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kll/funcparserlib/lexer.py

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# -*- coding: utf-8 -*-
# Copyright (c) 2008/2013 Andrey Vlasovskikh
#
# Permission is hereby granted, free of charge, to any person obtaining
# a copy of this software and associated documentation files (the
# "Software"), to deal in the Software without restriction, including
# without limitation the rights to use, copy, modify, merge, publish,
# distribute, sublicense, and/or sell copies of the Software, and to
# permit persons to whom the Software is furnished to do so, subject to
# the following conditions:
#
# The above copyright notice and this permission notice shall be included
# in all copies or substantial portions of the Software.
#
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
# EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
# MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
# IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
# CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
# TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
# SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
__all__ = ['make_tokenizer', 'Token', 'LexerError']
import re
class LexerError(Exception):
def __init__(self, place, msg):
self.place = place
self.msg = msg
def __str__(self):
s = u'cannot tokenize data'
line, pos = self.place
return u'%s: %d,%d: "%s"' % (s, line, pos, self.msg)
class Token(object):
def __init__(self, type, value, start=None, end=None):
self.type = type
self.value = value
self.start = start
self.end = end
def __repr__(self):
return u'Token(%r, %r)' % (self.type, self.value)
def __eq__(self, other):
# FIXME: Case sensitivity is assumed here
return self.type == other.type and self.value == other.value
def _pos_str(self):
if self.start is None or self.end is None:
return ''
else:
sl, sp = self.start
el, ep = self.end
return u'%d,%d-%d,%d:' % (sl, sp, el, ep)
def __str__(self):
s = u"%s %s '%s'" % (self._pos_str(), self.type, self.value)
return s.strip()
@property
def name(self):
return self.value
def pformat(self):
return u"%s %s '%s'" % (self._pos_str().ljust(20),
self.type.ljust(14),
self.value)
def make_tokenizer(specs):
"""[(str, (str, int?))] -> (str -> Iterable(Token))"""
def compile_spec(spec):
name, args = spec
return name, re.compile(*args)
compiled = [compile_spec(s) for s in specs]
def match_specs(specs, str, i, position):
line, pos = position
for type, regexp in specs:
m = regexp.match(str, i)
if m is not None:
value = m.group()
nls = value.count(u'\n')
n_line = line + nls
if nls == 0:
n_pos = pos + len(value)
else:
n_pos = len(value) - value.rfind(u'\n') - 1
return Token(type, value, (line, pos + 1), (n_line, n_pos))
else:
errline = str.splitlines()[line - 1]
raise LexerError((line, pos + 1), errline)
def f(str):
length = len(str)
line, pos = 1, 0
i = 0
while i < length:
t = match_specs(compiled, str, i, (line, pos))
yield t
line, pos = t.end
i += len(t.value)
return f
# This is an example of a token spec. See also [this article][1] for a
# discussion of searching for multiline comments using regexps (including `*?`).
#
# [1]: http://ostermiller.org/findcomment.html
_example_token_specs = [
('COMMENT', (r'\(\*(.|[\r\n])*?\*\)', re.MULTILINE)),
('COMMENT', (r'\{(.|[\r\n])*?\}', re.MULTILINE)),
('COMMENT', (r'//.*',)),
('NL', (r'[\r\n]+',)),
('SPACE', (r'[ \t\r\n]+',)),
('NAME', (r'[A-Za-z_][A-Za-z_0-9]*',)),
('REAL', (r'[0-9]+\.[0-9]*([Ee][+\-]?[0-9]+)*',)),
('INT', (r'[0-9]+',)),
('INT', (r'\$[0-9A-Fa-f]+',)),
('OP', (r'(\.\.)|(<>)|(<=)|(>=)|(:=)|[;,=\(\):\[\]\.+\-<>\*/@\^]',)),
('STRING', (r"'([^']|(''))*'",)),
('CHAR', (r'#[0-9]+',)),
('CHAR', (r'#\$[0-9A-Fa-f]+',)),
]
#tokenize = make_tokenizer(_example_token_specs)