un-Nifty qr OR ASCII bullet parser

Description:

While searching for a parse of ASCII bulleted lists the other day, I ended up rolling my own:

while( $text =~ /\G\s*($bullet)\s*([^\n]+)((?:\s*$bullet{2,}\s*[^\n]+)+)?/g ){ ...}

And stumbled across what I believed to be a clever use of qr to create $bullet from a separate data structure (which permits us to later determine what style of bullet we had, and map it to something):

%bullets = ('*'=>'foo', '+'=>'bar', '@'=>'qux');

#Original, which as ikegami points out, doesn't quite work
#my $bullet= sprintf(qr/[%s]/, join('', keys %bullets));
#Alternate form, that I was trying to make more scrutable, with added 
+\Q
my $bullet=  qr/[\Q@{[join '', keys %bullets]}\E]/;

Comment on un-Nifty qr OR ASCII bullet parser Download Code

Replies are listed 'Best First'.
Re: Nifty qr OR bullets with butterfly wings by ikegami (Patriarch) on Aug 13, 2009 at 19:24 UTC
Safer (allows "`-`", for example): `my $bullet = sprintf qr/[%s]/, quotemeta join '', keys %bullets;` [download] Alternative (shorter and returns a compiled regexp unlike the OP's and the above solutions): `my ($bullet) = map qr/[\Q$_\E]/, join '', keys %bullets;` [download]	[reply] [d/l] [select]
Re^2: Nifty qr OR bullets with butterfly wings by belg4mit (Prior) on Aug 13, 2009 at 20:00 UTC
Alternative (shorter and returns a compiled regexp unlike the OP's and the above solutions): Huh? My code returns `(?-xism:[@*+])`, but the inclusion of \Q is a good idea. `-- In Bob We Trust, All Others Bring Data.`	[reply] [d/l]
Re^3: Nifty qr OR bullets with butterfly wings by ikegami (Patriarch) on Aug 14, 2009 at 02:59 UTC
It returns the string `(?-xism:[@*+])` `qr/[%s]/` builds a regex that matches strings containing "`%`" or "`s`". `sprintf` stringifies the compiled regex to `(?-xism:[%s])` to use it as the format pattern. The characters are included into the format pattern and the result is returned by `sprintf`. So not only do you not end up with a compiled pattern, you waste time compiling a pattern you never use!	[reply] [d/l] [select]
Re^4: Nifty qr OR bullets with butterfly wings by belg4mit (Prior) on Aug 14, 2009 at 03:37 UTC


Think about Loose Coupling
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