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Re: For text processing, which is more powerful, emacs or perl?
From: |
tomas |
Subject: |
Re: For text processing, which is more powerful, emacs or perl? |
Date: |
Sun, 20 Dec 2020 10:01:18 +0100 |
User-agent: |
Mutt/1.5.21 (2010-09-15) |
On Sat, Dec 19, 2020 at 11:01:52AM -0500, Stefan Monnier wrote:
> > It's well known that perl's regexp is very powerful for its capability
> > of text processing. So, which is more powerful, emacs or perl, in this
> > scenario?
>
> Probably Snobol or Icon.
Tcl ;-P
While somewhat tongue-in-cheek, I have some (by now older) reference to
back it [1]. The gist is that Tcl actually implements Thompson's clever
strategy (NFA -> power set DFA, yadda, yadda), while the P* languages
(Perl, Python, PHP, Ruby... to me, they are quite similar, all of them
[2]) all seem to use backtracking implementations. They do have a more
convenient (and strictly more powerful!) RE language, but they do pay
the price in terms of the occassional exponential runaway [3].
Now to the tongue-in-cheek part: Tcl has evolved since [1] (which was
around 2007) -- as have the other P*s. Among other things, I hear that
they have overhauled their regexpery (which is something awe-inspiring:
most projects, once they have a regexp engine in them, DON'T TOUCH IT.
Too much black magic and forgotten lore in there :-) But Tcl folks are
like that.
Perhaps Tcl cas chosen the "convenience" path, and their regexp engine
resembles more that of the P*s these days.
Cheers
[1] "Regular Expression Matching Can Be Simple And Fast
(but is slow in Java, Perl, PHP, Python, Ruby, ...)"
<https://swtch.com/~rsc/regexp/regexp1.html>
[2] But I do enjoy (a limited amount) of those bragging contests
"My Python is better than your Perl, nyah, nyah". They tickle
the hobby anthropoligist in me ;-)
[3] This afforded me a job asignment a long, long time ago
- t
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- Re: For text processing, which is more powerful, emacs or perl?, (continued)
- Re: For text processing, which is more powerful, emacs or perl?, Harald Jörg, 2020/12/19
- Re: For text processing, which is more powerful, emacs or perl?, Jean Louis, 2020/12/19
Re: For text processing, which is more powerful, emacs or perl?, Stefan Monnier, 2020/12/19
- Re: For text processing, which is more powerful, emacs or perl?, Jean Louis, 2020/12/20
- Re: For text processing, which is more powerful, emacs or perl?, Stefan Monnier, 2020/12/20
- Re: For text processing, which is more powerful, emacs or perl?, tomas, 2020/12/20
Re: For text processing, which is more powerful, emacs or perl?,
tomas <=