Some simulators (LTspice, Pspice) accept a syntax for subcircuits that is incompatible with gnucap.
LTspice syntax:
Xv v1r v1i vri_slack params: ( vr=10 vi=1 on=1 vfactor=1.732 ) Ximp v1r v1i 0 0 impedance params: ( r=1 xl=10 xc=2 length=1 zfactor=1 )
The key params: should be omitted.
Gnucap syntax:
Xv v1r v1i vri_slack ( vr=10 vi=1 on=1 vfactor=1.732 ) Ximp v1r v1i 0 0 impedance ( r=1 xl=10 xc=2 length=1 zfactor=1 )
LTspice syntax:
.subckt impedance v1r v1i v2r v2i + params: + on = 1 + r = 100 + xl = 0
.subckt impedance v1r v1i v2r v2i params: on = 1 r = 100 xl = 0
The list of parameters is not accepted on the header line. Instead, list the parameters with .param statements on following lines.
Gnucap syntax:
.subckt impedance v1r v1i v2r v2i .param + on = 1 + r = 100 + xl = 0
.subckt impedance v1r v1i v2r v2i .param on = 1 r = 100 xl = 0