From: Calvin Bornhofen <calvin.bornhofen@...>
Date: 2013-04-19T03:14:42+09:00
Subject: Re: Match against multiple patterns problem

Hello,

there are two possible solutions coming to my mind:
- Using the global $~, the last matched expression (equivalent to the 
return value of Regexp.last_match). This is not as good as the second 
idea imo, because you just get rid of the assignment, but your code is 
still as wet.
- Since the pattern is "if match then return [something_changing, 
m[0]]", you could put all your regular expressions as well as the 
changing part in a hash and then loop through it.

I think the second approach is better, since you avoid a lot of code 
duplication and it gets more maintainable (because you just have to 
modify the hash if you want to add/remove/modify one or more of your 
patterns and changing strings).

It would look something like this:

hsh = { /^[^\W_]+/ => "1", /^\s+/ )> "a" }
s = s.to_s
return ["1", ""] unless s.size >= 1
hsh.each do |regex, text|
   if regex =~ s
     return [text, Regexp.last_match 0]
   end
end

Hope this helps.

Regards,
Calvin

On 18.04.2013 19:40, Charles Hixson wrote:
> What I would want to do, if it were legal code would be:
>         if    not s.is_a?(String)    or    len(s) < 1 then    
> return    ["1",""]
>         if    (m = /^[^\W_]+/.match(s) ) !== nil    then return    
> ["a", m[0]]
>         elsif    (m = /^\s+/.match(s) ) != nil      then return    
> ["s", m[0]]
>         elsif    (m = /^[[:cntrl:]]+/) != nil       then return    
> ["c", m[0]]
>         elsif    (m = /^[[:punct:]_]+/) != nil      then return    
> ["p", m[0]]
>         elsif    (m = /^[^\w\s[:cntrl:][:punct:]]+/) != nil
>                                                     then return    
> ["r", m[0]]
> But this isn't legal, because one can't do an assignment within a 
> logic test (any expression?).
> So what SHOULD I do?  I can double the length of the code by pulling 
> the assignments out, and
> interleaving tests and assignments, but that's ugly (i.e., it makes 
> the code harder to read).  Any better choices?
>