Merge d598c2db5c into ba7f4b5f18
This commit is contained in:
Niels Thykier
GitHub
commit
f2e51dc7b1
1 changed files with 62 additions and 31 deletions
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@ -45,8 +45,6 @@ from __future__ import absolute_import
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import re
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from decimal import Decimal, getcontext
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from functools import partial
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# Sentinel.
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@ -59,10 +57,18 @@ class _EOF(object):
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EOF = _EOF()
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# default tokens
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# (name, default-token, regex pattern)
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lexicon = [
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('float', r'[-+]?(?:(?:[0-9]*\.[0-9]+)|(?:[0-9]+\.?))(?:[Ee][-+]?[0-9]+)?'),
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('int', r'[-+]?[0-9]+'),
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('command', r'[AaCcHhLlMmQqSsTtVvZz]'),
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('float', True, r'[-+]?(?:(?:[0-9]*\.[0-9]+)|(?:[0-9]+\.?))(?:[Ee][-+]?[0-9]+)?'),
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('int', True, r'[-+]?[0-9]+'),
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('command', True, r'[AaCcHhLlMmQqSsTtVvZz]'),
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# The "flag" token is defined as a single 0 or single 1. We
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# cannot parse this as a float or an int because those tokens
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# might consume multiple digits (e.g. "int, 11" instead of "flag,
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# 1" + "flag, 1") and the spec allows SVGs to omit the space after
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# a flag here.
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('flag', False, r'[01]'),
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]
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@ -80,22 +86,47 @@ class Lexer(object):
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def __init__(self, lexicon):
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self.lexicon = lexicon
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parts = []
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for name, regex in lexicon:
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for name, is_default, regex in lexicon:
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if is_default:
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parts.append('(?P<%s>%s)' % (name, regex))
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self.all_token_names = [x for x, _, _ in lexicon]
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self.single_token_rules = {x: re.compile('(?P<%s>%s)' % (x, y)) for x, _, y in lexicon}
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self.regex_string = '|'.join(parts)
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self.regex = re.compile(self.regex_string)
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def lex(self, text):
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""" Yield (token_type, str_data) tokens.
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"""Coroutine that yields (token_type, str_data) tokens.
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The parser can send a token name defined in the lexicon if the
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default token rules are not useful.
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The last token will be (EOF, None) where EOF is the singleton object
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defined in this module.
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"""
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for match in self.regex.finditer(text):
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for name, _ in self.lexicon:
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offset = 0
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current_pattern = self.regex
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while True:
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match = current_pattern.search(text, offset)
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if not match:
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break
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offset = match.end()
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for name in self.all_token_names:
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try:
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m = match.group(name)
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except IndexError:
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# Thrown if "name" is defined in the pattern.
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# This happens when the parser requests a
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# non-default token as the default token names are
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# tried before non-default ones.
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continue
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if m is not None:
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yield (name, m)
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pattern_request = (yield (name, m))
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if pattern_request is None:
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current_pattern = self.regex
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else:
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current_pattern = self.single_token_rules[pattern_request]
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break
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yield (EOF, None)
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@ -155,8 +186,8 @@ class SVGPathParser(object):
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""" Parse a string of SVG <path> data.
