In f0eb7e98ca0642f17ac82433db8c957fffd6a9d3, the various subclasses
of otTables.ClassDef were merged into one single class. Therefore,
we can now always instantiate otTables.ClassDef() which is simpler.
Make the output of otlLib.buildLigatureSubst() deterministic.
Before this change, otlLib ligatures were emitted in a non-deterministic
sorting order (depending on what hash value Python would give
to a string tuple).
After b4919b6c0a5ea0ca6747fe7699554e8a14d1f77f, the tests were
named correctly but they always used the exact same feature file,
irrespective of what file they were supposed to test.
Resolves https://github.com/behdad/fonttools/issues/465
Before this change, feaLib did not handle feature files that specified
`feature aalt` whose block just was referring to other features without
defining any lookups on its own. After this change, we can handle it.
Resolves https://github.com/behdad/fonttools/issues/441
Resolves https://github.com/behdad/fonttools/issues/445 for single
substitutions. The compact forms for chaining to other GSUB types
are not yet supported; these will get fixed in follow-up changes.
Before this change, we silently generated bad fonts. After this
change, we emit the exact same output like `makeotf` for specific
kerning pairs, and reject the input file for the not yet implemented
class-based kerning. (The implementation of class-based kerning
is coming soon).
Before this change, the compiler would enumerate only the first
glyph class of a kerning pair. However, that behavior did not match
the behavior of the `makeotf` tool.
Before this change, feaLib would sort coverage tables by glyph name,
which is against the OpenType specification. The current unittests
happen to use only glyphs where the ordering is identical whether
sorting by name or by ID; but I am about to add unittests (for GPOS)
where the ordering is different.
The ordering cannot be enforced by otTables because otTables does
not have access to the font's glyph order; therefore, the sorting
needs to happen inside feaLib.
Generated by running example 1 from the Feature File specification
section 5.f.i (Specifying a Chain Sub rule and marking sub-runs)
through AFDKO's makeotf tool, and then decompiling the resulting
GSUB table with ttx.
The actual test is commented out because the current version of feaLib
is not able to produce this output yet; marked with a TODO comment.
