Re: [Gnucap-devel] Summer of code: Gschem analysis for parsing

[al davis]

On Monday 14 May 2012, address@hidden wrote:
http://gnucap.org/dokuwiki/doku.php?id=gnucap:user:language_plugin_for_gschem

(I need to make shorter URLs) ...

It looks like you are making good progress.  I am pleased with 
what I see.

a few comments ..

Mapping of geda "device" to verilog ...  

All you can do is pass it on.  There is no way of knowing info 
such as the symbol says "VOLTAGE_SOURCE" and Verilog needs 
"vsource".  All you can do is pass it on.  The symbol needs to 
be corrected, or there could be some way of mapping that is user 
controlled.  It could be as simple as "`define", but sometimes 
there could be node and parameter mapping as well ..

macromodule RESISTOR (\1, \2);
resistor (.r(r)) R1 (\1, \2);
endmodule

Note that I called it "macromodule" instead of "module".  For 
now, they are the same, but it is supposed to be that a 
"macromodule" is flattened, but a "module" preserves hierarchy.  
There are reasons for preferring one or the other.


Use of "place" ...

You cannnot rely on names (device names or node names) having 
any meaning.  They are just strings.  So (for example) the 
relation between "placeR1" and "R1" cannot be relied on.

This is why in my proposal 
http://gnucap.org/dokuwiki/doku.php?id=gnucap:user:netlist_import_and_export
I made the "place" locate the nodes, not devices.

A "place" connects to a node, and has locations as parameters.  
So, even if the names change it stays located.

I did not locate devices, only nodes.  The devices would float 
and place themselves reasonably between the nodes, which are 
explicitly located.

Back to the names ....  As I said, the names are just strings to 
the computer, but they do have meaning to humans.  I used a 
convention that nodes on the same net share the name of the net 
as the prefix, so a human reader can see that "n1" and "n2" are 
really the same net "n".  I thought that convention would be 
easier to comprehend for users who are accustomed to the spice 
notion that a net and node are the same.