{\([0-9]+\)\([tuvwxyz]\)}
     98 p:y:{.}
    122 p:n:{\..*}
    122 p:n:{^[^.]*\.}
    127 p:y:{[`""]}
    287 p:y:{[\\`]}
    364 p:n:{(.*)}
    397 p:y:{[\\'']}
   1163 p:n:{\\
   1163 p:y:{^. ?\(.*\) .$}
   1164 }
   2324 p:y:{[   ]+}

Of the above list, the first line which doesn't represent multi-character
replacement or true regex pattern searching is
      98 p:y:{.}
(from m4_text_box); the returns for fixing this, or any other
low-frequency pattern, to avoid regexes is probably too small to be worth
the effort.  I don't see any more obvious speed improvements on the
autoconf side of things (although the m4 side of things can probably be
improved; just hanging on to the last 4 most recently compiled regex
should probably speed things up).

For my next autoconf-patches thread, I'll optimize autom4te
- --language=autotest :)

- --
Don't work too hard, make some time for fun as well!

Eric Blake             address@hidden
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