There has been a long standing (since the beginning of the project?)
issue with sharing schematics between projects. It has been somewhat
supported for complex hierarchies (a sheet shared multiple times in a
single design) but it has not been well supported for simple hierarchies
(the symbol references cannot be changed in the shared schematic). This
issue has been resolved by moving all of the symbol instance sheet paths
from the symbol definitions in the all of the project files and save all
symbol path instances in the root sheet. This ensures that orphaned
symbol instance paths do not accumulate in shared schematic files and
that designs that reuse schematic in simple hierarchies can how have
different references. It also allows the root schematic from one project
to be uses as a sub-sheet in another project.
When legacy schematics are loaded, all sheet and symbol UUIDs are
converted from time stamps to true UUIDs. This is done to ensure there
are no sheet path instance clashes between projects. That being said,
there are no checks for this. It is assumed that the probability of
UUID clashes is so low that it doesn't make sense to test for them.
This is a very large and potentially disruptive change so this will be an
unusually long and detailed commit message.
The new file formats are now the default in both the schematic and symbol
library editors. Existing symbol libraries will be saved in their current
format until new features are added to library symbols. Once this happens,
both the legacy schematic and symbol file formats will be no longer be
savable and existing libraries will have to be converted. Saving to the
legacy file formats is still available for round robin testing and should
not be used for normal editing.
When loading the legacy schematic file, it is imperative that the schematic
library symbols are rescued and/or remapped to valid library identifiers.
Otherwise, there will be no way to link to the original library symbol and
the user will be required manually set the library identifier. The cached
symbol will be saved in the schematic file so the last library symbol in
the cache will still be used but there will be no way to update it from the
original library.
The next save after loading a legacy schematic file will be converted to
the s-expression file format. Schematics with hierarchical sheets will
automatically have all sheet file name extensions changed to .kicad_sym
and saved to the new format as well.
Appending schematics requires that the schematic to append has already been
converted to the new file format. This is required to ensure that library
symbols are guaranteed to be valid for the appended schematic.
The schematic symbol library symbol link resolution has been moved out of
the SCH_COMPONENT object and move into the SCH_SCREEN object that owns the
symbol. This was done to ensure that there is a single place where the
library symbol links get resolved rather than the dozen or so different
code paths that previously existed. It also removes the necessity of the
SCH_COMPONENT object of requiring any knowledge of the symbol library table
and/or the cache library.
When opening an s-expression schematic, the legacy cache library is not
loaded so any library symbols not rescued cannot be loaded. Broken library
symbol links will have to be manually resolved by adding the cache library
to the symbol library table and changing the links in the schematic symbol.
Now that the library symbols are embedded in the schematic file, the
SCH_SCREEN object maintains the list of library symbols for the schematic
automatically. No external manipulation of this library cache should ever
occur.
ADDED: S-expression schematic and symbol library file formats.
I could not find a reasonable solution to the mandatory field canonical
name issue so field indices are back in play as much as I did not want
to use them. They really only have meaning for the mandatory fields.
For all other fields, the index number is meaningless and the field name
is the primary means for searching.
Fix a broken field size bug in the symbol library formatter.
Please note that the symbol cache is not embedded in the schematic file
to allow for round robin testing with the existing file format. Once
the parser round robin testing is complete, the symbol cache will be
embedded in the schematic file.
This implements all existing symbol library object support and the ability
to save and load symbol library files between file formats for round robin
testing.
CHANGES: Symbol library file format has been converted to s-expressions.
Add support code for picking apart symbols at some future junction that
will allow full inheritance conversion of existing symbol libraries. For
now, symbols arranged by unit and body style numbers are nested for round
robin testing of symbol libraries once the parser is complete.
Jeff Young
Wayne Stambaugh