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# module pyparsing.py # # Copyright (c) 2003-2006 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. # #from __future__ import generators __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 "<salutation>, <addressee>!"):: 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 parsed results returned from 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__ = "1.4.4-Mod-HaraldManske" __versionTime__ = "19 October 2006 23:11" __author__ = "Paul McGuire <ptmcg@users.sourceforge.net>" #Modified by Harald Manske: # - removed Deprication Warning of Upcase class # - created Downcase class import string import copy,sys import warnings import re import sre_constants import xml.sax.saxutils #~ sys.stderr.write( "testing pyparsing module, version %s, %s\n" % (__version__,__versionTime__ ) ) 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 | ... >. """ 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, e: # The Python docs (http://docs.python.org/ref/customization.html#l2h-182) # state that "The return value must be a string object". However, does a # unicode object (being a subclass of basestring) count as a "string # object"? # If so, then return a unicode object: return unicode(obj) # Else encode it... but how? There are many choices... :) # Replace unprintables with escape codes? #return unicode(obj).encode(sys.getdefaultencoding(), 'backslashreplace_errors') # Replace unprintables with question marks? #return unicode(obj).encode(sys.getdefaultencoding(), 'replace') # ... def _str2dict(strg): return dict( [(c,0) for c in strg] ) #~ return set( [c for c in strg] ) class _Constants(object): pass alphas = string.lowercase + string.uppercase nums = string.digits hexnums = nums + "ABCDEFabcdef" alphanums = alphas + nums class ParseBaseException(Exception): """base exception class for all parsing runtime exceptions""" __slots__ = ( "loc","msg","pstr","parserElement" ) # Performance tuning: we construct a *lot* of these, so keep this # constructor as small and fast as possible def __init__( self, pstr, loc, msg, elem=None ): self.loc = loc self.msg = msg self.pstr = pstr self.parserElement = elem def __getattr__( self, aname ): """supported attributes by name are: - lineno - returns the line number of the exception text - col - returns the column number of the exception text - line - returns the line containing the exception text """ if( aname == "lineno" ): return lineno( self.loc, self.pstr ) elif( aname in ("col", "column") ): return col( self.loc, self.pstr ) elif( aname == "line" ): return line( self.loc, self.pstr ) else: raise AttributeError, aname def __str__( self ): return "%s (at char %d), (line:%d, col:%d)" % ( self.msg, self.loc, self.lineno, self.column ) def __repr__( self ): return _ustr(self) def markInputline( self, markerString = ">!<" ): """Extracts the exception line from the input string, and marks the location of the exception with a special symbol. """ line_str = self.line line_column = self.column - 1 if markerString: line_str = "".join( [line_str[:line_column], markerString, line_str[line_column:]]) return line_str.strip() class ParseException(ParseBaseException): """exception thrown when parse expressions don't match class""" """supported attributes by name are: - lineno - returns the line number of the exception text - col - returns the column number of the exception text - line - returns the line containing the exception text """ pass class ParseFatalException(ParseBaseException): """user-throwable exception thrown when inconsistent parse content is found; stops all parsing immediately""" pass class ReparseException(ParseBaseException): def __init_( self, newstring, restartLoc ): self.newParseText = newstring self.reparseLoc = restartLoc class RecursiveGrammarException(Exception): """exception thrown by validate() if the grammar could be improperly recursive""" def __init__( self, parseElementList ): self.parseElementTrace = parseElementList def __str__( self ): return "RecursiveGrammarException: %s" % self.parseElementTrace class ParseResults(object): """Structured parse results, to provide multiple means of access to the parsed data: - as a list (len(results)) - by list index (results[0], results[1], etc.) - by attribute (results.<resultsName>) """ __slots__ = ( "__toklist", "__tokdict", "__doinit", "__name", "__parent", "__accumNames" ) def __new__(cls, toklist, name=None, asList=True, modal=True ): if isinstance(toklist, cls): return toklist retobj = object.__new__(cls) retobj.__doinit = True return retobj # Performance tuning: we construct a *lot* of these, so keep this # constructor as small and fast as possible def __init__( self, toklist, name=None, asList=True, modal=True ): if self.__doinit: self.__doinit = False self.__name = None self.__parent = None self.__accumNames = {} if isinstance(toklist, list): self.__toklist = toklist[:] else: self.__toklist = [toklist] self.__tokdict = dict() # this line is related to debugging the asXML bug #~ asList = False if name: if not modal: self.__accumNames[name] = 0 if isinstance(name,int): name = _ustr(name) # will always return a str, but use _ustr for consistency self.__name = name if not toklist in (None,'',[]): if isinstance(toklist,basestring): toklist = [ toklist ] if asList: if isinstance(toklist,ParseResults): self[name] = (toklist.copy(),-1) else: self[name] = (ParseResults(toklist[0]),-1) self[name].__name = name else: try: self[name] = toklist[0] except (KeyError,TypeError): self[name] = toklist def __getitem__( self, i ): if isinstance( i, (int,slice) ): return self.__toklist[i] else: if i not in self.__accumNames: return self.__tokdict[i][-1][0] else: return ParseResults([ v[0] for v in self.__tokdict[i] ]) def __setitem__( self, k, v ): if isinstance(v,tuple): self.__tokdict[k] = self.__tokdict.get(k,list()) + [v] sub = v[0] elif isinstance(k,int): self.__toklist[k] = v sub = v else: self.__tokdict[k] = self.__tokdict.get(k,list()) + [(v,0)] sub = v if isinstance(sub,ParseResults): sub.__parent = self def __delitem__( self, i ): if isinstance(i,(int,slice)): del self.__toklist[i] else: del self._tokdict[i] def __contains__( self, k ): return self.__tokdict.has_key(k) def __len__( self ): return len( self.__toklist ) def __nonzero__( self ): return len( self.__toklist ) > 0 def __iter__( self ): return iter( self.__toklist ) def keys( self ): """Returns all named result keys.""" return self.__tokdict.keys() def items( self ): """Returns all named result keys and values as a list of tuples.""" return [(k,self[k]) for k in self.__tokdict.keys()] def values( self ): """Returns all named result values.""" return [ v[-1][0] for v in self.__tokdict.values() ] def __getattr__( self, name ): if name not in self.__slots__: if self.__tokdict.has_key( name ): if name not in self.__accumNames: return self.__tokdict[name][-1][0] else: return ParseResults([ v[0] for v in self.__tokdict[name] ]) else: return "" return None def __add__( self, other ): ret = self.copy() ret += other return ret def __iadd__( self, other ): if other.__tokdict: offset = len(self.__toklist) addoffset = ( lambda a: (a<0 and offset) or (a+offset) ) otheritems = other.__tokdict.items() otherdictitems = [(k,(v[0],addoffset(v[1])) ) for (k,vlist) in otheritems for v in vlist] for k,v in otherdictitems: self[k] = v if isinstance(v[0],ParseResults): v[0].__parent = self self.__toklist += other.__toklist self.__accumNames.update( other.__accumNames ) del other return self def __repr__( self ): return "(%s, %s)" % ( repr( self.__toklist ), repr( self.__tokdict ) ) def __str__( self ): out = "[" sep = "" for i in self.__toklist: if isinstance(i, ParseResults): out += sep + _ustr(i) else: out += sep + repr(i) sep = ", " out += "]" return out def _asStringList( self, sep='' ): out = [] for item in self.__toklist: if out and sep: out.append(sep) if isinstance( item, ParseResults ): out += item._asStringList() else: out.append( _ustr(item) ) return out def asList( self ): """Returns the parse results as a nested list of matching tokens, all converted to strings.""" out = [] for res in self.__toklist: if isinstance(res,ParseResults): out.append( res.asList() ) else: out.append( res ) return out def asDict( self ): """Returns the named parse results as dictionary.""" return dict( self.items() ) def copy( self ): """Returns a new copy of a ParseResults object.""" ret = ParseResults( self.__toklist ) ret.__tokdict = self.__tokdict.copy() ret.__parent = self.__parent ret.__accumNames.update( self.__accumNames ) ret.__name = self.__name return ret def asXML( self, doctag=None, namedItemsOnly=False, indent="", formatted=True ): """Returns the parse results as XML. Tags are created for tokens and lists that have defined results names.""" nl = "\n" out = [] namedItems = dict( [ (v[1],k) for (k,vlist) in self.__tokdict.items() for v in vlist ] ) nextLevelIndent = indent + " " # collapse out indents if formatting is not desired if not formatted: indent = "" nextLevelIndent = "" nl = "" selfTag = None if doctag is not None: selfTag = doctag else: if self.__name: selfTag = self.__name if not selfTag: if namedItemsOnly: return "" else: selfTag = "ITEM" out += [ nl, indent, "<", selfTag, ">" ] worklist = self.__toklist for i,res in enumerate(worklist): if isinstance(res,ParseResults): if i in namedItems: out += [ res.asXML(namedItems[i], namedItemsOnly and doctag is None, nextLevelIndent,formatted)] else: out += [ res.asXML(None, namedItemsOnly and doctag is None, nextLevelIndent,formatted)] else: # individual token, see if there is a name for it resTag = None if i in namedItems: resTag = namedItems[i] if not resTag: if namedItemsOnly: continue else: resTag = "ITEM" xmlBodyText = xml.sax.saxutils.escape(_ustr(res)) out += [ nl, nextLevelIndent, "<", resTag, ">", xmlBodyText, "</", resTag, ">" ] out += [ nl, indent, "</", selfTag, ">" ] return "".join(out) def __lookup(self,sub): for k,vlist in self.__tokdict.items(): for v,loc in vlist: if sub is v: return k return None def getName(self): """Returns the results name for this token expression.""" if self.__name: return self.__name elif self.__parent: par = self.__parent if par: return par.__lookup(self) else: return None elif (len(self) == 1 and len(self.__tokdict) == 1 and self.__tokdict.values()[0][0][1] in (0,-1)): return self.