[Haskell-cafe] Parsec: Where's +++?

[Donald Bruce Stewart]

garious:
> Koen Claessen's "Parallel Parsing Processes," suggests their parsing
> combinators have been integrated into Parsec.  If so, where is the +++
> operator hiding?

Hoogle says:

Control.Arrow.(+++) :: ArrowChoice a => a b c -> a b' c' -> a (Either b b') (Either c c')
Text.Html.(+++) :: (HTML a, HTML b) => a -> b -> Html
Text.ParserCombinators.ReadP.(+++) :: ReadP a -> ReadP a -> ReadP a
Text.ParserCombinators.ReadPrec.(+++) :: ReadPrec a -> ReadPrec a -> ReadPrec a
  
> Also, how do I determine what instances a datatype supports?  Is
> Parsec an instance of Applicative?

Try :info on your type in ghci:

    Prelude Control.Applicative> :info Applicative
    class (Functor f) => Applicative f where
      pure :: a -> f a
      (<*>) :: f (a -> b) -> f a -> f b
            -- Defined in Control.Applicative
    instance (Monad m) => Applicative (WrappedMonad m)
      -- Defined in Control.Applicative
    instance Applicative Maybe -- Defined in Control.Applicative
    instance Applicative [] -- Defined in Control.Applicative
    instance Applicative IO -- Defined in Control.Applicative
    instance Applicative ((->) a) -- Defined in Control.Applicative
    instance Applicative ZipList -- Defined in Control.Applicative

-- Don