100 lines
3.3 KiB
Python
100 lines
3.3 KiB
Python
from fontTools.voltLib.error import VoltLibError
|
|
|
|
|
|
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
|
|
|
|
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)
|
|
|
|
def location_(self):
|
|
column = self.pos_ - self.line_start_ + 1
|
|
return (self.filename_ or "<volt>", self.line_, column)
|
|
|
|
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)
|
|
|
|
def scan_over_(self, valid):
|
|
p = self.pos_
|
|
while p < self.text_length_ and self.text_[p] in valid:
|
|
p += 1
|
|
self.pos_ = p
|
|
|
|
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
|