__tokdict.keys()[0] else: return None def dump(self,indent='',depth=0): """Diagnostic method for listing out the contents of a ParseResults. Accepts an optional indent argument so that this string can be embedded in a nested display of other data.""" out = [] out.append( indent+str(self.asList()) ) keys = self.items() keys.sort() for k,v in keys: if out: out.append('\n') out.append( "%s%s- %s: " % (indent,(' '*depth), k) ) if isinstance(v,ParseResults): if v.keys(): #~ out.append('\n') out.append( v.dump(indent,depth+1) ) #~ out.append('\n') else: out.append(str(v)) else: out.append(str(v)) #~ out.append('\n') return "".join(out) def col (loc,strg): """Returns current column within a string, counting newlines as line separators. The first column is number 1. """ return (loc<len(strg) and strg[loc] == '\n') and 1 or loc - strg.rfind("\n", 0, loc) def lineno(loc,strg): """Returns current line number within a string, counting newlines as line separators. The first line is number 1. """ return strg.count("\n",0,loc) + 1 def line( loc, strg ): """Returns the line of text containing loc within a string, counting newlines as line separators. """ lastCR = strg.rfind("\n", 0, loc) nextCR = strg.find("\n", loc) if nextCR > 0: return strg[lastCR+1:nextCR] else: return strg[lastCR+1:] def _defaultStartDebugAction( instring, loc, expr ): print "Match",expr,"at loc",loc,"(%d,%d)" % ( lineno(loc,instring), col(loc,instring) ) def _defaultSuccessDebugAction( instring, startloc, endloc, expr, toks ): print "Matched",expr,"->",toks.asList() def _defaultExceptionDebugAction( instring, loc, expr, exc ): print "Exception raised:", exc def nullDebugAction(*args): """'Do-nothing' debug action, to suppress debugging output during parsing.""" pass class ParserElement(object): """Abstract base level parser element class.""" DEFAULT_WHITE_CHARS = " \n\t\r" def setDefaultWhitespaceChars( chars ): """Overrides the default whitespace chars """ ParserElement.DEFAULT_WHITE_CHARS = chars setDefaultWhitespaceChars = staticmethod(setDefaultWhitespaceChars) def __init__( self, savelist=False ): self.parseAction = list() self.failAction = None #~ self.name = "<unknown>" # don't define self.name, let subclasses try/except upcall self.strRepr = None self.resultsName = None self.saveAsList = savelist self.skipWhitespace = True self.whiteChars = ParserElement.DEFAULT_WHITE_CHARS self.copyDefaultWhiteChars = True self.mayReturnEmpty = False self.keepTabs = False self.ignoreExprs = list() self.debug = False self.streamlined = False self.mayIndexError = True self.errmsg = "" self.modalResults = True self.debugActions = ( None, None, None ) self.re = None def copy( self ): """Make a copy of this ParserElement. Useful for defining different parse actions for the same parsing pattern, using copies of the original parse element.""" cpy = copy.copy( self ) cpy.parseAction = self.parseAction[:] cpy.ignoreExprs = self.ignoreExprs[:] if self.copyDefaultWhiteChars: cpy.whiteChars = ParserElement.DEFAULT_WHITE_CHARS return cpy def setName( self, name ): """Define name for this expression, for use in debugging.""" self.name = name self.errmsg = "Expected " + self.name return self def setResultsName( self, name, listAllMatches=False ): """Define name for referencing matching tokens as a nested attribute of the returned parse results. NOTE: this returns a *copy* of the original ParserElement object; this is so that the client can define a basic element, such as an integer, and reference it in multiple places with different names. """ newself = self.copy() newself.resultsName = name newself.modalResults = not listAllMatches return newself def normalizeParseActionArgs( f ): """Internal method used to decorate parse actions that take fewer than 3 arguments, so that all parse actions can be called as f(s,l,t).""" STAR_ARGS = 4 try: restore = None if isinstance(f,type): restore = f f = f.__init__ if f.func_code.co_flags & STAR_ARGS: return f numargs = f.func_code.co_argcount if hasattr(f,"im_self"): numargs -= 1 if restore: f = restore except AttributeError: try: # not a function, must be a callable object, get info from the # im_func binding of its bound __call__ method if f.__call__.im_func.func_code.co_flags & STAR_ARGS: return f numargs = f.__call__.im_func.func_code.co_argcount if hasattr(f.__call__,"im_self"): numargs -= 1 except AttributeError: # not a bound method, get info directly from __call__ method if f.__call__.func_code.co_flags & STAR_ARGS: return f numargs = f.__call__.func_code.co_argcount if hasattr(f.__call__,"im_self"): numargs -= 1 #~ print "adding function %s with %d args" % (f.func_name,numargs) if numargs == 3: return f else: if numargs == 2: def tmp(s,l,t): return f(l,t) elif numargs == 1: def tmp(s,l,t): return f(t) else: #~ numargs == 0: def tmp(s,l,t): return f() return tmp normalizeParseActionArgs = staticmethod(normalizeParseActionArgs) def setParseAction( self, *fns ): """Define action to perform when successfully matching parse element definition. Parse action fn is a callable method with 0-3 arguments, called as fn(s,loc,toks), fn(loc,toks), fn(toks), or just fn(), where: - s = the original string being parsed - loc = the location of the matching substring - toks = a list of the matched tokens, packaged as a ParseResults object If the functions in fns modify the tokens, they can return them as the return value from fn, and the modified list of tokens will replace the original. Otherwise, fn does not need to return any value.""" self.parseAction = map(self.normalizeParseActionArgs, list(fns)) return self def addParseAction( self, *fns ): """Add parse action to expression's list of parse actions. See setParseAction_.""" self.parseAction += map(self.normalizeParseActionArgs, list(fns)) return self def setFailAction( self, fn ): """Define action to perform if parsing fails at this expression. Fail acton fn is a callable function that takes the arguments fn(s,loc,expr,err) where: - s = string being parsed - loc = location where expression match was attempted and failed - expr = the parse expression that failed - err = the exception thrown The function returns no value. It may throw ParseFatalException if it is desired to stop parsing immediately.""" self.failAction = fn return self def skipIgnorables( self, instring, loc ): exprsFound = True while exprsFound: exprsFound = False for e in self.ignoreExprs: try: while 1: loc,dummy = e._parse( instring, loc ) exprsFound = True except ParseException: pass return loc def preParse( self, instring, loc ): if self.ignoreExprs: loc = self.skipIgnorables( instring, loc ) if self.skipWhitespace: wt = self.whiteChars instrlen = len(instring) while loc < instrlen and instring[loc] in wt: loc += 1 return loc def parseImpl( self, instring, loc, doActions=True ): return loc, [] def postParse( self, instring, loc, tokenlist ): return tokenlist #~ @profile def _parseNoCache( self, instring, loc, doActions=True, callPreParse=True ): debugging = ( self.debug ) #and doActions ) if debugging or self.failAction: #~ print "Match",self,"at loc",loc,"(%d,%d)" % ( lineno(loc,instring), col(loc,instring) ) if (self.debugActions[0] ): self.debugActions[0]( instring, loc, self ) if callPreParse: preloc = self.preParse( instring, loc ) else: preloc = loc tokensStart = loc try: try: loc,tokens = self.parseImpl( instring, preloc, doActions ) except IndexError: raise ParseException( instring, len(instring), self.errmsg, self ) #~ except ReparseException, retryEx: #~ pass except ParseException, err: #~ print "Exception raised:", err if self.debugActions[2]: self.debugActions[2]( instring, tokensStart, self, err ) if self.failAction: self.failAction( instring, tokensStart, self, err ) raise else: if callPreParse: preloc = self.preParse( instring, loc ) else: preloc = loc tokensStart = loc if self.mayIndexError or loc >= len(instring): try: loc,tokens = self.parseImpl( instring, preloc, doActions ) except IndexError: raise ParseException( instring, len(instring), self.errmsg, self ) else: loc,tokens = self.parseImpl( instring, preloc, doActions ) tokens = self.postParse( instring, loc, tokens ) retTokens = ParseResults( tokens, self.resultsName, asList=self.saveAsList, modal=self.modalResults ) if self.parseAction and doActions: if debugging: try: for fn in self.parseAction: tokens = fn( instring, tokensStart, retTokens ) if tokens is not None: retTokens = ParseResults( tokens, self.resultsName, asList=self.saveAsList and isinstance(tokens,(ParseResults,list)), modal=self.modalResults ) except ParseException, err: #~ print "Exception raised in user parse action:", err if (self.debugActions[2] ): self.debugActions[2]( instring, tokensStart, self, err ) raise else: for fn in self.parseAction: tokens = fn( instring, tokensStart, retTokens ) if tokens is not None: retTokens = ParseResults( tokens, self.resultsName, asList=self.saveAsList and isinstance(tokens,(ParseResults,list)), modal=self.modalResults ) if debugging: #~ print "Matched",self,"->",retTokens.asList() if (self.debugActions[1] ): self.debugActions[1]( instring, tokensStart, loc, self, retTokens ) return loc, retTokens def tryParse( self, instring, loc ): return self._parse( instring, loc, doActions=False )[0] # this method gets repeatedly called during backtracking with the same arguments - # we can cache these arguments and save ourselves the trouble of re-parsing the contained expression def _parseCache( self, instring, loc, doActions=True, callPreParse=True ): if doActions and self.parseAction: return self._parseNoCache( instring, loc, doActions, callPreParse ) lookup = (self,instring,loc,callPreParse) if lookup in ParserElement._exprArgCache: value = ParserElement._exprArgCache[ lookup ] if isinstance(value,Exception): if isinstance(value,ParseBaseException): value.loc = loc raise value return value else: try: ParserElement._exprArgCache[ lookup ] = \ value = self._parseNoCache( instring, loc, doActions, callPreParse ) return value except ParseBaseException, pe: ParserElement._exprArgCache[ lookup ] = pe raise _parse = _parseNoCache # argument cache for optimizing repeated calls when backtracking through recursive expressions _exprArgCache = {} def resetCache(): ParserElement._exprArgCache.clear() resetCache = staticmethod(resetCache) _packratEnabled = False def enablePackrat(): """Enables "packrat" parsing, which adds memoizing to the parsing logic. Repeated parse attempts at the same string location (which happens often in many complex grammars) can immediately return a cached value, instead of re-executing parsing/validating code. Memoizing is done of both valid results and parsing exceptions. This speedup may break existing programs that use parse actions that have side-effects. For this reason, packrat parsing is disabled when you first import pyparsing. To activate the packrat feature, your program must call the class method ParserElement.enablePackrat(). If your program uses psyco to "compile as you go", you must call enablePackrat before calling psyco.full(). If you do not do this, Python will crash. For best results, call enablePackrat() immediately after importing pyparsing. """ if not ParserElement._packratEnabled: ParserElement._packratEnabled = True ParserElement._parse = ParserElement._parseCache enablePackrat = staticmethod(enablePackrat) def