monad syntax extension

[neodymion]

allow this:

print (readInt [<getLine>] + readInt [<getLine>])

(or some other kind of funky brackets) to translate into

getLine>>=\x->getLine>>=\y->print (readInt x + readInt y)

[NeilMitchell]

This is the kind of thing that should be discussed, and refined, perhaps on a wiki, before raising a bug for it.

I've seen Simon PJ talk about the syntax:

print (readInt (<- getLine) + readInt (<- getLine))

There was a whole discussion on it, which raised things like which do block are these floated to, and now do x /= x by a very long way.

[claus]

And if you believe the advocates of Control.Applicative, this becomes:

>let readInt a = read a::Int
>:m +Control.Applicative
>print =<< ((+) <$> (readInt <$> getLine) <*> (readInt <$> getLine))
1
2
3

or even

>:set -XNoMonomorphismRestriction
>let (+) = liftA2 (Prelude.+)
>print =<< ((readInt <$> getLine) + (readInt <$> getLine))
2
3
5

[igloo]

I agree with Neil; I think a design needs to be worked out in another forum before it is useful to have a ticket for this.