From: Gianfranco Bozzetti <gf.bozzetti@...>
Date: 2010-08-20T00:26:54+09:00
Subject: Re: ambiguous first argument?

Roger Pack wrote:
> Hi all.
> With this code:
> 
> memory_bitmap.scan /\x00{5}+/
> 
> I get this warning:
> 
> test.rb:1: warning: ambiguous first argument; put parentheses or even
> spaces
> 
> Could somebody please help me to understand what exactly is ambiguous
> there?
> Thank you!
> -r

The ambiguity comes from the double quantifier {5}+ where:
- {5} means exactly 5 occurrences of \x00
- +   means 1 or more occurrences of preceding expression.

Given the string:
bitmap="\x30\x50\-\x00\x00\x00\x00\x00\x00\-\x40\x50\x30"

p bitmap.scan(/\x00+/)       #=> ["\000\000\000\000\000\000"]
p bitmap.scan(/\x00{2}/)     #=> ["\000\000", "\000\000", "\000\000"]

HTH gfb
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