Mathematica functions for using the "mathematica" exporter of gEDA and Lepton-EDA
You'll need either geda-gaf (see http://wiki.geda-project.org/geda:gaf) or Lepton-EDA (see https://github.com/lepton-eda/lepton-eda).
To make the netlist from the sample schematic, from the command line issue:
gnetlist -g mathematica Shaper.sch -o Shaper.m (geda-gaf)
or
lepton-netlist -g mathematica Shaper.sch -o Shaper.m (Lepton)
To reduce the circuit equations to a model, see gEDAmath.nb.
This predates Mathematica system models, but it can produce a transfer function expression suitable as input to the system modeling machinery.