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 stringifor_string_ttype(string)::astringtype(string)::anotherstringlogical::test_passed(1)astring='hello'anotherstring=astringtest_passed(1)=astring%chars()==anotherstring%chars()print'(L1)',all(test_passed)endprogram volatile_doctest