Function: printsep
Section: programming/specific
C-Name: printsep
Prototype: vss*
Help: printsep(sep,{str}*): outputs its string arguments (in raw format),
 separated by 'sep', ending with a newline.
Doc: outputs its arguments in raw format, ending with a newline.
 The arguments are converted to strings following the rules in
 \secref{se:strings}. Successive entries are separated by \var{sep}:
 \bprog
 ? printsep(":", 1,2,3,4)
 1:2:3:4
 @eprog
