Re:Haskell tutorial for C programmers
by judk on Sunday May 11, 2014 @01:38AM
(#7727893)
E) you do get a dilemma if you add two elements in a sorted structure , lexically in two different files, where two different Ord instances arr in scope, respectively. this function-is-instance problem is dual to OO's -object-is-instance problem.
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A homogenous list is guaranteed to only have one instance unless you enable incoherent instances (a known bad extension) or confuse the compiler with orphan instances (though I've never encountered this and think it should be detectable at link time anyway).
One type -> at most one instance for any class, in Haskell.