rubinius

Comments and changes to this ticket

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  Ryan Davis June 23rd, 2008 @ 04:10 PM

  • → Assigned user changed from “” to “Ryan Davis”
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  This has been marked as spam

  salad October 14th, 2008 @ 07:35 AM

  • → Tag changed from “” to “numeric”

  And Comparable uses Numeric#== (among other things) to define >, <, etc. This is not a bug.

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  Ryan Davis June 29th, 2008 @ 09:37 PM

  I tend to agree...

  Also, you need a better username. We're not borg.

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  Arthur Schreiber June 30th, 2008 @ 12:15 AM

  @7: No, that's not true. Comparable defines #==. Comparable uses the spaceship operator (that funky #<=> method), as noted above, to define #>, #<, #==, etc.

  I tried to fix that, but it was just too much of an headache, heh.

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  Ryan Davis June 30th, 2008 @ 01:33 AM

  Comparable depends on spaceship (<=>) to do it's work, which returns [-1, 0, 1]. So to define the other Comparable methods, you need to be able to compare against those fixnums:

      le <= 0 (or != 1)
      lt == -1
      eq == 0
      gt == 1
      ge >= 0 (or != -1)
  

  So, technically, I guess you can just have Fixnum#== assuming spaceship never ever takes any shortcuts.

  (argh I hate the formatting system in lighthouse--and yes, the compose page is MUCH better by not linking to a quickref. asshats)

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  Arthur Schreiber June 30th, 2008 @ 05:20 AM

  Not sure whether we're thinking the same thing. :)

  Numeric#<=> should only return 0 if self#equal?(other) is true, nil otherwise. If you now include Comparable into Numeric, everything is fine and works like in MRI.

  Numeric should not define #==, #<, #>, #<= or #>= (it currently does), as these get defined by the Comparable module (which will use Numeric#<=> internally).

  All (Core)-Numeric subclasses should then define their own (modified) #<=> method, which will get used by the Comparable methods.

  Fixnum itself can also redefine all comparison methods (as it does in MRI) for increased performance when doing type-conversions or whatever you want it to do. (Which, as noted by you, could actually be all handled inside Fixnum#<=>).

  One thing that I think is weird is that all the Numeric subclasses define their own #<=> and #== method, as they could simply rely on #== being defined by Comparable and using #<=> internally.

  I hope this clarifies things up a bit. :)