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Re: How are regexen implemented in Emacs?
From: |
Stefan Monnier |
Subject: |
Re: How are regexen implemented in Emacs? |
Date: |
Tue, 13 Dec 2022 11:16:12 -0500 |
User-agent: |
Gnus/5.13 (Gnus v5.13) |
> Perl does the latter. That has saved my bacon from time to time.
> So that seems possible with a backtracker, too. Don't ask me how,
> though :-)
Indeed, it's not more difficulty to allow to run ELisp/Perl
code in the middle of the backtracking match than a non-backtracking
one, but the difference is in the number of times the ELisp/Perl code
may need to be run, which changes the performance profile (and hence
the potential use-cases) significantly.
Stefan
PS: Regarding non-backtracking matchers are backreferences, most of the
uses of backreferences I'm familiar with *can* be implemented without
backtracking because the subgroup to which the backref points has only
one possible way to match. It won't handle cases like
`diff-merge-strings`, but it's still an important subset of cases.
- How are regexen implemented in Emacs?, Marcin Borkowski, 2022/12/12
- Re: How are regexen implemented in Emacs?, Stefan Monnier, 2022/12/12
- Re: How are regexen implemented in Emacs?, Marcin Borkowski, 2022/12/12
- Re: How are regexen implemented in Emacs?, Stefan Monnier, 2022/12/12
- Re: How are regexen implemented in Emacs?, Marcin Borkowski, 2022/12/12
- Re: How are regexen implemented in Emacs?, Stefan Monnier, 2022/12/12
- Re: How are regexen implemented in Emacs?, tomas, 2022/12/13
- Re: How are regexen implemented in Emacs?,
Stefan Monnier <=
- Re: How are regexen implemented in Emacs?, Emanuel Berg, 2022/12/15
- Re: How are regexen implemented in Emacs?, Akib Azmain Turja, 2022/12/16
- Re: How are regexen implemented in Emacs?, Emanuel Berg, 2022/12/17
- Re: How are regexen implemented in Emacs?, Jean Louis, 2022/12/18
- Re: How are regexen implemented in Emacs?, Emanuel Berg, 2022/12/20
- Re: How are regexen implemented in Emacs?, tomas, 2022/12/12
- Re: How are regexen implemented in Emacs?, Marcin Borkowski, 2022/12/12
- Re: How are regexen implemented in Emacs?, Stefan Monnier, 2022/12/12
- Re: How are regexen implemented in Emacs?, Emanuel Berg, 2022/12/15
- Re: How are regexen implemented in Emacs?, tomas, 2022/12/15