21 Sep
2007
21 Sep
'07
2:46 a.m.
G'day all.
Quoting Stefan O'Rear
The reason ++ and mplus is so similar is that they used to be the same; (++) *was* the MonadPlus class member. Cale Gibbard explains this as {{{Quite a few people on the Haskell 98 committee had an irrational fear of polymorphism.}}}
That's a slight exaggeration. They actually had nightmares involving trying to explain to their undergraduate students what the inevitable type error messages meant. At a time when Haskell was mostly a teaching/research language, this made a certain amount of sense. Now that Haskell is officially Cool(tm), the argument is much weaker. Cheers, Andrew Bromage