Lift a pure two arguments function, to a function over lazy inputs.

Note that the only the first argument may be deeply forced. In particular it is deeply forced if the function use its second argument.

The strictness is here to enforce the evaluation order of reading inputs.

Since too much strictness breaks the interest of lazy inputs, one provides more specific but lazier combinators like append, interleave, and zip.

Lift a pure two arguments function, to a function over lazy inputs.

Note that the only the first argument is deeply forced before calling the function.

The strictness is here to enforce the evaluation order of reading inputs.

This lifting function can be generalized to n-ary functions, all arguments but the last one will be deeply forced.

 liftN f mx1 mx2 ... mxN = mx1 !>>= x1 -> mx2 !>>= x2 -> ... f x1 x2 $ mxN

Lift a pure two arguments function, to a function over lazy inputs.

Note that both arguments are deeply forced before calling the function. See lift2ForceFirst and lift2ForceSecond for lazier versions.

This one can also be generalized to n-ary functions:

 liftN f mx1 mx2 ... mxN = pureLI f ap' mx1 ap' mx2 ap' ... ap' mxN

Combines a function wrapped as a lazy input and an argument. This is like ap or <*> but stricter.

Note that since functions types are not member of NFData, this function is the only one dealing with functions wrapped as lazy inputs.

However as with ap or <*>, this function generalize lift2ForceSecond, lift3Fst...

Example: lift3Fst f x y z = f $ x ap' y ap' z lift3strict f x y z = pureLI f ap' x ap' y ap' z

The ap' function only deeply force the second argument, so in the case of chaining, the arguments will be forced from left to right. Note that if one starts the chain by lifting the function using pureLI, then all the arguments will be forced. One can let one of the arguments lazy by using note however that if one start the chain with <$> (same as fmap or liftM) then the first argument would not be forced, but one can start with pureLI