parseString( self, instring ): """Execute the parse expression with the given string. This is the main interface to the client code, once the complete expression has been built. """ ParserElement.resetCache() if not self.streamlined: self.streamline() #~ self.saveAsList = True for e in self.ignoreExprs: e.streamline() if self.keepTabs: loc, tokens = self._parse( instring, 0 ) else: loc, tokens = self._parse( instring.expandtabs(), 0 ) return tokens def scanString( self, instring, maxMatches=sys.maxint ): """Scan the input string for expression matches. Each match will return the matching tokens, start location, and end location. May be called with optional maxMatches argument, to clip scanning after 'n' matches are found.""" if not self.streamlined: self.streamline() for e in self.ignoreExprs: e.streamline() if not self.keepTabs: instring = instring.expandtabs() instrlen = len(instring) loc = 0 preparseFn = self.preParse parseFn = self._parse ParserElement.resetCache() matches = 0 while loc <= instrlen and matches < maxMatches: try: preloc = preparseFn( instring, loc ) nextLoc,tokens = parseFn( instring, preloc, callPreParse=False ) except ParseException: loc = preloc+1 else: matches += 1 yield tokens, preloc, nextLoc loc = nextLoc def transformString( self, instring ): """Extension to scanString, to modify matching text with modified tokens that may be returned from a parse action. To use transformString, define a grammar and attach a parse action to it that modifies the returned token list. Invoking transformString() on a target string will then scan for matches, and replace the matched text patterns according to the logic in the parse action. transformString() returns the resulting transformed string.""" out = [] lastE = 0 # force preservation of <TAB>s, to minimize unwanted transformation of string, and to # keep string locs straight between transformString and scanString self.keepTabs = True for t,s,e in self.scanString( instring ): out.append( instring[lastE:s] ) if t: if isinstance(t,ParseResults): out += t.asList() elif isinstance(t,list): out += t else: out.append(t) lastE = e out.append(instring[lastE:]) return "".join(out) def searchString( self, instring, maxMatches=sys.maxint ): """Another extension to scanString, simplifying the access to the tokens found to match the given parse expression. May be called with optional maxMatches argument, to clip searching after 'n' matches are found. """ return ParseResults([ t for t,s,e in self.scanString( instring, maxMatches ) ]) def __add__(self, other ): """Implementation of + operator - returns And""" if isinstance( other, basestring ): other = Literal( other ) if not isinstance( other, ParserElement ): warnings.warn("Cannot add element of type %s to ParserElement" % type(other), SyntaxWarning, stacklevel=2) return And( [ self, other ] ) def __radd__(self, other ): """Implementation of += operator""" if isinstance( other, basestring ): other = Literal( other ) if not isinstance( other, ParserElement ): warnings.warn("Cannot add element of type %s to ParserElement" % type(other), SyntaxWarning, stacklevel=2) return other + self def __or__(self, other ): """Implementation of | operator - returns MatchFirst""" if isinstance( other, basestring ): other = Literal( other ) if not isinstance( other, ParserElement ): warnings.warn("Cannot add element of type %s to ParserElement" % type(other), SyntaxWarning, stacklevel=2) return MatchFirst( [ self, other ] ) def __ror__(self, other ): """Implementation of |= operator""" if isinstance( other, basestring ): other = Literal( other ) if not isinstance( other, ParserElement ): warnings.warn("Cannot add element of type %s to ParserElement" % type(other), SyntaxWarning, stacklevel=2) return other | self def __xor__(self, other ): """Implementation of ^ operator - returns Or""" if isinstance( other, basestring ): other = Literal( other ) if not isinstance( other, ParserElement ): warnings.warn("Cannot add element of type %s to ParserElement" % type(other), SyntaxWarning, stacklevel=2) return Or( [ self, other ] ) def __rxor__(self, other ): """Implementation of ^= operator""" if isinstance( other, basestring ): other = Literal( other ) if not isinstance( other, ParserElement ): warnings.warn("Cannot add element of type %s to ParserElement" % type(other), SyntaxWarning, stacklevel=2) return other ^ self def __and__(self, other ): """Implementation of & operator - returns Each""" if isinstance( other, basestring ): other = Literal( other ) if not isinstance( other, ParserElement ): warnings.warn("Cannot add element of type %s to ParserElement" % type(other), SyntaxWarning, stacklevel=2) return Each( [ self, other ] ) def __rand__(self, other ): """Implementation of right-& operator""" if isinstance( other, basestring ): other = Literal( other ) if not isinstance( other, ParserElement ): warnings.warn("Cannot add element of type %s to ParserElement" % type(other), SyntaxWarning, stacklevel=2) return other & self def __invert__( self ): """Implementation of ~ operator - returns NotAny""" return NotAny( self ) def suppress( self ): """Suppresses the output of this ParserElement; useful to keep punctuation from cluttering up returned output. """ return Suppress( self ) def leaveWhitespace( self ): """Disables the skipping of whitespace before matching the characters in the ParserElement's defined pattern. This is normally only used internally by the pyparsing module, but may be needed in some whitespace-sensitive grammars. """ self.skipWhitespace = False return self def setWhitespaceChars( self, chars ): """Overrides the default whitespace chars """ self.skipWhitespace = True self.whiteChars = chars self.copyDefaultWhiteChars = False return self def parseWithTabs( self ): """Overrides default behavior to expand <TAB>s to spaces before parsing the input string. Must be called before parseString when the input grammar contains elements that match <TAB> characters.""" self.keepTabs = True return self def ignore( self, other ): """Define expression to be ignored (e.g., comments) while doing pattern matching; may be called repeatedly, to define multiple comment or other ignorable patterns. """ if isinstance( other, Suppress ): if other not in self.ignoreExprs: self.ignoreExprs.append( other ) else: self.ignoreExprs.append( Suppress( other ) ) return self def setDebugActions( self, startAction, successAction, exceptionAction ): """Enable display of debugging messages while doing pattern matching.""" self.debugActions = (startAction or _defaultStartDebugAction, successAction or _defaultSuccessDebugAction, exceptionAction or _defaultExceptionDebugAction) self.debug = True return self def setDebug( self, flag=True ): """Enable display of debugging messages while doing pattern matching.""" if flag: self.setDebugActions( _defaultStartDebugAction, _defaultSuccessDebugAction, _defaultExceptionDebugAction ) else: self.debug = False return self def __str__( self ): return self.name def __repr__( self ): return _ustr(self) def streamline( self ): self.streamlined = True self.strRepr = None return self def checkRecursion( self, parseElementList ): pass def validate( self, validateTrace=[] ): """Check defined expressions for valid structure, check for infinite recursive definitions.""" self.checkRecursion( [] ) def parseFile( self, file_or_filename ): """Execute the parse expression on the given file or filename. If a filename is specified (instead of a file object), the entire file is opened, read, and closed before parsing. """ try: file_contents = file_or_filename.read() except AttributeError: f = open(file_or_filename, "rb") file_contents = f.read() f.close() return self.parseString(file_contents) class Token(ParserElement): """Abstract ParserElement subclass, for defining atomic matching patterns.""" def __init__( self ): super(Token,self).__init__( savelist=False ) self.myException = ParseException("",0,"",self) def setName(self, name): s = super(Token,self).setName(name) self.errmsg = "Expected " + self.name s.myException.msg = self.errmsg return s class Empty(Token): """An empty token, will always match.""" def __init__( self ): super(Empty,self).__init__() self.name = "Empty" self.mayReturnEmpty = True self.mayIndexError = False class NoMatch(Token): """A token that will never match.""" def __init__( self ): super(NoMatch,self).__init__() self.name = "NoMatch" self.mayReturnEmpty = True self.mayIndexError = False self.errmsg = "Unmatchable token" self.myException.msg = self.errmsg def parseImpl( self, instring, loc, doActions=True ): exc = self.myException exc.loc = loc exc.pstr = instring raise exc class Literal(Token): """Token to exactly match a specified string.""" def __init__( self, matchString ): super(Literal,self).__init__() self.match = matchString self.matchLen = len(matchString) try: self.firstMatchChar = matchString[0] except IndexError: warnings.warn("null string passed to Literal; use Empty() instead", SyntaxWarning, stacklevel=2) self.__class__ = Empty self.name = '"%s"' % self.match self.errmsg = "Expected " + self.name self.mayReturnEmpty = False self.myException.msg = self.errmsg self.mayIndexError = False # Performance tuning: this routine gets called a *lot* # if this is a single character match string and the first character matches, # short-circuit as quickly as possible, and avoid calling startswith #~ @profile def parseImpl( self, instring, loc, doActions=True ): if (instring[loc] == self.firstMatchChar and (self.matchLen==1 or instring.startswith(self.match,loc)) ): return loc+self.matchLen, self.match #~ raise ParseException( instring, loc, self.errmsg ) exc = self.myException exc.loc = loc exc.pstr = instring raise exc class Keyword(Token): """Token to exactly match a specified string as a keyword, that is, it must be immediately followed by a non-keyword character. Compare with Literal:: Literal("if") will match the leading 'if' in 'ifAndOnlyIf'. Keyword("if") will not; it will only match the leading 'if in 'if x=1', or 'if(y==2)' Accepts two optional constructor arguments in addition to the keyword string: identChars is a string of characters that would be valid identifier characters, defaulting to all alphanumerics + "_" and "$"; caseless allows case-insensitive matching, default is False. """ DEFAULT_KEYWORD_CHARS = alphanums+"_$" def __init__( self, matchString, identChars=DEFAULT_KEYWORD_CHARS, caseless=False ): super(Keyword,self).