From: CarlosRivera <CarlosRivera@...>
Date: 2004-09-20T16:54:39+09:00
Subject: regular expression seems broken not greedy when it should be


I am very new to ruby.  I was working my way through the tutorials. 
However, it looks like the regular expressions seem broken; however, 
since I am so new to ruby it could be me.  It would appear that the 
regular expressions are not greedy.

I have the following code:

def showRE(a,re)

	startMarker = "<<<"
	endMarker = ">>>"

	if a =~ re
		"#{$`}#{startMarker}#{$&}#{endMarker}#{$'}"
	else
		"no match for '#{a}'"
	end
end


irb(main):012:0> showRE("abc123def", /\d*/)
=> "<<<>>>abc123def"
irb(main):013:0> showRE("abc123def", /\d+/)
=> "abc<<<123>>>def"
irb(main):014:0>

I thought that normally * was greedy and would try to match the largest 
string and not the tiniest.  If this is the case the "<<<" and ">>>" 
should be around the number "123" in the output for the first attempt 
similar to the second function call.  In the ruby docs, it states at the 
following URL:

http://www.ruby-doc.org/docs/ProgrammingRuby/html/language.html#UL

The following:

	re  ?

	Matches zero or one occurrence of re. The *, +, and {m,n} modifiers are 
greedy by default. Append a question mark to make them minimal.

Did I misinterpret something?  My ruby information:

ruby 1.8.1 (2003-12-25) [i386-openbsd3.5]