django通过ajax实现的在线计算器程序（界面精美）

# module pyparsing.py # # Copyright (c) 2003-2016 Paul T. McGuire # # 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. # __doc__ = \ """ pyparsing module - Classes and methods to define and execute parsing grammars The pyparsing module is an alternative approach to creating and executing simple grammars, vs. the traditional lex/yacc approach, or the use of regular expressions. With pyparsing, you don't need to learn a new syntax for defining grammars or matching expressions - the parsing module provides a library of classes that you use to construct the grammar directly in Python. Here is a program to parse "Hello, World!" (or any greeting of the form C{"<salutation>, <addressee>!"}), built up using L{Word}, L{Literal}, and L{And} elements (L{'+'<ParserElement.__add__>} operator gives L{And} expressions, strings are auto-converted to L{Literal} expressions):: from pyparsing import Word, alphas # define grammar of a greeting greet = Word(alphas) + "," + Word(alphas) + "!" hello = "Hello, World!" print (hello, "->", greet.parseString(hello)) The program outputs the following:: Hello, World! -> ['Hello', ',', 'World', '!'] The Python representation of the grammar is quite readable, owing to the self-explanatory class names, and the use of '+', '|' and '^' operators. The L{ParseResults} object returned from L{ParserElement.parseString<ParserElement.parseString>} can be accessed as a nested list, a dictionary, or an object with named attributes. The pyparsing module handles some of the problems that are typically vexing when writing text parsers: - extra or missing whitespace (the above program will also handle "Hello,World!", "Hello , World !", etc.) - quoted strings - embedded comments """ __version__ = "2.1.10" __versionTime__ = "07 Oct 2016 01:31 UTC" __author__ = "Paul McGuire <ptmcg@users.sourceforge.net>" import string from weakref import ref as wkref import copy import sys import warnings import re import sre_constants import collections import pprint import traceback import types from datetime import datetime try: from _thread import RLock except ImportError: from threading import RLock try: from collections import OrderedDict as _OrderedDict except ImportError: try: from ordereddict import OrderedDict as _OrderedDict except ImportError: _OrderedDict = None #~ sys.stderr.write( "testing pyparsing module, version %s, %s\n" % (__version__,__versionTime__ ) ) __all__ = [ 'And', 'CaselessKeyword', 'CaselessLiteral', 'CharsNotIn', 'Combine', 'Dict', 'Each', 'Empty', 'FollowedBy', 'Forward', 'GoToColumn', 'Group', 'Keyword', 'LineEnd', 'LineStart', 'Literal', 'MatchFirst', 'NoMatch', 'NotAny', 'OneOrMore', 'OnlyOnce', 'Optional', 'Or', 'ParseBaseException', 'ParseElementEnhance', 'ParseException', 'ParseExpression', 'ParseFatalException', 'ParseResults', 'ParseSyntaxException', 'ParserElement', 'QuotedString', 'RecursiveGrammarException', 'Regex', 'SkipTo', 'StringEnd', 'StringStart', 'Suppress', 'Token', 'TokenConverter', 'White', 'Word', 'WordEnd', 'WordStart', 'ZeroOrMore', 'alphanums', 'alphas', 'alphas8bit', 'anyCloseTag', 'anyOpenTag', 'cStyleComment', 'col', 'commaSeparatedList', 'commonHTMLEntity', 'countedArray', 'cppStyleComment', 'dblQuotedString', 'dblSlashComment', 'delimitedList', 'dictOf', 'downcaseTokens', 'empty', 'hexnums', 'htmlComment', 'javaStyleComment', 'line', 'lineEnd', 'lineStart', 'lineno', 'makeHTMLTags', 'makeXMLTags', 'matchOnlyAtCol', 'matchPreviousExpr', 'matchPreviousLiteral', 'nestedExpr', 'nullDebugAction', 'nums', 'oneOf', 'opAssoc', 'operatorPrecedence', 'printables', 'punc8bit', 'pythonStyleComment', 'quotedString', 'removeQuotes', 'replaceHTMLEntity', 'replaceWith', 'restOfLine', 'sglQuotedString', 'srange', 'stringEnd', 'stringStart', 'traceParseAction', 'unicodeString', 'upcaseTokens', 'withAttribute', 'indentedBlock', 'originalTextFor', 'ungroup', 'infixNotation','locatedExpr', 'withClass', 'CloseMatch', 'tokenMap', 'pyparsing_common', ] system_version = tuple(sys.version_info)[:3] PY_3 = system_version[0] == 3 if PY_3: _MAX_INT = sys.maxsize basestring = str unichr = chr _ustr = str # build list of single arg builtins, that can be used as parse actions singleArgBuiltins = [sum, len, sorted, reversed, list, tuple, set, any, all, min, max] else: _MAX_INT = sys.maxint range = xrange def _ustr(obj): """Drop-in replacement for str(obj) that tries to be Unicode friendly. It first tries str(obj). If that fails with a UnicodeEncodeError, then it tries unicode(obj). It then < returns the unicode object | encodes it with the default encoding | ... >. """ if isinstance(obj,unicode): return obj try: # If this works, then _ustr(obj) has the same behaviour as str(obj), so # it won't break any existing code. return str(obj) except UnicodeEncodeError: # Else encode it ret = unicode(obj).encode(sys.getdefaultencoding(), 'xmlcharrefreplace') xmlcharref = Regex('&#\d+;') xmlcharref.setParseAction(lambda t: '\\u' + hex(int(t[0][2:-1]))[2:]) return xmlcharref.transformString(ret) # build list of single arg builtins, tolerant of Python version, that can be used as parse actions singleArgBuiltins = [] import __builtin__ for fname in "sum len sorted reversed list tuple set any all min max".split(): try: singleArgBuiltins.append(getattr(__builtin__,fname)) except AttributeError: continue _generatorType = type((y for y in range(1))) def _xml_escape(data): """Escape &, <, >, ", ', etc. in a string of data.""" # ampersand must be replaced first from_symbols = '&><"\'' to_symbols = ('&'+s+';' for s in "amp gt lt quot apos".split()) for from_,to_ in zip(from_symbols, to_symbols): data = data.replace(from_, to_) return data class _Constants(object): pass alphas = string.ascii_uppercase + string.ascii_lowercase nums = "0123456789" hexnums = nums + "ABCDEFabcdef" alphanums = alphas + nums _bslash = chr(92) printables = "".join(c for c in string.printable if c not in string.whitespace) class ParseBaseException(Exception): """base exception class for all parsing runtime exceptions""" # Performance tuning: we construct a *lot* of these, so keep this # constructor as small and fast as possible def __init__( self, pstr, loc=0, msg=None, elem=None ): self.loc = loc if msg is None: self.msg = pstr self.pstr = "" else: self.msg = msg self.pstr = pstr self.pa