Writing to a file or a string with the same function

[Beliavsky]

@urbanjost

I use a function STR that returns a string and can take up to twenty intrinsic scalars.

Neat. I have sometimes wished to write a Fortran procedure that can take any number of arguments of any type. The built-in print statement has this feature. How @urbanjost does it is to declare many class(*),intent(in),optional arguments, as shown in his code

pure function msg_scalar(generic0, generic1, generic2, generic3, generic4, generic5, generic6, generic7, generic8, generic9, &
                       & generica, genericb, genericc, genericd, generice, genericf, genericg, generich, generici, genericj, &
                       & sep)
implicit none
class(*),intent(in),optional  :: generic0, generic1, generic2, generic3, generic4
class(*),intent(in),optional  :: generic5, generic6, generic7, generic8, generic9
...

His function takes up to 20 arguments, which is more than needed in almost all cases, but a code could be written to generate source code for a function that takes N > 20 arguments. So with automatic code generation you can get in Fortran some of the flexibility you have in Python.