__init__() self.match = matchString self.matchLen = len(matchString) try: self.firstMatchChar = matchString[0] except IndexError: warnings.warn("null string passed to Keyword; use Empty() instead", SyntaxWarning, stacklevel=2) self.name = '"%s"' % self.match self.errmsg = "Expected " + self.name self.mayReturnEmpty = False self.myException.msg = self.errmsg self.mayIndexError = False self.caseless = caseless if caseless: self.caselessmatch = matchString.upper() identChars = identChars.upper() self.identChars = _str2dict(identChars) def parseImpl( self, instring, loc, doActions=True ): if self.caseless: if ( (instring[ loc:loc+self.matchLen ].upper() == self.caselessmatch) and (loc >= len(instring)-self.matchLen or instring[loc+self.matchLen].upper() not in self.identChars) and (loc == 0 or instring[loc-1].upper() not in self.identChars) ): return loc+self.matchLen, self.match else: if (instring[loc] == self.firstMatchChar and (self.matchLen==1 or instring.startswith(self.match,loc)) and (loc >= len(instring)-self.matchLen or instring[loc+self.matchLen] not in self.identChars) and (loc == 0 or instring[loc-1] not in self.identChars) ): return loc+self.matchLen, self.match #~ raise ParseException( instring, loc, self.errmsg ) exc = self.myException exc.loc = loc exc.pstr = instring raise exc def copy(self): c = super(Keyword,self).copy() c.identChars = Keyword.DEFAULT_KEYWORD_CHARS return c def setDefaultKeywordChars( chars ): """Overrides the default Keyword chars """ Keyword.DEFAULT_KEYWORD_CHARS = chars setDefaultKeywordChars = staticmethod(setDefaultKeywordChars) class CaselessLiteral(Literal): """Token to match a specified string, ignoring case of letters. Note: the matched results will always be in the case of the given match string, NOT the case of the input text. """ def __init__( self, matchString ): super(CaselessLiteral,self).__init__( matchString.upper() ) # Preserve the defining literal. self.returnString = matchString self.name = "'%s'" % self.returnString self.errmsg = "Expected " + self.name self.myException.msg = self.errmsg def parseImpl( self, instring, loc, doActions=True ): if instring[ loc:loc+self.matchLen ].upper() == self.match: return loc+self.matchLen, self.returnString #~ raise ParseException( instring, loc, self.errmsg ) exc = self.myException exc.loc = loc exc.pstr = instring raise exc class CaselessKeyword(Keyword): def __init__( self, matchString, identChars=Keyword.DEFAULT_KEYWORD_CHARS ): super(CaselessKeyword,self).__init__( matchString, identChars, caseless=True ) def parseImpl( self, instring, loc, doActions=True ): if ( (instring[ loc:loc+self.matchLen ].upper() == self.caselessmatch) and (loc >= len(instring)-self.matchLen or instring[loc+self.matchLen].upper() not in self.identChars) ): return loc+self.matchLen, self.match #~ raise ParseException( instring, loc, self.errmsg ) exc = self.myException exc.loc = loc exc.pstr = instring raise exc class Word(Token): """Token for matching words composed of allowed character sets. Defined with string containing all allowed initial characters, an optional string containing allowed body characters (if omitted, defaults to the initial character set), and an optional minimum, maximum, and/or exact length. """ def __init__( self, initChars, bodyChars=None, min=1, max=0, exact=0 ): super(Word,self).__init__() self.initCharsOrig = initChars self.initChars = _str2dict(initChars) if bodyChars : self.bodyCharsOrig = bodyChars self.bodyChars = _str2dict(bodyChars) else: self.bodyCharsOrig = initChars self.bodyChars = _str2dict(initChars) self.maxSpecified = max > 0 self.minLen = min if max > 0: self.maxLen = max else: self.maxLen = sys.maxint if exact > 0: self.maxLen = exact self.minLen = exact self.name = _ustr(self) self.errmsg = "Expected " + self.name self.myException.msg = self.errmsg self.mayIndexError = False if ' ' not in self.initCharsOrig+self.bodyCharsOrig and (min==1 and max==0 and exact==0): if self.bodyCharsOrig == self.initCharsOrig: self.reString = "[%s]+" % _escapeRegexRangeChars(self.initCharsOrig) elif len(self.bodyCharsOrig) == 1: self.reString = "%s[%s]*" % \ (re.escape(self.initCharsOrig), _escapeRegexRangeChars(self.bodyCharsOrig),) else: self.reString = "[%s][%s]*" % \ (_escapeRegexRangeChars(self.initCharsOrig), _escapeRegexRangeChars(self.bodyCharsOrig),) try: self.re = re.compile( self.reString ) except: self.re = None def parseImpl( self, instring, loc, doActions=True ): if self.re: result = self.re.match(instring,loc) if not result: exc = self.myException exc.loc = loc exc.pstr = instring raise exc loc = result.end() return loc,result.group() if not(instring[ loc ] in self.initChars): #~ raise ParseException( instring, loc, self.errmsg ) exc = self.myException exc.loc = loc exc.pstr = instring raise exc start = loc loc += 1 instrlen = len(instring) bodychars = self.bodyChars maxloc = start + self.maxLen maxloc = min( maxloc, instrlen ) while loc < maxloc and instring[loc] in bodychars: loc += 1 throwException = False if loc - start < self.minLen: throwException = True if self.maxSpecified and loc < instrlen and instring[loc] in bodychars: throwException = True if throwException: #~ raise ParseException( instring, loc, self.errmsg ) exc = self.myException exc.loc = loc exc.pstr = instring raise exc return loc, instring[start:loc] def __str__( self ): try: return super(Word,self).__str__() except: pass if self.strRepr is None: def charsAsStr(s): if len(s)>4: return s[:4]+"..." else: return s if ( self.initCharsOrig != self.bodyCharsOrig ): self.strRepr = "W:(%s,%s)" % ( charsAsStr(self.initCharsOrig), charsAsStr(self.bodyCharsOrig) ) else: self.strRepr = "W:(%s)" % charsAsStr(self.initCharsOrig) return self.strRepr class Regex(Token): """Token for matching strings that match a given regular expression. Defined with string specifying the regular expression in a form recognized by the inbuilt Python re module. """ def __init__( self, pattern, flags=0): """The parameters pattern and flags are passed to the re.compile() function as-is. See the Python re module for an explanation of the acceptable patterns and flags.""" super(Regex,self).__init__() if len(pattern) == 0: warnings.warn("null string passed to Regex; use Empty() instead", SyntaxWarning, stacklevel=2) self.pattern = pattern self.flags = flags try: self.re = re.compile(self.pattern, self.flags) self.reString = self.pattern except sre_constants.error,e: warnings.warn("invalid pattern (%s) passed to Regex" % pattern, SyntaxWarning, stacklevel=2) raise self.name = _ustr(self) self.errmsg = "Expected " + self.name self.myException.msg = self.errmsg self.mayIndexError = False self.mayReturnEmpty = True def parseImpl( self, instring, loc, doActions=True ): result = self.re.match(instring,loc) if not result: exc = self.myException exc.loc = loc exc.pstr = instring raise exc loc = result.end() d = result.groupdict() ret = ParseResults(result.group()) if d: for k in d.keys(): ret[k] = d[k] return loc,ret def __str__( self ): try: return super(Regex,self).__str__() except: pass if self.strRepr is None: self.strRepr = "Re:(%s)" % repr(self.pattern) return self.strRepr class QuotedString(Token): """Token for matching strings that are delimited by quoting characters. """ def __init__( self, quoteChar, escChar=None, escQuote=None, multiline=False, unquoteResults=True, endQuoteChar=None): """ Defined with the following parameters: - quoteChar - string of one or more characters defining the quote delimiting string - escChar - character to escape quotes, typically backslash (default=None) - escQuote - special quote sequence to escape an embedded quote string (such as SQL's "" to escape an embedded ") (default=None) - multiline - boolean indicating whether quotes can span multiple lines (default=False) - unquoteResults - boolean indicating whether the matched text should be unquoted (default=True) - endQuoteChar - string of one or more characters defining the end of the quote delimited string (default=None => same as quoteChar) """ super(QuotedString,self).__init__() # remove white space from quote chars - wont work anyway quoteChar = quoteChar.strip() if len(quoteChar) == 0: warnings.warn("quoteChar cannot be the empty string",SyntaxWarning,stacklevel=2) raise SyntaxError() if endQuoteChar is None: endQuoteChar = quoteChar else: endQuoteChar = endQuoteChar.strip() if len(endQuoteChar) == 0: warnings.warn("endQuoteChar cannot be the empty string",SyntaxWarning,stacklevel=2) raise SyntaxError() self.quoteChar = quoteChar self.quoteCharLen = len(quoteChar) self.firstQuoteChar = quoteChar[0] self.endQuoteChar = endQuoteChar self.endQuoteCharLen = len(endQuoteChar) self.escChar = escChar self.escQuote = escQuote self.unquoteResults = unquoteResults if multiline: self.flags = re.MULTILINE | re.DOTALL self.pattern = r'%s(?:[^%s%s]' % \ ( re.escape(self.quoteChar), _escapeRegexRangeChars(self.endQuoteChar[0]), (escChar is not None and _escapeRegexRangeChars(escChar) or '') ) else: self.flags = 0 self.pattern = r'%s(?:[^%s\n\r%s]' % \ ( re.escape(self.quoteChar), _escapeRegexRangeChars(self.endQuoteChar[0]), (escChar is not None and _escapeRegexRangeChars(escChar) or '') ) if len(self.endQuoteChar) > 1: self.pattern += ( '|(?:' + ')|(?:'.join(["%s[^%s]" % (re.escape(self.endQuoteChar[:i]), _escapeRegexRangeChars(self.endQuoteChar[i])) for i in range(len(self.endQuoteChar)-1,0,-1)]) + ')' ) if escQuote: self.pattern += (r'|(?:%s)' % re.escape(escQuote)) if escChar: self.pattern += (r'|(?:%s.)' % re.escape(escChar)) self.escCharReplacePattern = re.escape(self.escChar)+"(.)" self.pattern += (r')*%s' % re.escape(self.endQuoteChar)) try: self.re = re.compile(self.pattern, self.flags) self.reString = self.pattern except sre_constants.error,e: warnings.warn("invalid pattern (%s) passed to Regex" % self.pattern, SyntaxWarning, stacklevel=2) raise self.name = _ustr(self) self.errmsg = "Expected " + self.name self.myException.msg = self.errmsg self.mayIndexError = False self.mayReturnEmpty = True def parseImpl( self, instring, loc, doActions=True ): result = instring[loc] == self.firstQuoteChar and self.re.match(instring,loc) or None if not result: exc = self.myException exc.loc = loc exc.pstr = instring raise exc loc = result.end() ret = result.group() print ret if self.unquoteResults: # strip off quotes ret = ret[self.quoteCharLen:-self.endQuoteCharLen] if isinstance(ret,basestring): # replace escaped characters if self.escChar: ret = re.sub(self.escCharReplacePattern,"\g<1>",ret) # replace escaped quotes if self.escQuote: ret = ret.replace(self.escQuote, self.endQuoteChar) return loc, ret def __str__( self ): try: return super(QuotedString,self).__str__() except: pass if self.strRepr is None: self.strRepr = "quoted string, starting with %s ending with %s" % (self.quoteChar, self.endQuoteChar) return self.strRepr class CharsNotIn(Token): """Token for matching words composed of characters *not* in a given set. Defined with string containing all disallowed characters, and an optional minimum, maximum, and/or exact length. """ def __init__( self, notChars, min=1, max=0, exact=0 ): super(CharsNotIn,self).