module Extra:Extra definitions.sig
..end
val add_extension_if_absent : string -> string -> string
add_extension_if_absent filename ext
append to the string filename
the extension ext
but only if the filename has no already an extension.
This operation just works on strings and doesn't modify anything in the filesystem.
Example:
# add_extension_if_absent "foo" "txt";;
: string = "foo.txt"
# add_extension_if_absent "foo.c" "txt";;
: string = "foo.c"