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100 lines
3.3 KiB
Python
100 lines
3.3 KiB
Python
from fontTools.voltLib.error import VoltLibError
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class Lexer(object):
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NUMBER = "NUMBER"
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STRING = "STRING"
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NAME = "NAME"
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NEWLINE = "NEWLINE"
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CHAR_WHITESPACE_ = " \t"
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CHAR_NEWLINE_ = "\r\n"
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CHAR_DIGIT_ = "0123456789"
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CHAR_UC_LETTER_ = "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
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CHAR_LC_LETTER_ = "abcdefghijklmnopqrstuvwxyz"
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CHAR_UNDERSCORE_ = "_"
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CHAR_PERIOD_ = "."
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CHAR_NAME_START_ = (
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CHAR_UC_LETTER_ + CHAR_LC_LETTER_ + CHAR_PERIOD_ + CHAR_UNDERSCORE_
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)
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CHAR_NAME_CONTINUATION_ = CHAR_NAME_START_ + CHAR_DIGIT_
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def __init__(self, text, filename):
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self.filename_ = filename
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self.line_ = 1
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self.pos_ = 0
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self.line_start_ = 0
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self.text_ = text
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self.text_length_ = len(text)
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def __iter__(self):
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return self
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def next(self): # Python 2
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return self.__next__()
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def __next__(self): # Python 3
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while True:
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token_type, token, location = self.next_()
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if token_type not in {Lexer.NEWLINE}:
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return (token_type, token, location)
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def location_(self):
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column = self.pos_ - self.line_start_ + 1
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return (self.filename_ or "<volt>", self.line_, column)
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def next_(self):
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self.scan_over_(Lexer.CHAR_WHITESPACE_)
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location = self.location_()
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start = self.pos_
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text = self.text_
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limit = len(text)
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if start >= limit:
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raise StopIteration()
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cur_char = text[start]
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next_char = text[start + 1] if start + 1 < limit else None
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if cur_char == "\n":
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self.pos_ += 1
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self.line_ += 1
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self.line_start_ = self.pos_
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return (Lexer.NEWLINE, None, location)
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if cur_char == "\r":
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self.pos_ += 2 if next_char == "\n" else 1
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self.line_ += 1
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self.line_start_ = self.pos_
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return (Lexer.NEWLINE, None, location)
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if cur_char == '"':
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self.pos_ += 1
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self.scan_until_('"\r\n')
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if self.pos_ < self.text_length_ and self.text_[self.pos_] == '"':
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self.pos_ += 1
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return (Lexer.STRING, text[start + 1 : self.pos_ - 1], location)
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else:
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raise VoltLibError("Expected '\"' to terminate string", location)
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if cur_char in Lexer.CHAR_NAME_START_:
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self.pos_ += 1
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self.scan_over_(Lexer.CHAR_NAME_CONTINUATION_)
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token = text[start : self.pos_]
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return (Lexer.NAME, token, location)
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if cur_char in Lexer.CHAR_DIGIT_:
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self.scan_over_(Lexer.CHAR_DIGIT_)
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return (Lexer.NUMBER, int(text[start : self.pos_], 10), location)
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if cur_char == "-" and next_char in Lexer.CHAR_DIGIT_:
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self.pos_ += 1
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self.scan_over_(Lexer.CHAR_DIGIT_)
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return (Lexer.NUMBER, int(text[start : self.pos_], 10), location)
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raise VoltLibError("Unexpected character: '%s'" % cur_char, location)
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def scan_over_(self, valid):
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p = self.pos_
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while p < self.text_length_ and self.text_[p] in valid:
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p += 1
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self.pos_ = p
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def scan_until_(self, stop_at):
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p = self.pos_
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while p < self.text_length_ and self.text_[p] not in stop_at:
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p += 1
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self.pos_ = p
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