Maps a function over the range of a finite partial function
DESCRIPTION
This is one of a suite of operations on finite partial functions, type
('a,'b)func. These may sometimes be preferable to ordinary functions since
they permit more operations such as equality comparison, extraction of domain
etc. The function mapf f p applies the (ordinary OCaml) function f to all
the range elements of a finite partial function, so if it originally mapped
xi to yi for it now maps xi to f(yi).
FAILURE CONDITIONS
Fails if the function fails on one of the yi.
EXAMPLE
# let f = (1 |=> 2);;
val f : (int, int) func =
# mapf string_of_int f;;
val it : (int, string) func =
# apply it 1;;