Re: FYI: Regex paper for UTC

   Philippe Verdy wrote:

> [...] For me, a regexp is not a string, but [...]

   No, no, no. A "regular expression", by definition, denotes a "regular set".
This is just basic theoretical comp sci.  Some regular sets are finite (and in
fact any finite set is a regular set). Other regular sets are infinite, which
means they are not tractable per se on a computer. Which is why we represent
them as regular expressions.

   For instance, the regular expression /a*/ denotes the (infinite) regular set
{"", "a", "aa", "aaa", ...}.

   All you need to do to define a regular expression is to define what members
its regular set has. That's all.

   The question of "matching" is then just a question of set membership. "aa"
matches the regexp /a*/ because "aa" is in the regular set denoted by /a*/. You
can ask & answer other questions, like, "What is the longest match?", "What
elements contain "aa" as a substring?", etc, but let's keep the terminology
straight. It's not really up for grabs at this point.
-- 
... Jonathan Coxhead

   "People assume that time is a strict progression of cause to effect, but
actually from a non-linear, non-subjective viewpoint, it's more like a big ball
of wibbly-wobbly, timey-wimey ... stuff." ---The Doctor