__init__() self.skipWhitespace = False self.notChars = notChars self.minLen = min if max > 0: self.maxLen = max else: self.maxLen = sys.maxint if exact > 0: self.maxLen = exact self.minLen = exact self.name = _ustr(self) self.errmsg = "Expected " + self.name self.mayReturnEmpty = ( self.minLen == 0 ) self.myException.msg = self.errmsg self.mayIndexError = False def parseImpl( self, instring, loc, doActions=True ): if instring[loc] in self.notChars: #~ raise ParseException( instring, loc, self.errmsg ) exc = self.myException exc.loc = loc exc.pstr = instring raise exc start = loc loc += 1 notchars = self.notChars maxlen = min( start+self.maxLen, len(instring) ) while loc < maxlen and \ (instring[loc] not in notchars): loc += 1 if loc - start < self.minLen: #~ raise ParseException( instring, loc, self.errmsg ) exc = self.myException exc.loc = loc exc.pstr = instring raise exc return loc, instring[start:loc] def __str__( self ): try: return super(CharsNotIn, self).__str__() except: pass if self.strRepr is None: if len(self.notChars) > 4: self.strRepr = "!W:(%s...)" % self.notChars[:4] else: self.strRepr = "!W:(%s)" % self.notChars return self.strRepr class White(Token): """Special matching class for matching whitespace. Normally, whitespace is ignored by pyparsing grammars. This class is included when some whitespace structures are significant. Define with a string containing the whitespace characters to be matched; default is " \\t\\n". Also takes optional min, max, and exact arguments, as defined for the Word class.""" whiteStrs = { " " : "<SPC>", "\t": "<TAB>", "\n": "<LF>", "\r": "<CR>", "\f": "<FF>", } def __init__(self, ws=" \t\r\n", min=1, max=0, exact=0): super(White,self).__init__() self.matchWhite = ws self.setWhitespaceChars( "".join([c for c in self.whiteChars if c not in self.matchWhite]) ) #~ self.leaveWhitespace() self.name = ("".join([White.whiteStrs[c] for c in self.matchWhite])) self.mayReturnEmpty = True self.errmsg = "Expected " + self.name self.myException.msg = self.errmsg self.minLen = min if max > 0: self.maxLen = max else: self.maxLen = sys.maxint if exact > 0: self.maxLen = exact self.minLen = exact def parseImpl( self, instring, loc, doActions=True ): if not(instring[ loc ] in self.matchWhite): #~ raise ParseException( instring, loc, self.errmsg ) exc = self.myException exc.loc = loc exc.pstr = instring raise exc start = loc loc += 1 maxloc = start + self.maxLen maxloc = min( maxloc, len(instring) ) while loc < maxloc and instring[loc] in self.matchWhite: loc += 1 if loc - start < self.minLen: #~ raise ParseException( instring, loc, self.errmsg ) exc = self.myException exc.loc = loc exc.pstr = instring raise exc return loc, instring[start:loc] class PositionToken(Token): def __init__( self ): super(PositionToken,self).__init__() self.name=self.__class__.__name__ self.mayReturnEmpty = True self.mayIndexError = False class GoToColumn(PositionToken): """Token to advance to a specific column of input text; useful for tabular report scraping.""" def __init__( self, colno ): super(GoToColumn,self).__init__() self.col = colno def preParse( self, instring, loc ): if col(loc,instring) != self.col: instrlen = len(instring) if self.ignoreExprs: loc = self.skipIgnorables( instring, loc ) while loc < instrlen and instring[loc].isspace() and col( loc, instring ) != self.col : loc += 1 return loc def parseImpl( self, instring, loc, doActions=True ): thiscol = col( loc, instring ) if thiscol > self.col: raise ParseException( instring, loc, "Text not in expected column", self ) newloc = loc + self.col - thiscol ret = instring[ loc: newloc ] return newloc, ret class LineStart(PositionToken): """Matches if current position is at the beginning of a line within the parse string""" def __init__( self ): super(LineStart,self).__init__() self.setWhitespaceChars( " \t" ) self.errmsg = "Expected start of line" self.myException.msg = self.errmsg def preParse( self, instring, loc ): preloc = super(LineStart,self).preParse(instring,loc) if instring[preloc] == "\n": loc += 1 return loc def parseImpl( self, instring, loc, doActions=True ): if not( loc==0 or ( loc<len(instring) and instring[loc-1] == "\n" ) ): #col(loc, instring) != 1: #~ raise ParseException( instring, loc, "Expected start of line" ) exc = self.myException exc.loc = loc exc.pstr = instring raise exc return loc, [] class LineEnd(PositionToken): """Matches if current position is at the end of a line within the parse string""" def __init__( self ): super(LineEnd,self).__init__() self.setWhitespaceChars( " \t" ) self.errmsg = "Expected end of line" self.myException.msg = self.errmsg def parseImpl( self, instring, loc, doActions=True ): if loc<len(instring): if instring[loc] == "\n": return loc+1, "\n" else: #~ raise ParseException( instring, loc, "Expected end of line" ) exc = self.myException exc.loc = loc exc.pstr = instring raise exc elif loc == len(instring): return loc+1, [] else: exc = self.myException exc.loc = loc exc.pstr = instring raise exc class StringStart(PositionToken): """Matches if current position is at the beginning of the parse string""" def __init__( self ): super(StringStart,self).__init__() self.errmsg = "Expected start of text" self.myException.msg = self.errmsg def parseImpl( self, instring, loc, doActions=True ): if loc != 0: # see if entire string up to here is just whitespace and ignoreables if loc != self.preParse( instring, 0 ): #~ raise ParseException( instring, loc, "Expected start of text" ) exc = self.myException exc.loc = loc exc.pstr = instring raise exc return loc, [] class StringEnd(PositionToken): """Matches if current position is at the end of the parse string""" def __init__( self ): super(StringEnd,self).__init__() self.errmsg = "Expected end of text" self.myException.msg = self.errmsg def parseImpl( self, instring, loc, doActions=True ): if loc < len(instring): #~ raise ParseException( instring, loc, "Expected end of text" ) exc = self.myException exc.loc = loc exc.pstr = instring raise exc elif loc == len(instring): return loc+1, [] else: exc = self.myException exc.loc = loc exc.pstr = instring raise exc class ParseExpression(ParserElement): """Abstract subclass of ParserElement, for combining and post-processing parsed tokens.""" def __init__( self, exprs, savelist = False ): super(ParseExpression,self).__init__(savelist) if isinstance( exprs, list ): self.exprs = exprs elif isinstance( exprs, basestring ): self.exprs = [ Literal( exprs ) ] else: self.exprs = [ exprs ] def __getitem__( self, i ): return self.exprs[i] def append( self, other ): self.exprs.append( other ) self.strRepr = None return self def leaveWhitespace( self ): """Extends leaveWhitespace defined in base class, and also invokes leaveWhitespace on all contained expressions.""" self.skipWhitespace = False self.exprs = [ e.copy() for e in self.exprs ] for e in self.exprs: e.leaveWhitespace() return self def ignore( self, other ): if isinstance( other, Suppress ): if other not in self.ignoreExprs: super( ParseExpression, self).ignore( other ) for e in self.exprs: e.ignore( self.ignoreExprs[-1] ) else: super( ParseExpression, self).ignore( other ) for e in self.exprs: e.ignore( self.ignoreExprs[-1] ) return self def __str__( self ): try: return super(ParseExpression,self).__str__() except: pass if self.strRepr is None: self.strRepr = "%s:(%s)" % ( self.__class__.__name__, _ustr(self.exprs) ) return self.strRepr def streamline( self ): super(ParseExpression,self).streamline() for e in self.exprs: e.streamline() # collapse nested And's of the form And( And( And( a,b), c), d) to And( a,b,c,d ) # but only if there are no parse actions or resultsNames on the nested And's # (likewise for Or's and MatchFirst's) if ( len(self.exprs) == 2 ): other = self.exprs[0] if ( isinstance( other, self.__class__ ) and not(other.parseAction) and other.resultsName is None and not other.debug ): self.exprs = other.exprs[:] + [ self.exprs[1] ] self.strRepr = None self.mayReturnEmpty |= other.mayReturnEmpty self.mayIndexError |= other.mayIndexError other = self.exprs[-1] if ( isinstance( other, self.__class__ ) and not(other.parseAction) and other.resultsName is None and not other.debug ): self.exprs = self.exprs[:-1] + other.exprs[:] self.strRepr = None self.mayReturnEmpty |= other.mayReturnEmpty self.mayIndexError |= other.mayIndexError return self def setResultsName( self, name, listAllMatches=False ): ret = super(ParseExpression,self).setResultsName(name,listAllMatches) return ret def validate( self, validateTrace=[] ): tmp = validateTrace[:]+[self] for e in self.exprs: e.validate(tmp) self.checkRecursion( [] ) class And(ParseExpression): """Requires all given ParseExpressions to be found in the given order. Expressions may be separated by whitespace. May be constructed using the '+' operator. """ def __init__( self, exprs, savelist = True ): super(And,self).__init__(exprs, savelist) self.mayReturnEmpty = True for e in self.exprs: if not e.mayReturnEmpty: self.mayReturnEmpty = False break self.setWhitespaceChars( exprs[0].whiteChars ) self.skipWhitespace = exprs[0].skipWhitespace def parseImpl( self, instring, loc, doActions=True ): loc, resultlist = self.exprs[0]._parse( instring, loc, doActions ) for e in self.exprs[1:]: loc, exprtokens = e._parse( instring, loc, doActions ) if exprtokens or exprtokens.keys(): resultlist += exprtokens return loc, resultlist def __iadd__(self, other ): if isinstance( other, basestring ): other = Literal( other ) return self.append( other ) #And( [ self, other ] ) def checkRecursion( self, parseElementList ): subRecCheckList = parseElementList[:] + [ self ] for e in self.exprs: e.checkRecursion( subRecCheckList ) if not e.mayReturnEmpty: break def __str__( self ): if hasattr(self,"name"): return self.name if self.strRepr is None: self.strRepr = "{" + " ".join( [ _ustr(e) for e in self.exprs ] ) + "}" return self.strRepr class Or(ParseExpression): """Requires that at least one ParseExpression is found. If two expressions match, the expression that matches the longest string will be used. May be constructed using the '^' operator. """ def __init__( self, exprs, savelist = False ): super(Or,self).