... 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.
We now correctly handle nameid statements with surrogate pairs and
old-style macOS-encoded names (provided that fonttools supports the
specified encoding).
Resolves https://github.com/fonttools/fonttools/issues/842.
* First round of adding fea output
No format tests but all test files give reasonable output so far.
* Get existing tests working
* Initial tests that work for fea2fea
* Get more tests working
Bug fixes and re-layout some tests to compare with fea2fea output.
Ranges and name parameters are not optimised yet.
* Handle vertical default values in fea2fea
* Hide fea2fea differences in lookupflags
* No reduce() in py3 so use a for loop
Fixes https://github.com/fonttools/fonttools/issues/457
Backslash-prefixed glyph name can be used in a Feature file to distinguish them from identically-named keywords.
From section "2.f.i. Glyph name" of Adobe's Feature File Specification:
> An initial backslash serves to differentiate a glyph name from an identical keyword in the feature file language. For example, a glyph named "table" must be specified in the feature file as: \table
Thus, when we parse a glyph name that begins with a backslash, we need to ignore the first character.
Note that makeotf rejects feature files with glyph names that start with or contain backslashes, even when escaped with another backslash.
feature liga {
sub \\glyphWithBackslash by A;
} liga;
This yields:
makeotfexe [FATAL] <Backslash-Regular> invalid token (text was "\") [features 2]
http://www.adobe.com/devnet/opentype/afdko/topic_feature_file_syntax.html#10
For example, @mhosken is interested in experimenting with inlining
custom syntax (such as Python snippets) into feature files. After this
change, such experiments can be done on top of feaLib because the
Abstract Syntax Tree now contains the tag and content of `anonymous`
blocks.
Before this change, we had only emitted a SinglePos (GPOS type 1) lookup
for a statement like `pos A' B' 20`; after this change, we always emit a
chain rule even if there is no context. There is a semantic difference if
the rule is preceded by a `ignore pos` statement. Omitting context-free
contextual chains was actually not a (premature) optimization, but an
artifact that came from the representation of glyph patterns.
https://github.com/behdad/fonttools/issues/516
Although this construct is in violation of the `ignore sub` grammar
given by the current OpenType Feature File syntax specification,
the very same specification document illustrates (in example 3
of section 5.f.ii) the `ignore sub` statement with a comma-separated
list of backgrack/input/lookahead triples.
See https://github.com/adobe-type-tools/afdko/issues/105 for a request
to amend the OpenType Feature File syntax specification.
After this code change, feaLib can now parse testdata/spec5f_ii_3.fea;
the output is identical to what is generated by Adobe's makeotf tool.
https://github.com/behdad/fonttools/issues/503
