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Re: find-file-noselect needs save-match-data
From: |
Herbert Euler |
Subject: |
Re: find-file-noselect needs save-match-data |
Date: |
Sat, 16 Jun 2007 11:50:56 +0800 |
I fail to see the simplicity. All the difficulty comes from having to
think
about when to be careful about the match-data.
What we currently have is a model that each call to the matching
functions such as `string-match', `looking-at' etc changes the
match-data. Furthermore, almost any function calls one of these
functions. So with this model thinking about preserving match-data is
extravagant, since after each call to almost any function, the
match-data is possibly changed. This means that you can't expect the
match-data is preserved even if there is only one simple invocation to
some function between the positions where the matching functions are
called and where the match-data is used, unless the invocation is
inside a `save-match-data' form.
If, for example, we add some function such as `fast-string-match', or
add some variable such as `inhibit-match-data', this actually doesn't
help solve the problem. Since changing match-data is possible by
calling matching functions (although achieving it is a bit difficult
compared with the usage now), match-data is not guaranteed not to be
changed, just as before.
So with the current model, the only way to preserve match-data is to
use the `save-match-data' form everywhere, which is impratical.
But we can't make match-data unchanged, so there seems no solution to
this problem, and just as Stefan said, this is a non-problem.
Regards,
Guanpeng Xu
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- Re: find-file-noselect needs save-match-data, (continued)
- Re: find-file-noselect needs save-match-data, David Kastrup, 2007/06/15
- Re: find-file-noselect needs save-match-data, Richard Stallman, 2007/06/16
- Re: find-file-noselect needs save-match-data, David Kastrup, 2007/06/16
- Re: find-file-noselect needs save-match-data, Richard Stallman, 2007/06/17
- Re: find-file-noselect needs save-match-data, David Kastrup, 2007/06/18
- Re: find-file-noselect needs save-match-data, Richard Stallman, 2007/06/18
- Re: find-file-noselect needs save-match-data, David Kastrup, 2007/06/18
- Re: find-file-noselect needs save-match-data, Richard Stallman, 2007/06/19
- Re: find-file-noselect needs save-match-data, David Kastrup, 2007/06/19
- Re: find-file-noselect needs save-match-data, Richard Stallman, 2007/06/25
- Re: find-file-noselect needs save-match-data,
Herbert Euler <=
- Re: find-file-noselect needs save-match-data, Stefan Monnier, 2007/06/17
- Re: find-file-noselect needs save-match-data, Richard Stallman, 2007/06/16
- Re: find-file-noselect needs save-match-data, Miles Bader, 2007/06/16
- Re: find-file-noselect needs save-match-data, Richard Stallman, 2007/06/17
- Re: find-file-noselect needs save-match-data, Herbert Euler, 2007/06/16
- Re: find-file-noselect needs save-match-data, Herbert Euler, 2007/06/16
- Re: find-file-noselect needs save-match-data, Richard Stallman, 2007/06/17
- Re: find-file-noselect needs save-match-data, Stefan Monnier, 2007/06/17
- Re: find-file-noselect needs save-match-data, Richard Stallman, 2007/06/18
- Re: find-file-noselect needs save-match-data, Herbert Euler, 2007/06/20