Nodes of different colours represent the following:
Solid arrows point from a procedure to one which it calls. Dashed
arrows point from an interface to procedures which implement that interface.
This could include the module procedures in a generic interface or the
implementation in a submodule of an interface in a parent module.
function flu_isNone(L,index)result(is_None)type(flu_State)::Linteger::indexlogical::is_Noneinteger(kind=c_int)::c_indexc_index=int(index,kind=c_int)! Only defined as a Macro, using lua_type:is_None=(lua_Type(L%state,c_index).eq.LUA_TNONE)end function flu_isNone