__init__(exprs, savelist) self.mayReturnEmpty = False for e in self.exprs: if e.mayReturnEmpty: self.mayReturnEmpty = True break def parseImpl( self, instring, loc, doActions=True ): maxExcLoc = -1 maxMatchLoc = -1 for e in self.exprs: try: loc2 = e.tryParse( instring, loc ) except ParseException, err: if err.loc > maxExcLoc: maxException = err maxExcLoc = err.loc except IndexError, err: if len(instring) > maxExcLoc: maxException = ParseException(instring,len(instring),e.errmsg,self) maxExcLoc = len(instring) else: if loc2 > maxMatchLoc: maxMatchLoc = loc2 maxMatchExp = e if maxMatchLoc < 0: if self.exprs: raise maxException else: raise ParseException(instring, loc, "no defined alternatives to match", self) return maxMatchExp._parse( instring, loc, doActions ) def __ixor__(self, other ): if isinstance( other, basestring ): other = Literal( other ) return self.append( other ) #Or( [ self, other ] ) def __str__( self ): if hasattr(self,"name"): return self.name if self.strRepr is None: self.strRepr = "{" + " ^ ".join( [ _ustr(e) for e in self.exprs ] ) + "}" return self.strRepr def checkRecursion( self, parseElementList ): subRecCheckList = parseElementList[:] + [ self ] for e in self.exprs: e.checkRecursion( subRecCheckList ) class MatchFirst(ParseExpression): """Requires that at least one ParseExpression is found. If two expressions match, the first one listed is the one that will match. May be constructed using the '|' operator. """ def __init__( self, exprs, savelist = False ): super(MatchFirst,self).__init__(exprs, savelist) if exprs: self.mayReturnEmpty = False for e in self.exprs: if e.mayReturnEmpty: self.mayReturnEmpty = True break else: self.mayReturnEmpty = True def parseImpl( self, instring, loc, doActions=True ): maxExcLoc = -1 for e in self.exprs: try: ret = e._parse( instring, loc, doActions ) return ret except ParseException, err: if err.loc > maxExcLoc: maxException = err maxExcLoc = err.loc except IndexError, err: if len(instring) > maxExcLoc: maxException = ParseException(instring,len(instring),e.errmsg,self) maxExcLoc = len(instring) # only got here if no expression matched, raise exception for match that made it the furthest else: if self.exprs: raise maxException else: raise ParseException(instring, loc, "no defined alternatives to match", self) def __ior__(self, other ): if isinstance( other, basestring ): other = Literal( other ) return self.append( other ) #MatchFirst( [ self, other ] ) def __str__( self ): if hasattr(self,"name"): return self.name if self.strRepr is None: self.strRepr = "{" + " | ".join( [ _ustr(e) for e in self.exprs ] ) + "}" return self.strRepr def checkRecursion( self, parseElementList ): subRecCheckList = parseElementList[:] + [ self ] for e in self.exprs: e.checkRecursion( subRecCheckList ) class Each(ParseExpression): """Requires all given ParseExpressions to be found, but in any order. Expressions may be separated by whitespace. May be constructed using the '&' operator. """ def __init__( self, exprs, savelist = True ): super(Each,self).__init__(exprs, savelist) self.mayReturnEmpty = True for e in self.exprs: if not e.mayReturnEmpty: self.mayReturnEmpty = False break self.skipWhitespace = True self.optionals = [ e.expr for e in exprs if isinstance(e,Optional) ] self.multioptionals = [ e.expr for e in exprs if isinstance(e,ZeroOrMore) ] self.multirequired = [ e.expr for e in exprs if isinstance(e,OneOrMore) ] self.required = [ e for e in exprs if not isinstance(e,(Optional,ZeroOrMore,OneOrMore)) ] self.required += self.multirequired def parseImpl( self, instring, loc, doActions=True ): tmpLoc = loc tmpReqd = self.required[:] tmpOpt = self.optionals[:] matchOrder = [] keepMatching = True while keepMatching: tmpExprs = tmpReqd + tmpOpt + self.multioptionals + self.multirequired failed = [] for e in tmpExprs: try: tmpLoc = e.tryParse( instring, tmpLoc ) except ParseException: failed.append(e) else: matchOrder.append(e) if e in tmpReqd: tmpReqd.remove(e) elif e in tmpOpt: tmpOpt.remove(e) if len(failed) == len(tmpExprs): keepMatching = False if tmpReqd: missing = ", ".join( [ _ustr(e) for e in tmpReqd ] ) raise ParseException(instring,loc,"Missing one or more required elements (%s)" % missing ) resultlist = [] for e in matchOrder: loc,results = e._parse(instring,loc,doActions) resultlist.append(results) finalResults = ParseResults([]) for r in resultlist: dups = {} for k in r.keys(): if k in finalResults.keys(): tmp = ParseResults(finalResults[k]) tmp += ParseResults(r[k]) dups[k] = tmp finalResults += ParseResults(r) for k,v in dups.items(): finalResults[k] = v return loc, finalResults def __str__( self ): if hasattr(self,"name"): return self.name if self.strRepr is None: self.strRepr = "{" + " & ".join( [ _ustr(e) for e in self.exprs ] ) + "}" return self.strRepr def checkRecursion( self, parseElementList ): subRecCheckList = parseElementList[:] + [ self ] for e in self.exprs: e.checkRecursion( subRecCheckList ) class ParseElementEnhance(ParserElement): """Abstract subclass of ParserElement, for combining and post-processing parsed tokens.""" def __init__( self, expr, savelist=False ): super(ParseElementEnhance,self).__init__(savelist) if isinstance( expr, basestring ): expr = Literal(expr) self.expr = expr self.strRepr = None if expr is not None: self.mayIndexError = expr.mayIndexError self.setWhitespaceChars( expr.whiteChars ) self.skipWhitespace = expr.skipWhitespace self.saveAsList = expr.saveAsList def parseImpl( self, instring, loc, doActions=True ): if self.expr is not None: return self.expr._parse( instring, loc, doActions ) else: raise ParseException("",loc,self.errmsg,self) def leaveWhitespace( self ): self.skipWhitespace = False self.expr = self.expr.copy() if self.expr is not None: self.expr.leaveWhitespace() return self def ignore( self, other ): if isinstance( other, Suppress ): if other not in self.ignoreExprs: super( ParseElementEnhance, self).ignore( other ) if self.expr is not None: self.expr.ignore( self.ignoreExprs[-1] ) else: super( ParseElementEnhance, self).ignore( other ) if self.expr is not None: self.expr.ignore( self.ignoreExprs[-1] ) return self def streamline( self ): super(ParseElementEnhance,self).streamline() if self.expr is not None: self.expr.streamline() return self def checkRecursion( self, parseElementList ): if self in parseElementList: raise RecursiveGrammarException( parseElementList+[self] ) subRecCheckList = parseElementList[:] + [ self ] if self.expr is not None: self.expr.checkRecursion( subRecCheckList ) def validate( self, validateTrace=[] ): tmp = validateTrace[:]+[self] if self.expr is not None: self.expr.validate(tmp) self.checkRecursion( [] ) def __str__( self ): try: return super(ParseElementEnhance,self).__str__() except: pass if self.strRepr is None and self.expr is not None: self.strRepr = "%s:(%s)" % ( self.__class__.__name__, _ustr(self.expr) ) return self.strRepr class FollowedBy(ParseElementEnhance): """Lookahead matching of the given parse expression. FollowedBy does *not* advance the parsing position within the input string, it only verifies that the specified parse expression matches at the current position. FollowedBy always returns a null token list.""" def __init__( self, expr ): super(FollowedBy,self).__init__(expr) self.mayReturnEmpty = True def parseImpl( self, instring, loc, doActions=True ): self.expr.tryParse( instring, loc ) return loc, [] class NotAny(ParseElementEnhance): """Lookahead to disallow matching with the given parse expression. NotAny does *not* advance the parsing position within the input string, it only verifies that the specified parse expression does *not* match at the current position. Also, NotAny does *not* skip over leading whitespace. NotAny always returns a null token list. May be constructed using the '~' operator.""" def __init__( self, expr ): super(NotAny,self).__init__(expr) #~ self.leaveWhitespace() self.skipWhitespace = False # do NOT use self.leaveWhitespace(), don't want to propagate to exprs self.mayReturnEmpty = True self.errmsg = "Found unwanted token, "+_ustr(self.expr) self.myException = ParseException("",0,self.errmsg,self) def parseImpl( self, instring, loc, doActions=True ): try: self.expr.tryParse( instring, loc ) except (ParseException,IndexError): pass else: #~ raise ParseException(instring, loc, self.errmsg ) exc = self.myException exc.loc = loc exc.pstr = instring raise exc return loc, [] def __str__( self ): if hasattr(self,"name"): return self.name if self.strRepr is None: self.strRepr = "~{" + _ustr(self.expr) + "}" return self.strRepr class ZeroOrMore(ParseElementEnhance): """Optional repetition of zero or more of the given expression.""" def __init__( self, expr ): super(ZeroOrMore,self).__init__(expr) self.mayReturnEmpty = True def parseImpl( self, instring, loc, doActions=True ): tokens = [] try: loc, tokens = self.expr._parse( instring, loc, doActions ) hasIgnoreExprs = ( len(self.ignoreExprs) > 0 ) while 1: if hasIgnoreExprs: preloc = self.skipIgnorables( instring, loc ) else: preloc = loc loc, tmptokens = self.expr._parse( instring, preloc, doActions ) if tmptokens or tmptokens.keys(): tokens += tmptokens except (ParseException,IndexError): pass return loc, tokens def __str__( self ): if hasattr(self,"name"): return self.name if self.strRepr is None: self.strRepr = "[" + _ustr(self.expr) + "]..." return self.strRepr def setResultsName( self, name, listAllMatches=False ): ret = super(ZeroOrMore,self).setResultsName(name,listAllMatches) ret.saveAsList = True return ret class OneOrMore(ParseElementEnhance): """Repetition of one or more of the given expression.""" def parseImpl( self, instring, loc, doActions=True ): # must be at least one loc, tokens = self.expr._parse( instring, loc, doActions ) try: hasIgnoreExprs = ( len(self.ignoreExprs) > 0 ) while 1: if hasIgnoreExprs: preloc = self.skipIgnorables( instring, loc ) else: preloc = loc loc, tmptokens = self.expr._parse( instring, preloc, doActions ) if tmptokens or tmptokens.keys(): tokens += tmptokens except (ParseException,IndexError): pass return loc, tokens def __str__( self ): if hasattr(self,"name"): return self.name if self.strRepr is None: self.strRepr = "{" + _ustr(self.expr) + "}..." return self.strRepr def setResultsName( self, name, listAllMatches=False ): ret = super(OneOrMore,self).setResultsName(name,listAllMatches) ret.saveAsList = True return ret class _NullToken(object): def __bool__(self): return False def __str__(self): return "" _optionalNotMatched = _NullToken() class Optional(ParseElementEnhance): """Optional matching of the given expression. A default return string can also be specified, if the optional expression is not found. """ def __init__( self, exprs, default=_optionalNotMatched ): super(Optional,self).__init__( exprs, savelist=False ) self.defaultValue = default self.mayReturnEmpty = True def parseImpl( self, instring, loc, doActions=True ): try: loc, tokens = self.expr._parse( instring, loc, doActions ) except (ParseException,IndexError): if self.defaultValue is not _optionalNotMatched: tokens = [ self.defaultValue ] else: tokens = [] return loc, tokens def __str__( self ): if hasattr(self,"name"): return self.name if self.strRepr is None: self.strRepr = "[" + _ustr(self.expr) + "]" return self.strRepr class SkipTo(ParseElementEnhance): """Token for skipping over all undefined text until the matched expression is found. If include is set to true, the matched expression is also consumed. The ignore argument is used to define grammars (typically quoted strings and comments) that might contain false matches. """ def __init__( self, other, include=False, ignore=None ): super( SkipTo, self ).