Parser issue with functions

[jjg-123]

The parser allows for functions statements like f(3 4 5) (so spaces) and rather than issuing an error, it simply results in f(3) and silently discards the rest of it. Spaces in a list of function arguments should trigger an error.

In particular, if there are functions with the same name and different lists of arguments, this always chooses the monadic one silently.