I'd like to write an elisp-function that has a function as argument and returns a new function.
Let's say the new function
double-the-function should write the returned value of the argument-function twice.
(The argument function operates on a string and returns a string. This is ensured.)
(reverse "abc") returns:
If I define the function
f as follows:
(setq f (double-the-function reverse))
I expect that:
(f "abc") returns
which is equal to
(concat (reverse cba) (reverse "cba")).
How to define