From: 7stud -- <bbxx789_05ss@...>
Date: 2011-05-03T03:09:30+09:00
Subject: Re: Formatting a long regex: can a character class [] be split over lines?

Alexey Muranov wrote in post #996071:
> Hello,
> i am wandering if it is possible to split a character class ([...]) in
> Ruby regex over multiple lines.
>
> I know that the /x option allows to ignore whitespace, so i can write :
>
>     email_format = /\A(
>                       [A-Za-z\d\!\#\$\%\&\'\*\+\-\/\=\?\^\_\`\{\|\}\~]+
>                       \.)*
>                       [A-Za-z\d\!\#\$\%\&\'\*\+\-\/\=\?\^\_\`\{\|\}\~]+
>                       @([a-z\d\-]+\.)+[a-z\d\-]+\z/x
>
> However, if i try to split inside a character class:
>
>     name_format = /\A[A-Za-z\d
>                       \!\#\$\%\&\'\*\+\-\/\=\?\^\_\`\{\|\}\~]\z/x
>
> i get the warning:
>
>     warning: character class has duplicated range
>
> (apparently it is about the space character being included multiple
> times inside []).
> I want the space and newlines to be disregarded inside [] to format it
> over multiple lines, is this possible?
>
> Thanks,
>
> Alexey.


1) Never write a regex with thousands of escapes.  Are you aware that 
inside a character class, the special regex characters lose their 
special meaning?

2) Break up long regexes into smaller pieces.


my_char_class = '[A-Za-z#\d!#$%&\'*+-/=?^_`{|}~]'

my_regex = /
              \A
              #{my_char_class}
              [.]
              #{my_char_class}
              \z
           /x


if my_regex.match "?./"
  puts 'yes'
end

--output:--
yes

-- 
Posted via http://www.ruby-forum.com/.