From: brabuhr@...
Date: 2009-07-21T05:26:45+09:00
Subject: Re: getting char from string as fixnum in 1.8 and 1.9

On Mon, Jul 20, 2009 at 7:40 PM, Glenn Jackman<glennj@ncf.ca> wrote:
> At 2009-07-20 02:20PM, "Joel VanderWerf" wrote:
>>
>>  What's the best way to write this program so that it will run correctly
>>  on both 1.8 and 1.9? This works, but I'm just curious if there's
>>  anything better, preferably without the RUBY_VERSION test, without
>>  adding methods to String, and without losing much efficiency compared
>>  with 1.8's String#[].
>>
>>  if RUBY_VERSION =~ /\A1\.9/
>>     def third_char_as_fixnum(s)
>>       s[2].ord
>>     end
>>  else
>>     def third_char_as_fixnum(s)
>>       s[2]
>>     end
>>  end
>>
>>  s = "abc"
>>  p third_char_as_fixnum(s) # ==> 99
>
> This works in both 1.9.1 and 1.8.7
>
>     def third_char_as_fixnum(s)
>       s[2].ord
>     end
>
> Because Integer#ord returns the integer receiver.

> ruby -v -e 'p "foo"[2].ord'
ruby 1.8.6 (2007-09-24 patchlevel 111) [i386-linux]
-e:1: undefined method `ord' for 111:Fixnum (NoMethodError)

> cat foo.rb
unless 0.respond_to?(:ord)
  class Integer
    def ord; self; end
  end
end

> ruby -v -rfoo -e 'p "foo"[2].ord'
ruby 1.8.6 (2007-09-24 patchlevel 111) [i386-linux]
111

Still meets the constraint: "without adding methods to String"
:-)