__init__( other ) if ignore is not None: self.expr = self.expr.copy() self.expr.ignore(ignore) self.mayReturnEmpty = True self.mayIndexError = False self.includeMatch = include self.asList = False self.errmsg = "No match found for "+_ustr(self.expr) self.myException = ParseException("",0,self.errmsg,self) def parseImpl( self, instring, loc, doActions=True ): startLoc = loc instrlen = len(instring) expr = self.expr while loc <= instrlen: try: loc = expr.skipIgnorables( instring, loc ) expr._parse( instring, loc, doActions=False, callPreParse=False ) if self.includeMatch: skipText = instring[startLoc:loc] loc,mat = expr._parse(instring,loc) if mat: return loc, [ skipText, mat ] else: return loc, [ skipText ] else: return loc, [ instring[startLoc:loc] ] except (ParseException,IndexError): loc += 1 exc = self.myException exc.loc = loc exc.pstr = instring raise exc class Forward(ParseElementEnhance): """Forward declaration of an expression to be defined later - used for recursive grammars, such as algebraic infix notation. When the expression is known, it is assigned to the Forward variable using the '<<' operator. Note: take care when assigning to Forward not to overlook precedence of operators. Specifically, '|' has a lower precedence than '<<', so that:: fwdExpr << a | b | c will actually be evaluated as:: (fwdExpr << a) | b | c thereby leaving b and c out as parseable alternatives. It is recommended that you explicitly group the values inserted into the Forward:: fwdExpr << (a | b | c) """ def __init__( self, other=None ): super(Forward,self).__init__( other, savelist=False ) def __lshift__( self, other ): if isinstance( other, basestring ): other = Literal(other) self.expr = other self.mayReturnEmpty = other.mayReturnEmpty self.strRepr = None return self def leaveWhitespace( self ): self.skipWhitespace = False return self def streamline( self ): if not self.streamlined: self.streamlined = True if self.expr is not None: self.expr.streamline() return self def validate( self, validateTrace=[] ): if self not in validateTrace: tmp = validateTrace[:]+[self] if self.expr is not None: self.expr.validate(tmp) self.checkRecursion([]) def __str__( self ): if hasattr(self,"name"): return self.name self.__class__ = _ForwardNoRecurse try: if self.expr is not None: retString = _ustr(self.expr) else: retString = "None" finally: self.__class__ = Forward return "Forward: "+retString def copy(self): if self.expr is not None: return super(Forward,self).copy() else: ret = Forward() ret << self return ret class _ForwardNoRecurse(Forward): def __str__( self ): return "..." class TokenConverter(ParseElementEnhance): """Abstract subclass of ParseExpression, for converting parsed results.""" def __init__( self, expr, savelist=False ): super(TokenConverter,self).__init__( expr )#, savelist ) self.saveAsList = False class Upcase(TokenConverter): """Converter to upper case all matching tokens.""" def __init__(self, *args): super(Upcase,self).__init__(*args) def postParse( self, instring, loc, tokenlist ): return map( string.upper, tokenlist ) class Downcase(TokenConverter): """Converter to upper case all matching tokens.""" def __init__(self, *args): super(Downcase,self).__init__(*args) def postParse( self, instring, loc, tokenlist ): return map( string.lower, tokenlist ) class Combine(TokenConverter): """Converter to concatenate all matching tokens to a single string. By default, the matching patterns must also be contiguous in the input string; this can be disabled by specifying 'adjacent=False' in the constructor. """ def __init__( self, expr, joinString="", adjacent=True ): super(Combine,self).__init__( expr ) # suppress whitespace-stripping in contained parse expressions, but re-enable it on the Combine itself if adjacent: self.leaveWhitespace() self.adjacent = adjacent self.skipWhitespace = True self.joinString = joinString def ignore( self, other ): if self.adjacent: ParserElement.ignore(self, other) else: super( Combine, self).ignore( other ) return self def postParse( self, instring, loc, tokenlist ): retToks = tokenlist.copy() del retToks[:] retToks += ParseResults([ "".join(tokenlist._asStringList(self.joinString)) ], modal=self.modalResults) if self.resultsName and len(retToks.keys())>0: return [ retToks ] else: return retToks class Group(TokenConverter): """Converter to return the matched tokens as a list - useful for returning tokens of ZeroOrMore and OneOrMore expressions.""" def __init__( self, expr ): super(Group,self).__init__( expr ) self.saveAsList = True def postParse( self, instring, loc, tokenlist ): return [ tokenlist ] class Dict(TokenConverter): """Converter to return a repetitive expression as a list, but also as a dictionary. Each element can also be referenced using the first token in the expression as its key. Useful for tabular report scraping when the first column can be used as a item key. """ def __init__( self, exprs ): super(Dict,self).__init__( exprs ) self.saveAsList = True def postParse( self, instring, loc, tokenlist ): for i,tok in enumerate(tokenlist): ikey = _ustr(tok[0]).strip() if len(tok)==1: tokenlist[ikey] = ("",i) elif len(tok)==2 and not isinstance(tok[1],ParseResults): tokenlist[ikey] = (tok[1],i) else: dictvalue = tok.copy() #ParseResults(i) del dictvalue[0] if len(dictvalue)!= 1 or (isinstance(dictvalue,ParseResults) and dictvalue.keys()): tokenlist[ikey] = (dictvalue,i) else: tokenlist[ikey] = (dictvalue[0],i) if self.resultsName: return [ tokenlist ] else: return tokenlist class Suppress(TokenConverter): """Converter for ignoring the results of a parsed expression.""" def postParse( self, instring, loc, tokenlist ): return [] def suppress( self ): return self class OnlyOnce(object): """Wrapper for parse actions, to ensure they are only called once.""" def __init__(self, methodCall): self.callable = ParserElement.normalizeParseActionArgs(methodCall) self.called = False def __call__(self,s,l,t): if not self.called: results = self.callable(s,l,t) self.called = True return results raise ParseException(s,l,"") def reset(): self.called = False def traceParseAction(f): """Decorator for debugging parse actions.""" f = ParserElement.normalizeParseActionArgs(f) def z(*paArgs): thisFunc = f.func_name s,l,t = paArgs[-3:] if len(paArgs)>3: thisFunc = paArgs[0].__class__.__name__ + '.' + thisFunc sys.stderr.write( ">>entering %s(line: '%s', %d, %s)\n" % (thisFunc,line(l,s),l,t) ) try: ret = f(*paArgs) except Exception, exc: sys.stderr.write( "<<leaving %s (exception: %s)\n" % (thisFunc,exc) ) raise sys.stderr.write( "<<leaving %s (ret: %s)\n" % (thisFunc,ret) ) return ret return z # # global helpers # def delimitedList( expr, delim=",", combine=False ): """Helper to define a delimited list of expressions - the delimiter defaults to ','. By default, the list elements and delimiters can have intervening whitespace, and comments, but this can be overridden by passing 'combine=True' in the constructor. If combine is set to True, the matching tokens are returned as a single token string, with the delimiters included; otherwise, the matching tokens are returned as a list of tokens, with the delimiters suppressed. """ dlName = _ustr(expr)+" ["+_ustr(delim)+" "+_ustr(expr)+"]..." if combine: return Combine( expr + ZeroOrMore( delim + expr ) ).setName(dlName) else: return ( expr + ZeroOrMore( Suppress( delim ) + expr ) ).setName(dlName) def countedArray( expr ): """Helper to define a counted list of expressions. This helper defines a pattern of the form:: integer expr expr expr... where the leading integer tells how many expr expressions follow. The matched tokens returns the array of expr tokens as a list - the leading count token is suppressed. """ arrayExpr = Forward() def countFieldParseAction(s,l,t): n = int(t[0]) arrayExpr << (n and Group(And([expr]*n)) or Group(empty)) return [] return ( Word(nums).setParseAction(countFieldParseAction) + arrayExpr ) def _flatten(L): if type(L) is not list: return [L] if L == []: return L return _flatten(L[0]) + _flatten(L[1:]) def matchPreviousLiteral(expr): """Helper to define an expression that is indirectly defined from the tokens matched in a previous expression, that is, it looks for a 'repeat' of a previous expression. For example:: first = Word(nums) second = matchPreviousLiteral(first) matchExpr = first + ":" + second will match "1:1", but not "1:2". Because this matches a previous literal, will also match the leading "1:1" in "1:10". If this is not desired, use matchPreviousExpr. Do *not* use with packrat parsing enabled. """ rep = Forward() def copyTokenToRepeater(s,l,t): if t: if len(t) == 1: rep << t[0] else: # flatten t tokens tflat = _flatten(t.asList()) rep << And( [ Literal(tt) for tt in tflat ] ) else: rep << Empty() expr.addParseAction(copyTokenToRepeater) return rep def matchPreviousExpr(expr): """Helper to define an expression that is indirectly defined from the tokens matched in a previous expression, that is, it looks for a 'repeat' of a previous expression. For example:: first = Word(nums) second = matchPreviousExpr(first) matchExpr = first + ":" + second will match "1:1", but not "1:2". Because this matches by expressions, will *not* match the leading "1:1" in "1:10"; the expressions are evaluated first, and then compared, so "1" is compared with "10". Do *not* use with packrat parsing enabled. """ rep = Forward() e2 = expr.copy() rep << e2 def copyTokenToRepeater(s,l,t): matchTokens = _flatten(t.asList()) def mustMatchTheseTokens(s,l,t): theseTokens = _flatten(t.asList()) if theseTokens != matchTokens: raise ParseException("",0,"") rep.setParseAction( mustMatchTheseTokens ) expr.addParseAction(copyTokenToRepeater) return rep def _escapeRegexRangeChars(s): #~ escape these chars: ^-] for c in r"\^-]": s = s.replace(c,"\\"+c) s = s.replace("\n",r"\n") s = s.replace("\t",r"\t") return _ustr(s) def oneOf( strs, caseless=False, useRegex=True ): """Helper to quickly define a set of alternative Literals, and makes sure to do longest-first testing when there is a conflict, regardless of the input order, but returns a MatchFirst for best performance. Parameters: - strs - a string of space-delimited literals, or a list of string literals - caseless - (default=False) - treat all literals as caseless - useRegex - (default=True) - as an optimization, will generate a Regex object; otherwise, will generate a MatchFirst object (if caseless=True, or if creating a Regex raises an exception) """ if caseless: isequal = ( lambda a,b: a.upper() == b.upper() ) masks = ( lambda a,b: b.upper().startswith(a.upper()) ) parseElementClass = CaselessLiteral else: isequal = ( lambda a,b: a == b ) masks = ( lambda a,b: b.startswith(a) ) parseElementClass = Literal if isinstance(strs,(list,tuple)): symbols = strs[:] elif