From: Robert Klemme <bob.news@...>
Date: 2005-07-14T00:50:51+09:00
Subject: Re: NoMethodError in Range#include?

Levin Alexander wrote:
> Luke Worth <luke@worth.id.au> wrote:
>
>>>    $ ruby -e "puts(('a'..'z').include?(1))"
>>>    -e:1:in `include?': undefined method `>' for false:FalseClass
>>> (NoMethodError)
>
>> I think this has something to do with the implementation of
>> Range#include? (being that it returns rng.start <= val <= rng.end)
>
> But I think Range#include? should catch the Exception and return false
> instead.
>
>> An easy way around it is to use ('a'..'z').entries.include?(1)
>> instead
>
> That does not work when Range#start is a Float (and it builds an
> additional Array)

Also, there are several equally valid interpretations of Range#include?:

 - True, if the range while iterating yields the specific value (std
definition from Enumerable)

 - True, if low <= x <= high

 - True, if low < x <= high

....

So maybe Range#include? is not that useful after all...  Or we should
leave the std definition from Enumerable in place and introduce
Range#contains? or Range#covers? to deal with the more range specific
interpretations.

Kind regards

    robert