fixspi

Sorts the instances inside every .subckt by group and number. Reads stdin, writes stdout; used by make spi.

xbber223a D G S B PMOS          xaber123a D G S B NMOS
xaber223a D G S B NMOS    ->    xaber223a D G S B NMOS
xaber123a D G S B NMOS          xbber223a D G S B PMOS

An instance name is split into a leading group (everything before the first digit or bracket) and a trailing number, and the lines are emitted grouped and then numerically ordered. A netlist that comes out in a stable order diffs cleanly against the previous run, which is the whole point.

On the way through it also:

joins + continuation lines into one line
uncomments **.subckt and **.ends, the same xschem quirk fixsubckt deals with
rewrites bus brackets <7> as _7

Comment lines inside a subcircuit are passed through in place. A line that does not parse raises an exception rather than being silently dropped.