Nodes of different colours represent the following:
Solid arrows point from a submodule to the (sub)module which it is
descended from. Dashed arrows point from a module or program unit to
modules which it uses.
program volatile_doctestuse vecfor_R16Ptype(vector_R16P)::ptpt=ex_R16P+ey_R16Pcall pt%printf(prefix='[x, y, z] = ',sep=', ')endprogram volatile_doctest