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"""
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gen = self.lexer.lex(text)
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next_val_fn = partial(next, *(gen,))
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token = next_val_fn()
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next_val_fn = gen.send
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token = next_val_fn(None)
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return self.rule_svg_path(next_val_fn, token)
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def rule_svg_path(self, next_val_fn, token):
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@ -171,12 +202,12 @@ class SVGPathParser(object):
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def rule_closepath(self, next_val_fn, token):
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command = token[1]
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token = next_val_fn()
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token = next_val_fn(None)
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return (command, []), token
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def rule_moveto_or_lineto(self, next_val_fn, token):
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command = token[1]
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token = next_val_fn()
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token = next_val_fn(None)
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coordinates = []
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while token[0] in self.number_tokens:
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pair, token = self.rule_coordinate_pair(next_val_fn, token)
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@ -185,7 +216,7 @@ class SVGPathParser(object):
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def rule_orthogonal_lineto(self, next_val_fn, token):
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command = token[1]
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token = next_val_fn()
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token = next_val_fn(None)
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coordinates = []
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while token[0] in self.number_tokens:
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coord, token = self.rule_coordinate(next_val_fn, token)
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@ -194,7 +225,7 @@ class SVGPathParser(object):
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def rule_curveto3(self, next_val_fn, token):
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command = token[1]
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token = next_val_fn()
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token = next_val_fn(None)
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coordinates = []
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while token[0] in self.number_tokens:
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pair1, token = self.rule_coordinate_pair(next_val_fn, token)
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@ -207,7 +238,7 @@ class SVGPathParser(object):
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def rule_curveto2(self, next_val_fn, token):
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command = token[1]
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token = next_val_fn()
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token = next_val_fn(None)
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coordinates = []
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while token[0] in self.number_tokens:
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pair1, token = self.rule_coordinate_pair(next_val_fn, token)
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@ -218,7 +249,7 @@ class SVGPathParser(object):
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def rule_curveto1(self, next_val_fn, token):
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command = token[1]
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token = next_val_fn()
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token = next_val_fn(None)
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coordinates = []
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while token[0] in self.number_tokens:
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pair1, token = self.rule_coordinate_pair(next_val_fn, token)
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@ -227,46 +258,46 @@ class SVGPathParser(object):
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def rule_elliptical_arc(self, next_val_fn, token):
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command = token[1]
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token = next_val_fn()
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token = next_val_fn(None)
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arguments = []
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while token[0] in self.number_tokens:
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rx = Decimal(token[1]) * 1
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if rx < Decimal("0.0"):
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raise SyntaxError("expecting a nonnegative number; got %r" % (token,))
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token = next_val_fn()
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token = next_val_fn(None)
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if token[0] not in self.number_tokens:
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raise SyntaxError("expecting a number; got %r" % (token,))
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ry = Decimal(token[1]) * 1
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if ry < Decimal("0.0"):
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raise SyntaxError("expecting a nonnegative number; got %r" % (token,))
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token = next_val_fn()
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token = next_val_fn(None)
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if token[0] not in self.number_tokens:
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raise SyntaxError("expecting a number; got %r" % (token,))
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axis_rotation = Decimal(token[1]) * 1
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token = next_val_fn()
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token = next_val_fn('flag')
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if token[1] not in ('0', '1'):
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raise SyntaxError("expecting a boolean flag; got %r" % (token,))
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large_arc_flag = Decimal(token[1]) * 1
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token = next_val_fn()
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token = next_val_fn('flag')
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if token[1] not in ('0', '1'):
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raise SyntaxError("expecting a boolean flag; got %r" % (token,))
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sweep_flag = Decimal(token[1]) * 1
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token = next_val_fn()
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token = next_val_fn(None)
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if token[0] not in self.number_tokens:
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raise SyntaxError("expecting a number; got %r" % (token,))
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x = Decimal(token[1]) * 1
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token = next_val_fn()
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token = next_val_fn(None)
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if token[0] not in self.number_tokens:
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raise SyntaxError("expecting a number; got %r" % (token,))
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y = Decimal(token[1]) * 1
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token = next_val_fn()
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token = next_val_fn(None)
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arguments.extend([rx, ry, axis_rotation, large_arc_flag, sweep_flag, x, y])
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return (command, arguments), token
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@ -275,7 +306,7 @@ class SVGPathParser(object):
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if token[0] not in self.number_tokens:
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raise SyntaxError("expecting a number; got %r" % (token,))
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x = getcontext().create_decimal(token[1])
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token = next_val_fn()
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token = next_val_fn(None)
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return x, token
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def rule_coordinate_pair(self, next_val_fn, token):
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@ -283,11 +314,11 @@ class SVGPathParser(object):
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if token[0] not in self.number_tokens:
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raise SyntaxError("expecting a number; got %r" % (token,))
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x = getcontext().create_decimal(token[1])
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token = next_val_fn()
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token = next_val_fn(None)
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if token[0] not in self.number_tokens:
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raise SyntaxError("expecting a number; got %r" % (token,))
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y = getcontext().create_decimal(token[1])
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token = next_val_fn()
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token = next_val_fn(None)
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return [x, y], token
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