cons
Lib.cons : 'a -> 'a list -> 'a list
Curried form of list cons operation.
In some programming situations it is handy to use the "cons" operation
in a curried form. Although it is easy to code up on demand, the cons
function is provided for convenience.
Failure
Never fails.
Example
> map (cons 1) [[],[2],[2,3]];
val it = [[1], [1, 2], [1, 2, 3]]: int list list