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Re: Make \< and \> match symbol boundaries
From: |
Miles Bader |
Subject: |
Re: Make \< and \> match symbol boundaries |
Date: |
30 Oct 2001 10:18:11 +0900 |
Richard Stallman <address@hidden> writes:
> Here's another idea: generalize the existing regexps \b, \B, etc. to
> support arbitrary classes and syntaxes, not just word syntax. For
> example, to generalize \b we could add the following regexps:
...
> If we take this approach, then \-<s_ and \->s_ would have the desired
> interpretation of matching symbol boundaries.
I don't think this is true -- one of the more annoying things about
syntax tables is the symbol syntax (_) only applies to those characters
that don't have word syntax, so there's no one syntax that captures
both.
So the the suggested \-<s_ would only match the beginning of `_foo', not
`foo'.
This is why I'm a bit leary of any new syntax that only accepts a single
syntax class, as it fails for such a common case.
How about adding the ability to use `syntax sets'? Then the above new
syntax could be made to do the right thing. For instance, anyplace in a
regexp that accepts a syntax class character could be extended to also
support a set of syntax class characters, surrounded by `[' and ']'.
Then one could use \s[w_] to match a word-or-symbol character, and
using Dave's new syntax, \-<s[w_] would be equivalent to \_< .
-Miles
--
I'd rather be consing.
- Re[2]: idea -> internal frames?, (continued)
- Re: idea -> internal frames?, Jason Rumney, 2001/10/26
- Re: idea -> internal frames?, Kevin A. Burton, 2001/10/24
- Re: Make \< and \> match symbol boundaries, Stefan Monnier, 2001/10/28
- Re: Make \< and \> match symbol boundaries, Paul Eggert, 2001/10/28
- Re: Make \< and \> match symbol boundaries, Stefan Monnier, 2001/10/28
- Re: Make \< and \> match symbol boundaries, Miles Bader, 2001/10/29