A hierarchical ACT file can be converted into a .sim and .al file for simulation with other open-source tools like irsim or cosmos.
Since .sim files correspond to a CMOS netlist, your production rules must be directly CMOS-implementable. This means that any pull-up network must have only inverted variables, and pull-down networks must have only uninverted variables. An explanation of how the production rules are translated into a transistor-level implementation can be found in the prs sub-language documentation as well as the documentation for the prs2net tool that creates a hierarchical SPICE netlist.
% prs2sim test.act test
will generate test.sim and test.al from test.act. Note that .sim files use / as the sub-circuit separator, and so prs2sim follows this convention.