From: Glenn Jackman <glennj@...>
Date: 2009-07-15T03:40:07+09:00
Subject: Re: a regex that does not contain comma

At 2009-07-14 08:54AM, "David A. Black" wrote:
>  Hi --
>  
>  On Tue, 14 Jul 2009, Glenn Jackman wrote:
>  
> >    case string
> >    when /,/       then puts "#{string.inspect} contains a comma"
> >    when /^[^,]*$/ then puts "#{string.inspect} has no comma"
> >    end
>  
>  That second regex, on its own, won't tell you the whole story:
>  
>     string = <<-EOM
>     Hi.
>     I have, at a minimum, two commas.
>     Bye.
>     EOM
>  
>     p "Match!" if /^[^,]*$/.match(string)
>       => Match!
>  
>  You'd want to use \A and \z, rather than ^ and $ (which delimit lines,
>  rather than the whole string).
>  
>  But if you've already tested for /,/, then you should be able just to
>  have an else clause in your case statement, to cover cases where /,/
>  didn't match.

Yes, I could have used the else clause, but I wanted to explicitly spell
out the "negation" of /,/ in case the OP required it.  

Coming from Tcl and Perl, and being used to line-wise parsing, I wasn't
fully aware of the difference between ^$ and \A\Z

Thanks for learnin' me.

-- 
Glenn Jackman
    Write a wise saying and your name will live forever. -- Anonymous