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[feaLib] Minor parser refactoring in preparation for GPOS type 5

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GPOS type 5 has much in common with GPOS type 4, so we want to share
the common parsing code.
This commit is contained in:
Sascha Brawer 2015-12-08 23:46:04 +01:00
parent 0fbbe037bf
commit 25acebd824
1 changed files with 42 additions and 31 deletions
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73
Lib/fontTools/feaLib/parser.py
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@ -88,6 +88,16 @@ class Parser(object):
return ast.Anchor(location, x, y, contourpoint,
xDeviceTable, yDeviceTable)
def parse_anchor_marks_(self):
"""Parses a sequence of [<anchor> mark @MARKCLASS]*."""
anchorMarks = [] # [(ast.Anchor, markClassName)*]
while self.next_token_ == "<":
anchor = self.parse_anchor_()
self.expect_keyword_("mark")
markClass = self.expect_markClass_reference_()
anchorMarks.append((anchor, markClass))
return anchorMarks
def parse_anchordef_(self):
assert self.is_cur_keyword_("anchorDef")
location = self.cur_token_location_
@ -268,39 +278,12 @@ class Parser(object):
def parse_position_(self, enumerated, vertical):
assert self.cur_token_ in {"position", "pos"}
location = self.cur_token_location_
if self.next_token_ == "cursive": # GPOS type 3
self.expect_keyword_("cursive")
if enumerated:
raise FeatureLibError(
'"enumerate" is not allowed with '
'cursive attachment positioning',
location)
glyphclass = self.parse_glyphclass_(accept_glyphname=True)
entryAnchor = self.parse_anchor_()
exitAnchor = self.parse_anchor_()
self.expect_symbol_(";")
return ast.CursiveAttachmentPositioning(
location, glyphclass, entryAnchor, exitAnchor)
if self.next_token_ == "base": # GPOS type 4
self.expect_keyword_("base")
if enumerated:
raise FeatureLibError(
'"enumerate" is not allowed with '
'mark-to-base attachment positioning',
location)
base = self.parse_glyphclass_(accept_glyphname=True)
marks = []
while self.next_token_ != ";":
anchor = self.parse_anchor_()
self.expect_keyword_("mark")
markClass = self.expect_markClass_reference_()
marks.append((anchor, markClass))
self.expect_symbol_(";")
return ast.MarkToBaseAttachmentPositioning(location, base, marks)
return self.parse_position_cursive_(enumerated, vertical)
elif self.next_token_ == "base": # GPOS type 4
return self.parse_position_base_(enumerated, vertical)
location = self.cur_token_location_
gc2, value2 = None, None
gc1 = self.parse_glyphclass_(accept_glyphname=True)
if self.is_next_glyphclass_():
@ -322,6 +305,34 @@ class Parser(object):
return ast.PairAdjustmentPositioning(location, enumerated,
gc1, value1, gc2, value2)
def parse_position_cursive_(self, enumerated, vertical):
location = self.cur_token_location_
self.expect_keyword_("cursive")
if enumerated:
raise FeatureLibError(
'"enumerate" is not allowed with '
'cursive attachment positioning',
location)
glyphclass = self.parse_glyphclass_(accept_glyphname=True)
entryAnchor = self.parse_anchor_()
exitAnchor = self.parse_anchor_()
self.expect_symbol_(";")
return ast.CursiveAttachmentPositioning(
location, glyphclass, entryAnchor, exitAnchor)
def parse_position_base_(self, enumerated, vertical):
location = self.cur_token_location_
self.expect_keyword_("base")
if enumerated:
raise FeatureLibError(
'"enumerate" is not allowed with '
'mark-to-base attachment positioning',
location)
base = self.parse_glyphclass_(accept_glyphname=True)
marks = self.parse_anchor_marks_()
self.expect_symbol_(";")
return ast.MarkToBaseAttachmentPositioning(location, base, marks)
def parse_script_(self):
assert self.is_cur_keyword_("script")
location, script = self.cur_token_location_, self.expect_script_tag_()