This is a GlyphsApp extension, (partially) documented [here][1], but it is a
useful one as it allows concise glyph insertion using decomposition
without having to maintain the list of glyphs in two places. E.g.
```fea
@upper = [A-Z];
lookup insert {
sub @upper by @upper connector;
} insert;
feature ccmp {
sub @upper' lookup insert x;
} ccmp;
```
As apposed to:
```fea
@upper = [A-Z];
lookup insert {
sub A by A connector;
sub B by B connector;
sub C by C connector;
sub D by D connector;
sub E by E connector;
sub F by F connector;
sub G by G connector;
sub H by H connector;
sub I by I connector;
sub J by J connector;
sub K by K connector;
sub L by L connector;
sub M by M connector;
sub N by N connector;
sub O by O connector;
sub P by P connector;
sub R by R connector;
sub S by S connector;
sub T by T connector;
sub U by U connector;
sub V by V connector;
sub W by W connector;
sub X by X connector;
sub Y by Y connector;
sub Z by Z connector;
} insert;
feature ccmp {
sub @upper' lookup insert x;
} ccmp;
```
1. http://handbook.glyphsapp.com/en/layout/multiple-substitution-with-classes/
Fixes https://github.com/fonttools/fonttools/issues/2949
- If there are no marked glyphs in an "ignore" statement, issue a
warning. The spec disallows this but makeotf allows it. It is most
likely a typo, so a warning is warranted.
- Mark the first glyph not all the glyphs, this matches makeotf.
- In asFea() always mark the input glyph.
- Udpate the tests.
* add test that fails for #2293
* fixing #2293: rewrite of contextual positioning logic, ensure len(suffix) > 1 yields the correct result; checking more edge cases and raising errors inspired by makeotf
* test error cases
* only check when we actually have a value
* catch one more case that makeotf errors on and we didn't
This makes the directory to search for included files explicit.
Also use Python 3's FileNotFoundError to catch non-existant files instead of a workaround for Python 2.
This allows for more than one "lookup ..." chaining statements at each glyph position in a chaining contextual substitution or positioning rule: e.g.
sub a b c' lookup lookup1 lookup lookup2 d;
The corresponding change in the Adobe OpenType Feature File Specification (and implementation in makeotf) happened in adobe-type-tools/afdko#1132.
This checks that glyph names that appear in a feature file are actually
in the glyph set provided in glyphNames. If the set is empty, no check
is done. This preempts a KeyError later during saving of a TTFont object
and makes this case much more easily catchable.
Closes#1723.
If the single substitution involved a glyph class, we were incorrectly
using only the first glyph in the class.
Broken since ec6ff821f0e72022d7aec8794b6bb589d8f81808, apparently no one
else uses this feature!
ValueRecord had a makeString() method that takes an optional “vertical”
argument, but no code outside the tests sets this argument. Renamed it
to asFea() and dropped the “vertical”, so that it consistent with the
rest of feaLib.ast classes.
Currently, the feature file parser always resolves included files,
parses their content and inserts it in the resulting AST. The original
`include` statement is lost.
This commit introduces an option to not follow inclusions. Instead, the
output AST will contain an `include` statement. This allows to process a
feature file on its own, and allows to round-trip it.
For example in glyphsLib, when going from a UFO to a .glyphs file, a
UFO feature file will be sliced up into Glyphs.app classes (e.g. a
GSFeaturePrefix with code `include(../family.fea);`) and when going back
from .glyphs to UFO, the feature file will be patched back together.
As Martin Hosken reported in https://github.com/fonttools/fonttools/pull/1096,
feaLib currently incorrectly handles the case where a marked input
glyph sequence in a contextual chaining sub/pos rule is split into
multiple runs, rather than being a single continuous run of ' marked
glyphs.
The consensus there was to raise a syntax error like makeotf instead of
second-guessing and silently fixing it like fontforge does.
... instead of a glyphMap dict.
The parser does not actually need a reverse glyph order mapping as
it is not interested in knowing the glyphID from the glyph name,
but only whether a glyph is in the font or not.
This makes it easier for client code (e.g. ufo2ft feature compiler)
to use the feaLib Parser, without having to first construct and pass
it a glyphMap argument.
Before this change, the following glyph class:
@Vowels = [@Vowels.lc @Vowels.uc y Y];
Would be written back as:
@Vowels = [@Vowels.lc = [a e i o u]; @Vowels.uc = [A E I O U]; y Y];
Which is clearly invalid. It seems for GlyphClass.asFea() to work
correctly here we should be using GlyphClassName not GlyphClass
for the nested classes (similar to the code at the beginning of
parse_glyphclass_()).
The syntax tree representation now reflects the syntax of feature files.
Before this change, FeatureNames did not have their own `ast.Block`,
which had made the code quite messy.
Before this change, some table statements would allow empty statements
(just a semicolon) while others would not allow them. After this change,
we're more consistent.
