From: Francis Hwang <sera@...>
Date: 2004-11-18T13:36:25+09:00
Subject: Re: Regexp bug in 1.9.0?


On Nov 17, 2004, at 10:55 PM, James Edward Gray II wrote:

> On Nov 17, 2004, at 9:47 PM, Francis Hwang wrote:
>
>> Is this behavior a bug, or am I misunderstanding how I should make a 
>> regexp?
>>
>> irb(main):001:0> str = "123.456.*"
>> => "123.456.*"
>> irb(main):002:0> str =~ /^[0123456789.-*]+/
>> SyntaxError: compile error
>> (irb):2: empty range in char class: /^[0123456789.-*]+/
>>         from (irb):2
>> irb(main):003:0> str =~ /^[0123456789*.-]+/
>> => 0
>
> - is a special character inside a Regexp character class.  It means, 
> from this (character left of dash) to this (character right of dash).  
> It's usually used to say A-Z, a-z, 0-9, or similar.  Putting it at the 
> beginning or end of a class negates this special meaning, thus the 
> change in the second attempt.

Ah, of course. I fixated on the * and totally forgot about what the - 
was doing. Thanks.

F.