Re: [gobo-eiffel-develop] Cannot reuse RX_PCRE_REGULAR_EXPRESSION instance

[Eric B. <er...@go...>]

"Jason Wei [ES]" <ja...@ei...> wrote:
> I created an RX_PCRE_REGULAR_EXPRESSION object for regular expression 
> matching.
> And I have setup options I need.
> 
> I used it to do a first match using keyword *"a*"*, I got the right result.
> I used it to do a second match using keyword *"^a*"*, I got the right 
> result again. (Of course, I called `compile (keyword)' everytime).
> Now I used it to do a third match using the keyword *"a*"* again over 
> the same context, then I got different result from the first match.
> 
> During these three tries, I don't change any options, so I think I don't 
> need to call `reset'. But even if I called `reset' every time, I got 
> different results.
> 
> And I provided a small application to show this problem. Just run this 
> application which check enabled and observe the assertion violation.
> 
> It there anything else that I need to do to make it work?

There are two ways to tell the regexp to match from the
start: either put the character '^' at the beginning of
the regexp:

    regexp.compile ("^a*")

or set the option `is_anchored':

    regexp.set_anchored (True)
    regexp.compile ("a*")

In both cases `is_anchored' is set to True. If later on
you want the regexp to match anywhere in the string, you
have to unset `is_anchored':

    regexp.set_anchored (False)
    regexp.compile ("a*")

So, in your example:

    l_filter := filter_engine
    l_filter.set_anchored (False)
    l_filter.reset
    l_filter.compile (a_keyword)

-- 
Eric Bezault
mailto:er...@go...
http://www.gobosoft.com