snap framework - What is <|> in haskell? -


i still learning haskell , looking @ snap web framework. in hello world example there thingy looks <|>

site :: snap () site =     iftop (writebs "hello world") <|>     route [ ("foo", writebs "bar")           , ("echo/:echoparam", echohandler)           ] <|>     dir "static" (servedirectory ".")

googling surprisingly challenging, , snap documentation uses <|> noun. it, , do?

it's method in alternative typeclass in module control.applicative in base package.

typically means you're dealing kind of computation can fail , continue. if both x , y typed m a m tags kind of computation we're talking then

x <|> y :: m

is computation "tries" x , if fails "tries" y. such kinds of computation instantiate alternative.


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