From: Mikel Lindsaar <raasdnil@...>
Date: 2007-07-20T13:47:45+09:00
Subject: Re: regex backreference weirdness...

Instead of reinventing the wheel, you could always use the camelcase
converter that Rails has and pull out what you need:

http://api.rubyonrails.com/classes/ActiveSupport/CoreExtensions/String/Inflections.html

Regards

Mikel

On 7/20/07, Kyle Schmitt <kyleaschmitt@gmail.com> wrote:
> It all started with trying to convert some strings with underscores in
> them, to camel case...and me thinking of regexes as sed regexes
>
> It looks like gsub saves back references, but only after the whole
> method exits, so it can't use what it found.  Is this right?
>
> Below is what I tried, which leads me up to the question of... what
> would the _right_ way be of doing this?
>
> irb>"camel_case".gsub(/_(.)/,$1.upcase)
> NoMethodError: undefined method `upcase' for nil:NilClass
>         from (irb):1
> #Which made me say Hu?  it looks like a valid back reference to me...
> #So I tried
> "camel_case"=~/_(.)/
> irb>puts $1
> =>"c"
> #ok really wierd...
> irb>"camel_case".gsub(/_(.)/,$1.upcase)
> =>"camelCase"
> #Right, I'll buy that since $1 is still hanging around
> irb>"camel_face".gsub(/_(.)/,$1.upcase)
> =>"camelCase"
> irb>"camel_face".gsub(/_(.)/,$1.upcase)
> =>"camelFase"
> #Ha ha!  gsub DOES save a backreference... so why isn't this working?! :(
>
>