Eugene - Yes, that is special syntax only for ports (aka terminals).
One typical use of a current sensor is a controlled source:
Code:module ccvs(in, out);
inout in, out;
electrical in, out;
parameter real gain = 1;
analog begin
V(out) <+ gain * I(in); // shorts "in" to ground
end
endmodule
As noted before, this shorts "in" to ground, and then measures the current flowing through this shorted branch to generate the output voltage.
One might use the I(<port>) syntax in a more complicated module
Code:module bjt(c,b,e);
inout c,b,e;
electrical c,b,e;
real ic, ib, ie;
analog begin
// put BJT equations here
ic = I(<c>);
ib = I(<b>);
ie = I(<e>);
$strobe("Terminal currents: i(c)=", ic, " i(b)=", ib, " i(e)=", ie);
end
endmodule