From: "David A. Black" <dblack@...>
Date: 2007-08-23T04:05:43+09:00
Subject: Re: de-camelcase a filename

Hi --

On Thu, 23 Aug 2007, Robert Dober wrote:

> On 8/22/07, Daniel Berger <djberg96@gmail.com> wrote:
>> On Jul 2, 11:42 am, Ezra Zygmuntowicz <ezmob...@gmail.com> wrote:
>>> On Jul 2, 2007, at 9:41 AM, Bill Kelly wrote:
>>>
>>>> From: "Roseanne Zhang" <rosea...@javaranch.com>
>>>>> How about this:
>>>>> "FooBarBaz".split(/(?=[A-Z])/).join('_').downcase
>>>
>>>> Nice... (why didn't I think of that :)
>>>
>>> This is the cleanest I've come up with:
>>>
>>> class String
>>>    # "FooBar".snake_case #=> "foo_bar"
>>>    def snake_case
>>>      gsub(/\B[A-Z]/, '_\&').downcase
>>>    end
>>> end
>>
>> Both of these solutions have a problem with back to back caps. For
>> example:
>>
>> "CheckHostIP".gsub(/\B[A-Z]/, '_\&').downcase => "check_host_i_p"
>>
>> But I want "check_host_ip". It's probably a simple tweak, but I'm
>> having trouble finding it at the moment. Suggestions?
>>
>> Thanks,
>>
>> Dan
>
> I guess there can be no general solution, I would like
> HostIP --> host_ip
> but
> AHostIP --> a_host_ip

Here's how ActiveSupport does it:

   def underscore(camel_cased_word)
     camel_cased_word.to_s.gsub(/::/, '/').
       gsub(/([A-Z]+)([A-Z][a-z])/,'\1_\2').
       gsub(/([a-z\d])([A-Z])/,'\1_\2').
       tr("-", "_").
       downcase
   end


David

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