--- On Wed, 11/3/10, John Bond <li...@asd-group.com> wrote:
> 3) then said there must be >=0 occurrences of what's inside it,
> which of course there is, so that has no effect.
>
> ((.a.)*)*
Hi,
I think there should be a difference: unlike before,
now what's inside the outer group can match an empty
string. And so by reason of the greediness of the
quantifier * of the outer group (that is, the last *),
it should take up the empty string after each
non-empty match.
So, the first match in 'Mary has a lamb' must be:
'' + 'Mar' + '' (the empty string before the 'y')
(note the first '' is before the 'M')
Then, after skipping the 'y' (remember, the empty
string before 'y' is already taken), comes a second:
'' (the one between 'y' and ' ')
Then after skipping the space ' ', comes a third:
'has' + ' a ' + 'lam' + '' (the empty string before the 'b')
And finally, it matches the empty string after 'b':
''
So there should be total of four matches -- isn't it?
Yingjie
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