The new version fixes some problems with the previous one, most notably
it can create a keyworded function when the last input is is keyworded.
`compose1' is a restricted variant that requires single values in the
composed pipeline -- besides being potentially faster (probably more
if/when there is cross module inlining), it has a semantical
justification, similar to the restricting function call arguments to
return single values, with similar robustness benefits. The
implementation of both is done in a generalized way, and the results can
be faster for both `compose' and `compose1'. (Not by much -- 20% and
30% resp.)
One thing that it could do is to reduce the resulting arity to match the
last given function. I didn't do this since it adds a significant
overhead to the result. (No strong opinion on doing that...)
Actually, the new `thunk' is a nullary function, which I think is very
popular expectation for the name. Since there are possible uses for the
any-arity version, it's added too, as `thunk*'.
