From: Jason Persampieri <jason@...>
Date: 2002-12-20T16:48:49+09:00
Subject: Re: Few question about IO

> does not work for me:
> irb(main):032:0> ": dbl dup +
> ;".gsub(%r[(\s|^)\+(\s|$)], %Q[\1:plus:\2])
> => ": dbl dup\001:plus:\002;"
> 
> something is wrong with \1 and \2
> 

%Q is equivalent to double-quoting.
%q is equivalent to single-quoting

irb(main):002:0> "\1"
"\001"
irb(main):003:0> '\1'
"\\1"
irb(main):004:0> %Q(\1)
"\001"
irb(main):005:0> %q(\1)
"\\1"

When you call gsub, you must use the single-quoted
form.  This 'gotcha' just bit me earlier today.

Jason

PS.  It feels really good to be able to actually help
others for a change.  ;)