The syntax used for plotting parametric functions differs between Gnuplot and PyXPlot. Whereas parametric plotting is enabled in Gnuplot using the set parametric command, in PyXPlot it is enabled on a per-dataset basis by placing the keyword parametric before the algebraic expression to be plotted:
gnuplot> set parametric
gnuplot> set trange [0:2*pi]
gnuplot> plot sin(t),cos(t)
pyxplot> set trange [0:2*pi]
pyxplot> plot parametric sin(t):cos(t)
This makes it straightforward to plot parametric functions alongside non-parametric functions. For more information, see Section 1.6.