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Re: Get the real object in a Hash key

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Robert K. wrote in post #993026:
> I did not argue against complex keys.  The issue is with *mutable*
> keys.  And since adding data to the key object is also associating
> (which is done with the value as well) the most natural way would be
> to place that additional information there.  Not to mention the
> questionable approach to stuff something into what is usually
> considered a simple value (String).

You said "And you don't want to do it." In fact doing it has its uses.
Mutable keys or not is totally irrelevant, especially when the data
was there before the hash was introduced, as in the original example.

*Of course* making repeated calls to Hash#assoc in order to update
stuff in the key would be stupid. That goes without saying. What would
the purpose of the hash be? If that was your only point then we agree,
although it was a vacuous point.

Also do you realize that an example tends to stand for something which
is not literally the example itself? He has a key. It contains some
data. It's not necessarily true that he should duplicate that data in
the mapped-to values. Mutable or not is beside the point.

I notice this phenomenon a lot: undergeneralization. The String stands
for something. It's his key data. If it were a simple value then the
example wouldn't make sense in the first place. Gee, thanks for
telling us that we shouldn't stuff random shit into a simple value and
then use that as a hash key, whereupon we can't look up stuff in the
hash directly but must use Hash#assoc instead. Again, if that was your
point then we agree, albeit in the obvious and nearly information-free
sense. I'm sure we would also agree that cats would be a poor building
material for helicopters.

-- 
Posted via http://www.ruby-forum.com/.

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Thread

Get the real object in a Hash key Iñaki Baz Castillo <ibc@aliax.net> - 2011-04-15 07:50 -0500
  Re: Get the real object in a Hash key Robert Klemme <shortcutter@googlemail.com> - 2011-04-15 08:00 -0500
    Re: Get the real object in a Hash key Iñaki Baz Castillo <ibc@aliax.net> - 2011-04-15 08:14 -0500
      Re: Get the real object in a Hash key Robert Klemme <shortcutter@googlemail.com> - 2011-04-15 08:48 -0500
        Re: Get the real object in a Hash key Iñaki Baz Castillo <ibc@aliax.net> - 2011-04-15 09:46 -0500
        Re: Get the real object in a Hash key Kevin Mahler <kevin.mahler@yahoo.com> - 2011-04-15 09:47 -0500
          Re: Get the real object in a Hash key Robert Klemme <shortcutter@googlemail.com> - 2011-04-15 11:08 -0500
            Re: Get the real object in a Hash key Kevin Mahler <kevin.mahler@yahoo.com> - 2011-04-15 12:39 -0500
              Re: Get the real object in a Hash key Robert Klemme <shortcutter@googlemail.com> - 2011-04-16 15:20 +0200
              Re: Get the real object in a Hash key Iñaki Baz Castillo <ibc@aliax.net> - 2011-04-16 09:51 -0500
                Re: Get the real object in a Hash key Robert Klemme <shortcutter@googlemail.com> - 2011-04-16 18:15 +0200
                Re: Get the real object in a Hash key Iñaki Baz Castillo <ibc@aliax.net> - 2011-04-16 11:55 -0500
                Re: Get the real object in a Hash key Josh Cheek <josh.cheek@gmail.com> - 2011-04-16 11:17 -0500
  Re: Get the real object in a Hash key jake kaiden <jakekaiden@yahoo.com> - 2011-04-16 10:28 -0500

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