Anton van Straaten
anton at appsolutions.com
Tue Apr 8 10:32:13 EDT 2008
Hans Aberg wrote:
> There are two processes here: deriving, i.e., inheriting an interface;
> and instantiating, i.e., producing running code. Haskell denotes
> derivation by "=>". And "data <a> deriving (b_1, ..., b_k)" is really a
> short for
> data <a>
> instance b_1 where <compiler implementation>
> instance b_k where <compiler implementation>
> So "instance" seems the word that should have been used.
How about making "deriving x" an expression which means:
instance x where <compiler implementation>
This innovative solution will minimize changes to the Haskell compiler,
documentation, and programmer's brains.
Seriously, there's only so much connotational meaning you can pack into
or extract from a keyword. Ultimately, programming language keywords
follow the rule given by Humpty Dumpty:
"When _I_ use a word, it means just what I choose it to mean -- neither
more nor less."
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