isinstance(strs,basestring): symbols = strs.split() else: warnings.warn("Invalid argument to oneOf, expected string or list", SyntaxWarning, stacklevel=2) i = 0 while i < len(symbols)-1: cur = symbols[i] for j,other in enumerate(symbols[i+1:]): if ( isequal(other, cur) ): del symbols[i+j+1] break elif ( masks(cur, other) ): del symbols[i+j+1] symbols.insert(i,other) cur = other break else: i += 1 if not caseless and useRegex: #~ print strs,"->", "|".join( [ _escapeRegexChars(sym) for sym in symbols] ) try: if len(symbols)==len("".join(symbols)): return Regex( "[%s]" % "".join( [ _escapeRegexRangeChars(sym) for sym in symbols] ) ) else: return Regex( "|".join( [ re.escape(sym) for sym in symbols] ) ) except: warnings.warn("Exception creating Regex for oneOf, building MatchFirst", SyntaxWarning, stacklevel=2) # last resort, just use MatchFirst return MatchFirst( [ parseElementClass(sym) for sym in symbols ] ) def dictOf( key, value ): """Helper to easily and clearly define a dictionary by specifying the respective patterns for the key and value. Takes care of defining the Dict, ZeroOrMore, and Group tokens in the proper order. The key pattern can include delimiting markers or punctuation, as long as they are suppressed, thereby leaving the significant key text. The value pattern can include named results, so that the Dict results can include named token fields. """ return Dict( ZeroOrMore( Group ( key + value ) ) ) _bslash = "\\" printables = "".join( [ c for c in string.printable if c not in string.whitespace ] ) # convenience constants for positional expressions empty = Empty().setName("empty") lineStart = LineStart().setName("lineStart") lineEnd = LineEnd().setName("lineEnd") stringStart = StringStart().setName("stringStart") stringEnd = StringEnd().setName("stringEnd") _escapedPunc = Word( _bslash, r"\[]-*.$+^?()~ ", exact=2 ).setParseAction(lambda s,l,t:t[0][1]) _printables_less_backslash = "".join([ c for c in printables if c not in r"\]" ]) _escapedHexChar = Combine( Suppress(_bslash + "0x") + Word(hexnums) ).setParseAction(lambda s,l,t:unichr(int(t[0],16))) _escapedOctChar = Combine( Suppress(_bslash) + Word("0","01234567") ).setParseAction(lambda s,l,t:unichr(int(t[0],8))) _singleChar = _escapedPunc | _escapedHexChar | _escapedOctChar | Word(_printables_less_backslash,exact=1) _charRange = Group(_singleChar + Suppress("-") + _singleChar) _reBracketExpr = "[" + Optional("^").setResultsName("negate") + Group( OneOrMore( _charRange | _singleChar ) ).setResultsName("body") + "]" _expanded = lambda p: (isinstance(p,ParseResults) and ''.join([ unichr(c) for c in range(ord(p[0]),ord(p[1])+1) ]) or p) def srange(s): r"""Helper to easily define string ranges for use in Word construction. Borrows syntax from regexp '[]' string range definitions:: srange("[0-9]") -> "0123456789" srange("[a-z]") -> "abcdefghijklmnopqrstuvwxyz" srange("[a-z$_]") -> "abcdefghijklmnopqrstuvwxyz$_" The input string must be enclosed in []'s, and the returned string is the expanded character set joined into a single string. The values enclosed in the []'s may be:: a single character an escaped character with a leading backslash (such as \- or \]) an escaped hex character with a leading '\0x' (\0x21, which is a '!' character) an escaped octal character with a leading '\0' (\041, which is a '!' character) a range of any of the above, separated by a dash ('a-z', etc.) any combination of the above ('aeiouy', 'a-zA-Z0-9_$', etc.) """ try: return "".join([_expanded(part) for part in _reBracketExpr.parseString(s).body]) except: return "" def replaceWith(replStr): """Helper method for common parse actions that simply return a literal value. Especially useful when used with transformString(). """ def _replFunc(*args): return [replStr] return _replFunc def removeQuotes(s,l,t): """Helper parse action for removing quotation marks from parsed quoted strings. To use, add this parse action to quoted string using:: quotedString.setParseAction( removeQuotes ) """ return t[0][1:-1] def upcaseTokens(s,l,t): """Helper parse action to convert tokens to upper case.""" return [ str(tt).upper() for tt in t ] def downcaseTokens(s,l,t): """Helper parse action to convert tokens to lower case.""" return [ str(tt).lower() for tt in t ] def keepOriginalText(s,startLoc,t): import inspect """Helper parse action to preserve original parsed text, overriding any nested parse actions.""" f = inspect.stack()[1][0] try: endloc = f.f_locals["loc"] finally: del f return s[startLoc:endloc] def _makeTags(tagStr, xml): """Internal helper to construct opening and closing tag expressions, given a tag name""" tagAttrName = Word(alphanums) if (xml): tagAttrValue = dblQuotedString.copy().setParseAction( removeQuotes ) openTag = Suppress("<") + Keyword(tagStr) + \ Dict(ZeroOrMore(Group( tagAttrName + Suppress("=") + tagAttrValue ))) + \ Optional("/",default=[False]).setResultsName("empty").setParseAction(lambda s,l,t:t[0]=='/') + Suppress(">") else: printablesLessRAbrack = "".join( [ c for c in printables if c not in ">" ] ) tagAttrValue = quotedString.copy().setParseAction( removeQuotes ) | Word(printablesLessRAbrack) openTag = Suppress("<") + Keyword(tagStr,caseless=True) + \ Dict(ZeroOrMore(Group( tagAttrName.setParseAction(downcaseTokens) + \ Suppress("=") + tagAttrValue ))) + \ Optional("/",default=[False]).setResultsName("empty").setParseAction(lambda s,l,t:t[0]=='/') + Suppress(">") closeTag = Combine("</" + Keyword(tagStr,caseless=not xml) + ">") openTag = openTag.setResultsName("start"+"".join(tagStr.replace(":"," ").title().split())).setName("<%s>" % tagStr) closeTag = closeTag.setResultsName("end"+"".join(tagStr.replace(":"," ").title().split())).setName("</%s>" % tagStr) return openTag, closeTag def makeHTMLTags(tagStr): """Helper to construct opening and closing tag expressions for HTML, given a tag name""" return _makeTags( tagStr, False ) def makeXMLTags(tagStr): """Helper to construct opening and closing tag expressions for XML, given a tag name""" return _makeTags( tagStr, True ) opAssoc = _Constants() opAssoc.LEFT = object() opAssoc.RIGHT = object() def operatorPrecedence( baseExpr, opList ): """Helper method for constructing grammars of expressions made up of operators working in a precedence hierarchy. Operators may be unary or binary, left- or right-associative. Parse actions can also be attached to operator expressions. Parameters: - baseExpr - expression representing the most basic element for the nested - opList - list of tuples, one for each operator precedence level in the expression grammar; each tuple is of the form (opExpr, numTerms, rightLeftAssoc, parseAction), where: - opExpr is the pyparsing expression for the operator; may also be a string, which will be converted to a Literal - numTerms is the number of terms for this operator (must be 1 or 2) - rightLeftAssoc is the indicator whether the operator is right or left associative, using the pyparsing-defined constants opAssoc.RIGHT and opAssoc.LEFT. - parseAction is the parse action to be associated with expressions matching this operator expression (the parse action tuple member may be omitted) """ ret = Forward() lastExpr = baseExpr | ( Suppress('(') + ret + Suppress(')') ) for i,operDef in enumerate(opList): opExpr,arity,rightLeftAssoc,pa = (operDef + (None,))[:4] thisExpr = Forward().setName("expr%d" % i) if rightLeftAssoc == opAssoc.LEFT: if arity == 1: matchExpr = Group( lastExpr + opExpr ) elif arity == 2: matchExpr = Group( lastExpr + OneOrMore( opExpr + lastExpr ) ) else: raise ValueError, "operator must be unary (1) or binary (2)" elif rightLeftAssoc == opAssoc.RIGHT: if arity == 1: # try to avoid LR with this extra test if not isinstance(opExpr, Optional): opExpr = Optional(opExpr) matchExpr = FollowedBy(opExpr.expr + thisExpr) + Group( opExpr + thisExpr ) elif arity == 2: matchExpr = Group( lastExpr + OneOrMore( opExpr + thisExpr ) ) else: raise ValueError, "operator must be unary (1) or binary (2)" else: raise ValueError, "operator must indicate right or left associativity" if pa: matchExpr.setParseAction( pa ) thisExpr << ( matchExpr | lastExpr ) lastExpr = thisExpr ret << lastExpr return ret alphas8bit = srange(r"[\0xc0-\0xd6\0xd8-\0xf6\0xf8-\0xfe]") dblQuotedString = Regex(r'"(?:[^"\n\r\\]|(?:"")|(?:\\.))*"').setName("string enclosed in double quotes") sglQuotedString = Regex(r"'(?:[^'\n\r\\]|(?:'')|(?:\\.))*'").setName("string enclosed in single quotes") quotedString = Regex(r'''(?:"(?:[^"\n\r\\]|(?:"")|(?:\\.))*")|(?:'(?:[^'\n\r\\]|(?:'')|(?:\\.))*')''').setName("quotedString using single or double quotes") # it's easy to get these comment structures wrong - they're very common, so may as well make them available cStyleComment = Regex(r"/\*(?:[^*]*\*+)+?/").setName("C style comment") htmlComment = Regex(r"<!--[\s\S]*?-->") restOfLine = Regex(r".*").leaveWhitespace() dblSlashComment = Regex(r"\/\/(\\\n|.)*").setName("// comment") cppStyleComment = Regex(r"/(?:\*(?:[^*]*\*+)+?/|/[^\n]*(?:\n[^\n]*)*?(?:(?<!\\)|\Z))").setName("C++ style comment") javaStyleComment = cppStyleComment pythonStyleComment = Regex(r"#.*").setName("Python style comment") _noncomma = "".join( [ c for c in printables if c != "," ] ) _commasepitem = Combine(OneOrMore(Word(_noncomma) + Optional( Word(" \t") + ~Literal(",") + ~LineEnd() ) ) ).streamline().setName("commaItem") commaSeparatedList = delimitedList( Optional( quotedString | _commasepitem, default="") ).setName("commaSeparatedList") if __name__ == "__main__": def test( teststring ): print teststring,"->", try: tokens = simpleSQL.parseString( teststring ) tokenlist = tokens.asList() print tokenlist print "tokens = ", tokens print "tokens.columns =", tokens.columns print "tokens.tables =", tokens.tables print tokens.asXML("SQL",True) except ParseException, err: print err.line print " "*(err.column-1) + "^" print err print selectToken = CaselessLiteral( "select" ) fromToken = CaselessLiteral( "from" ) ident = Word( alphas, alphanums + "_$" ) columnName = delimitedList( ident, ".", combine=True ).setParseAction( upcaseTokens ) columnNameList = Group( delimitedList( columnName ) )#.setName("columns") tableName = delimitedList( ident, ".", combine=True ).setParseAction( upcaseTokens ) tableNameList = Group( delimitedList( tableName ) )#.setName("tables") simpleSQL = ( selectToken + \ ( '*' | columnNameList ).setResultsName( "columns" ) + \ fromToken + \ tableNameList.setResultsName( "tables" ) ) test( "SELECT * from XYZZY, ABC" ) test( "select * from SYS.XYZZY" ) test( "Select A from Sys.dual" ) test( "Select AA,BB,CC from Sys.dual" ) test( "Select A, B, C from Sys.dual" ) test( "Select A, B, C from Sys.dual" ) test( "Xelect A, B, C from Sys.dual" ) test( "Select A, B, C frox Sys.dual" ) test( "Select" ) test( "Select ^^^ frox Sys.dual" ) test( "Select A, B, C from Sys.dual, Table2 " )