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.

-- 
Barry Margolin, barmar@alum.mit.edu
Arlington, MA
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