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Re: string-match bug?
From: |
David Kastrup |
Subject: |
Re: string-match bug? |
Date: |
Mon, 14 Dec 2009 14:51:20 +0100 |
User-agent: |
Gnus/5.13 (Gnus v5.13) Emacs/23.1.50 (gnu/linux) |
Andreas Röhler <andreas.roehler@easy-emacs.de> writes:
> Barry Margolin wrote:
>> In article <mailman.12469.1260221021.2239.help-gnu-emacs@gnu.org>,
>> Matthew Dempsky <matthew@dempsky.org> wrote:
>>
>>> On Mon, Dec 7, 2009 at 12:37 PM, Andreas Röhler
>>> <andreas.roehler@easy-emacs.de> wrote:
>>>> Why should questioned string respond here it contains an empty string at
>>>> position 0?
>>>> Makes no sense for me.
>>> Here's an analogy: (string-match "xyzzy" "fooxyzzybar") returns 3.
>>> This is because the first 5 characters starting at position 3 are
>>> "xyzzy", the same as the first string parameter. The significance of
>>> 5 here is the length of "xyzzy".
>>>
>>> Similarly, (string-match "" "foo") returns 0. This is because the
>>> first 0 characters starting at position are "", the same as the first
>>> string parameter.
>>
>> Here's another example of a limit case:
>>
>> (string-match "a*" "b") returns 0, because a* matches zero or more a's,
>> and there are zero a's at position 0.
>
> Hmm, interesting
>
> IMHO that differs:
>
> Still pretending: the empty string can't match any non-empty string,
> at no position...
Since (concat "" "foo")->"foo", obviously "" is contained in "foo" at
position 0. The same argument holds for any other position. Including
after the last character.
--
David Kastrup
- Re: string-match bug?, (continued)
- Message not available
- Re: string-match bug?, David Kastrup, 2009/12/14
- Message not available
- Re: string-match bug?, Stefan Monnier, 2009/12/09
- Re: string-match bug?, Andreas Röhler, 2009/12/10
- Message not available
- Re: string-match bug?, Frank Fredstone, 2009/12/10
- Re: string-match bug?, Andreas Röhler, 2009/12/10
- Re: string-match bug?, Juanma Barranquero, 2009/12/10
- Message not available
- Re: string-match bug?, Frank Fredstone, 2009/12/10
- Message not available
- Re: string-match bug?,
David Kastrup <=