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Re: string-match bug?


From: Juanma Barranquero
Subject: Re: string-match bug?
Date: Tue, 8 Dec 2009 12:35:34 +0100

On Tue, Dec 8, 2009 at 11:42, Andreas Röhler
<andreas.roehler@easy-emacs.de> wrote:

> Well, string-match should tell first point of occurrence if any.

This is exactly what it does.

> If we have none, as with slightly changed example
>
> (string-match "xyzzy" "foox-a-yzzybar")
> it duly returns "nil"  - and not "0" saying falsly "first point of 
> non-occurence"

It returns nil, i.e.: there's no point in the target string at which
the regexp matches.

> (string-match "" "fooxyzzybar") asks, if there is an empty string in string.
> If yes, report the starting point of the empty string.
>
> Does string start with an empty string? IMHO not.

It returns 0, i.e.: this is the point at which the target string
matches ("" will match at the beginning of every string).

It's entirely consistent. You want string-match to answer different
questions in your first and second examples.

    Juanma




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