[Haskell-cafe] Question on definition of `parse' function in Parsec library.

[Yves Parès]

If I have this right, Stream is a monad transformer.
Stream s m t means that it parses 's', is stacked with monad 'm' and has a
result of type 't'

So Identity is a monad, the simplest monad, defined as such:

newtype Indentity t = Identity { runIdentity :: t }

It's the identity monad, that does nothing special but wrapping its result.


2011/10/8 Captain Freako <capn.freako at gmail.com>

> Hi all,
>
> In this definition from the Parsec library:
>
> parse :: (Stream s Identity t)      => Parsec s () a -> SourceName -> s -> Either ParseError aparse p = runP p ()
>
> what's the significance of `Identity t'?
> (`t' isn't used anywhere.)
>
> Thanks,
> -db
>
>
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