SPICE syntax and grammer

I have no idea what "a formal Backus-Naur style syntax" is.

Are you speaking of "commands" such as .TRAN, etc?

If that is what you are after, the various SPICE's have the same command line structure, except that HSpice has a few additional ones, .ALTER for instance, that I wish PSpice had :-(

...Jim Thompson

Hi,

The backus-naur grammar format specifies exactly how a spice parser would read in the text file and create the data structures representing the circuit.

For instance, a parameter list would be something like:

PARMLST:=PARMLST TUPLE | TUPLE

TUPLE:= VAR '=' NUM

VAR = non-keyword NUM = number

So this means a PARMLIST consists of another parmlist and a tuple, or just a tuple. A tuple is a variable followed by an equals sign followed by a number. With these rules it's possible to describe most computer languages and stuff. I'm sure SPICE has one, but I haven't been able to find it.

thanks ms

Seems that would be a function of how closely the software writers adhered to the original Berkeley approach which, IIRC, was written in Fortran. I know that PSpice was re-written in C. I don't know about other SPICE's.

...Jim Thompson

I doubt that you can. I had a look some time ago, and one stumbling block is the fact that tokens can mean different things depending on where they occur. While it is possible to describe grammers with this property in some scanner/parser generator systems, I doubt that BFN or its ilks will do.

Consider

R R 0 R

which describes a resistor (line starts with 'R') from node R to node 0 with the value R. This is legal in hspice input language and other extensions of the Berkeley Spice input language (expecting a defintion of the value of the parameter 'R,' of course) but makes scanning/parsing a challenge.

I would love to see such a grammar, but didn't find one when I was looking for it.

That said, the original Berkely Spice 2 accepted such a simple input language that a formal description should be possible.

Best Regards

Jens

"Jens Tingleff" a écrit dans le message de news: snipped-for-privacy@drn.newsguy.com...

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We once developped a library maintaining tool and went to exactly the same conclusion.

OTOH I just googled for "spice grammar" + parser and found a message (dated