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