| ID: | 1217 |
| From: | ge...@igor2.repo.hu |
| Date: | Sun, 7 Jan 2018 05:10:23 +0100 (CET) |
| Subject: | Re: [pcb-rnd] default clearance in new subcircuit footprints, fixing |
| in-reply-to: | 1215 from John Griessen <jo...@cibolo.com> |
| replies: | 1262 from ge...@igor2.repo.hu |
On Sat, 6 Jan 2018, John Griessen wrote:
> I'm finding default clearance, (the distance polygons will open up away from a
> line)*2, is 40 mils.
>
> I'm not sure where to change this. Anyone know?
It's in the config tree, under design/clearance; this value is the actual
clearance, the no-copper width on each side of new objects.
>
> Also I want to make a script to change past ones I've made and awk seems
> difficult since the task is to
> make a change 'inside braces starting here until close braces found',
> and awk's line by line operation means counting braces found to decide what to
> do, which sounds difficult.
>
> What do you experienced programmers do for changing just the layer top in a
> lihata file?
> I want to find and replace
> %s/clearance = 40mil/clearance = 0.3mm/g
> %S/clearpoly =/clearpolypoly =/g
(I write a longer essay, sorry for the wall-of-text, because I am going to
convert it to a pool node)
Unfortunately line based processing is unsafe for tree structured files
like lihata files. It's the same problem as with any other structured
files (like xml, or C source code).
You have the following choices:
1. use a line based processing and depend on the formatting of the file (a
bit risky!); Peter Stuge posted and excellent example. It will work most
of the times, but there would be some files on which it breaks. For
example it is possible to write '{' or '}' in text strings in lihata, and
such a script will not understand that and will think it's an opening or
closing brace; it's also possible to assing the clearance value with '='
or without '=', or to protect the value with {}. You can also have a
protected newline (backslash and newline) in between any two field. If you
want to go this way, I recommend using the 'save as' function in pcb-rnd
first, with a new file name, to get a relatively clean formatting.
(Background: the decision for such a non-line-based format was hard last
year - I love to write awk scripts too, all our web services are based on
CGI scripts running awk scripts deep inside. But I had to realize the
limitations of the old file format could not be solved unless we switched
to a format that has named fields and can represent arbitrary deep trees
easily. I accepted this mostly because I knew I'd provide the options
listed below)
2. use the GUI! These features are not very well tested in practice, but
are available for a very long time already: use the advanced search to
select all interesting object. You can easily craft a search expression
that selects all top copper objects. You even get a GUI if you don't want
to learn the query syntax (which is among the few things that are really
well documented in pcb-rnd). Once you have your mega-selection, use the
property editor (ctrl-e) to change the clearance of all selected object to
fixed value.
3. use the CLI! The above features, both the query based selection and the
property edition are accessible from the command line, without any GUI or
dialog box involved. What you want to do can be done by executing two
action calls. Can be done even from the batch HID, fully automatically.
Which means you can easily write a shell script that runs pcb-rnd, loads
your design, searches-and-selects, change properties, save and exit. Which
means you get a shell script converter tool that is guaranteed to
understand any past or future file format. It's just written in pcb-rnd
action script, not in awk.
4. use a language that really parses and understands the tree; at the
moment we don't have too mnay bindings for lihata, but lihata is so small
and trivial that it's rather easy to implement new bindings. The only one
direct language binding is to php. But what we also have is fungw binding,
which allows automatic binding to any language fungw supports. This is not
a long list yet: a somewhat tested lua binding and untested libmawk and
tcl bindings. I would happily accept contribution to fungw language
bindings!
5. use scripting from within pcb-rnd; gpmi is not in good shape at the
moment, so this probably won't work out-of-the-box. When it used to work a
year ago, it was like this: you could write, in one of 10 languages, awk
included, a script that ran within pcb-rnd and accessed and manipulated
data right in the memory. So it's like writing a plugin not in C but in
your favorite language. You could have written a script that iterated on
top copper objects and changed clearance.
One of my plans for 2018, especially after finishing the data model
switchover, to get sciprting to work again. It's a stretegic field where
pcb-rnd can easily beat any other PCB package (because even if they
support scripting, they usually support only one language).
(Background: unfortunately the user demand behind scripting turned out to
be much lower than the user demand behind the data model rewrite and I/O
plugins. Meanwhile I started to replace gpmi with fungw+puplug. The full
history is that I originally had gpmi scripting as a plugin, on top of pcb
first (circa 2010 or so) then on top of pcb-rnd. But I always felt like it
was a waste that gpmi had a much better plugin arch than pcb (or later
pcb-rnd) had. So I felt the good choice is not putting gpmi on top of pcb
but put pcb on top of gpmi. I figured soon enough that it was hopeless to
get mainline to accept this, so I went with the gpmi-on-top-of-pcb
approach. Then after the pcb-rnd fork, I realized the way to swap the
stack is to split gpmi in two separate libs: one that does the plugin
system only, puplug, and another that does the call dispatching only,
fungw. This way it was easier to replace the old plugin system in pcb-rnd,
we already use puplug for a long time, but becuase of the low user demand,
fungw is not up to speed yet)
6. partial solution: lhtflat; lhtflat is an utility distributed with
lihata. It properly parses a lihata document and renders it in a
different, flat text file format that is suitable for line based
processing. It was invented exactly for the case when you want to use awk
(or other languages that don't yet have lihata bindings). The solution is
partial, because we don't yet have a way to convert a flat file back to
lihata - so you can use ti to read out values but not to make
modifications.
HTH,
Igor2
Reply subtree:
1217 Re: [pcb-rnd] default clearance in new subcircuit footprints, fixing from ge...@igor2.repo.hu
1262 Re: [pcb-rnd] default clearance in new subcircuit footprints, fixing from ge...@igor2.repo.hu
1263 Re: [pcb-rnd] default clearance in new subcircuit footprints, fixing from John Griessen <jo...@cibolo.com>