Re: regex help wanted

On 25 April 2013 15:32, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:
> Karsten Hilbert <Karsten(dot)Hilbert(at)gmx(dot)net> writes:
>> What I don't understand is: Why does the following return a
>> substring ?
>
>> select substring ('junk $<allergy::test::99>$ junk' from '\$<[^<]+?::[^:]+?>\$');
>
> There's a perfectly valid match in which [^<]+? matches allergy::test
> and [^:]+? matches 99.

Yeah, I think there may be an assumption that a lazy quantifier will
stop short and cause the remainder to fail to match permanently, but
it will backtrack, forcing the lazy quantifier to expand until it can
match the expression.

--
Thom