Re: gEDA-user: gerbv - abnormal exit (2nd attempt)

[Stefan Petersen <spe@xxxxxxxxxxxxxx>]

wilson1442@xxxxxxxxxxxxx wrote:
> Stefan Petersen wrote:
> 
>> 2) The aperture macro also contains operations like $4=$1X$5.
> 
> My copy of "Gerber Format: Plot Data Format Reference Book" is quite 
> old, (c)1993.  But some of the examples use the "$4=" construct to work 
> around the severe restriction on expressions:
> 
>    "Only one operator is allowed between commas.", and
>    "Only one operator is allowed on the right side of the equals sign."
> 
> If one wants to do anything remotely fancy, one almost has to use this 
> gimmick.  I wonder if these restrictions have been eased lately?  Even 
> simple left-to-right without operator precedence would be a big step up.

I think it is basically the latest version of the manual around. :) I 
have not done my homework properly and read the book as "the devil reads 
the bible". As the rewrite progress (other people are doing the job 
rewrite of the graphical stuff and other patching up here and there) I 
will look into this.


> I seem to remember running into this problem back with V1.0.2, and 
> thought I might take a whack at fixing it, but I recall gerbv is written 
> mostly in Scheme.  To me, it might as well have been written in 
> Boustrophedon.  I know that Scheme is a beautiful language, and I've 
> taken a couple of stabs at learning it, but  I still don't know my cdr 
> from a hole in the ground!

gerbv is written in plain C with GLib and GTK as extension. It uses 
Scheme currently for project files only. A long time you could write 
backends (to generate other files from the parsed gerber) in Scheme. But 
that broke a long time ago when I changed built-in Scheme interpreter.


Ah you saw the scheme directory and that scared you off. Look in the src 
directory and you be much relived. :)

Regards,
/Stefan


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