[Haskell-cafe] Data constructor synonyms
andres.loeh at googlemail.com
Fri Mar 18 14:44:11 CET 2011
>> Remember that constructors are functions, except that you can't
>> pattern match against them.
>> The downside is that you can't pattern-match against these functions.
> The thing is that I need pattern matching, just functions won't do.
It's "only" a preprocessor, but Conor's "she" allows pattern synonyms:
> Anyway, a new question arose. If I have already declared a type, can I add new constructors to it from other modules?
Again, not within Haskell itself. "she" also has a feature that allows
something like this. There are various other techniques or proposals.
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