From: Ravil Bayramgalin <ravwar@...>
Date: 2008-03-22T02:41:34+09:00
Subject: Re: A question involving variable evaluation

just store a needed match position for every pattern and then use it like that:

string = 'foobar'
patterns = [[/(oo)+(.*)/, 2], [/(.*)bar/, 1]]
p patterns.map {|regexp, position| string[regexp, position] }

2008/3/21, mike leonard <mikeleonard@gmail.com>:
> On Mar 21, 7:57 am, mike leonard <mikeleon...@gmail.com> wrote:
>  > Hello friends,
>  >
>  > I'm working on some code that will iterate through an array of regex
>  > patterns and values, returning a value when the corresponding regex is
>  > matched:
>  >
>  > the_string = "foobar"
>  > patterns_and_values = [[/(foo)(.*)/, "bar"], [/(bar)/, "foo"]]
>  > patterns_and_values.each do |p|
>  >     the_match = the_string.match(p[0])
>  >     if the_match then
>  >         return p[1]
>  >     end
>  > end
>  >
>  > To make this more useful, I'd like to be able to use the subexpression
>  > globals in the value that is returned, like so:
>  >
>  > patterns = [[/(foo)(.*)/, $~[0]], [/(bar)/, $~[1]]
>  >
>  > However, what is actually returned is the value of $~[0] at the time
>  > that the patterns array was created, which is nil. Is there a good way
>  > to achieve this without resorting to eval? I'd like to keep the syntax
>  > of the patterns_and_values array as simple as possible, since this
>  > will be exposed to users so that they can add to it as necessary.
>  >
>  > Thank you kindly in advance (and apologies if the above syntax isn't
>  > quite right - I don't have Ruby installed on this machine).
>  >
>  > --Mike Leonard
>
>
> To simplify this somewhat convoluted question:
>
>  After I assign the pattern matching globals ($~[0] et al) to a
>  variable, is there a way to re-evaluate this variable after a match
>  has occurred, so as to keep it consistent with the actual current
>  value of $~[0], as opposed to what the value was when the variable was
>  created?
>
>  Many thanks,
>
>
>  Mike Leonard
>
>


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