From: Xiong Chiamiov <xiong.chiamiov+ruby_forum@...>
Date: 2008-09-10T07:45:08+09:00
Subject: problems with oniguruma lookahead

Ruby 1.8.6 with Oniguruama installed and working (everywhere else, this
seems to be my problem).

Let me preface this by saying that I am new to Ruby (and kinda jumped
in, rather than learning it properly), and regexes are not my thing -
that why I have nifty regex-checkers.

I am trying to extract some parts out of a string
("<p><b>'Algebra'</b><br>") that I scraped from some html.  I'm getting
nil returned from the expression:

Oniguruma::ORegexp.new("(?<=<p><b>').*(?='</b><br>)").scan(scraped_html)

with scraped_html being the string mentioned above.

Doing some experimenting, I have found that the first part works just as
planned (eg, everything except the lookahead).  Using wildcards (. and
*) works as well:

Oniguruma::ORegexp.new("(?<=<p><b>').*(?=.)").scan(scraped_html)

returns [#<MatchData "Foo'</b><br">, #<MatchData "Bar'</b><br">], as
expected.  However, anything else (<, b, \w, etc.) causes the regex to
not match.

I am quite befuddled about this, though I (almost certainly) know it is
my fault.  Any help would be much appreciated.

Also, if I am violating any mailing-list netiquette, I would like to
know as well.
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