# Copyright (C) 2009, 2010 Roman Zimbelmann <romanz@lavabit.com>
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program. If not, see <http://www.gnu.org/licenses/>.
class LazyParser(object):
"""Parse commands and extract information"""
def __init__(self, line):
self.line = line
self._chunks = None
self._rests = None
self._rests_loaded = 0
self._rests_gen_instance = None
try:
self.firstpart = line[:line.rindex(' ') + 1]
except ValueError:
self.firstpart = ''
def chunk(self, n, otherwise=''):
"""Chunks are pieces of the command seperated by spaces"""
if self._chunks is None:
self._chunks = self.line.split()
if len(self._chunks) > n:
return self._chunks[n]
else:
return otherwise
def rest(self, n, otherwise=''):
"""Rests are the strings which come after each word."""
if self._rests is None:
self._rests = list(self._rest_generator())
# TODO: Don't calculate all the rest elements if not needed
if len(self._rests) > n:
return self._rests[n]
else:
return otherwise
def _rest_generator(self):
lastrest = self.line
n = 0
while n < len(lastrest):
if lastrest[n] == ' ':
n += 1
else:
yield lastrest[n:]
n = lastrest.find(' ', n) + 1
if n <= 0:
break
lastrest = lastrest[n:]
n = 0
def __add__(self, newpart):
return self.firstpart + newpart