Nodes of different colours represent the following:
Solid arrows point from a file to a file which it depends on. A file
is dependent upon another if the latter must be compiled before the former
can be.
program volatile_doctestuse penf_stringifyuse penfcharacter(len=:,kind=UCS4),allocatable::stringstring=str_ascii(ASCII_'I was ASCII kind, but now I am UCS4')print"(A)",stringendprogram volatile_doctest