pyparsing.py

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# module pyparsing.py
#
# Copyright (c) 2003,2004 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.
#
# Todo:
# - add pprint() - pretty-print output of defined BNF
#
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__ = "1.2.1"
__versionTime__ = "19 August 04 12:24"
__author__ = "Paul McGuire <ptmcg@users.sourceforge.net>"

import string
import copy,sys
#~ sys.stderr.write( "testing pyparsing module, version %s, %s\n" % (__version__,__versionTime__ ) )

class ParseException(Exception):
"""exception thrown when parse expressions don't match class"""
__slots__ = ( "loc","msg","pstr" )
# Performance tuning: we construct a *lot* of these, so keep this
# constructor as small and fast as possible
def __init__( self, pstr, loc, msg ):
self.loc = loc
self.msg = msg
self.pstr = pstr

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 (%d), (%d,%d)" % ( self.msg, self.loc, self.lineno, self.column )
def __repr__( self ):
return str(self)

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", "__modal" )
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.__modal = modal
if type(toklist) is list:
self.__toklist = toklist[:]
else:
self.__toklist = [toklist]
self.__tokdict = {}

if name:
self.__name = name
if 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 TypeError:
self[name] = toklist

def __getitem__( self, i ):
if isinstance( i, int ) or isinstance( i, slice ):
return self.__toklist[i]
else:
if self.__modal:
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]
else:
self.__tokdict[k] = self.__tokdict.get(k,list()) + [(v,0)]
sub = v
if isinstance(sub,ParseResults):
sub.__parent = self

def __delitem__( self, i ):
del self.__toklist[i]

def __contains__( self, k ):
return self.__tokdict.has_key(k)

def __len__( self ): return len( self.__toklist )
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,v[-1][0]) for k,v in self.__tokdict.items()]

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 self.__modal:
return self.__tokdict[name][-1][0]
else:
return ParseResults([ v[0] for v in self.__tokdict[name] ])
else:
return ""
return None

def __iadd__( self, other ):
offset = len(self.__toklist)
self.__toklist += other.__toklist
if other.__tokdict:
addOffset = lambda a: (a<0 and offset) or (a + offset)
otherdictitems = [(k,(v[0],addOffset(v[1])) ) for (k,vlist) in other.__tokdict.items() for v in vlist]
for k,v in otherdictitems:
self[k] = v
if isinstance(v[0],ParseResults):
v[0].__parent = self
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 + str(i)
else:
out += sep + repr(i)
sep = ", "
out += "]"
return out

def _asStringList( self ):
out = []
for item in self.__toklist:
if isinstance( item, ParseResults ):
out += item._asStringList()
else:
out += 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 copy( self ):
"""Returns a new copy of a ParseResults object."""
ret = ParseResults( self.__toklist )
ret.__tokdict = self.__tokdict.copy()
ret.__parent = self.__parent
ret.__modal = self.__modal
ret.__name = self.__name
return ret

def asXML( self, doctag=None, namedItemsOnly=False, indent="" ):
"""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 ] )

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, indent+" ")]
else:
out += [ res.asXML(None, namedItemsOnly and doctag is None, indent+" ")]
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"
out += [ nl, indent, " ", "<", resTag, ">", str(res), "</", 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

col = lambda loc,strg: loc - strg.rfind("\n", 0, loc)
col.__doc__ = """Returns current column within a string, counting newlines as line separators
The first column is number 1.
"""

lineno = lambda loc,strg: strg.count("\n",0,loc) + 1
lineno.__doc__ = """Returns current line number within a string, counting newlines as line separators
The first line is number 1.
"""

def line( loc, strg ):
"""Returns the line of text containing loc within a string, counting newlines as line separators
The first line is number 1.
"""
lastCR = strg.rfind("\n", 0, loc)
nextCR = strg.find("\n", loc)
if nextCR > 0:
return strg[lastCR+1:nextCR]
else:
return strg[lastCR+1:]

class ParserElement(object):
"""Abstract base level parser element class."""
def __init__( self, savelist=False ):
self.parseAction = None
#~ self.name = "<unknown>" # don't define self.name, let subclasses try/except upcall
self.strRepr = None
self.resultsName = None
self.saveList = savelist
self.skipWhitespace = True
self.whiteChars = " \n\t\r"
self.mayReturnEmpty = False
self.keepTabs = False
self.ignoreExprs = []
self.debug = False
self.streamlined = False
self.mayIndexError = True
self.errmsg = ""
self.modalResults = True

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 ParseElement 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 = copy.copy( self )
newself.resultsName = name
newself.modalResults = not listAllMatches
return newself

def setParseAction( self, fn ):
"""Define action to perform when successfully matching parse element definition.
Parse action fn is a callable method with the arguments (s, loc, toks) where:
- s = the original string being parsed
- loc = the location of the matching substring
- toks = a list of the matched tokens
If the function fn modifies the tokens, it 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 = 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

def parse( self, instring, loc, doActions=True ):
debugging = ( self.debug and doActions )

if debugging:
print "Match",self,"at loc",loc,"(%d,%d)" % ( lineno(loc,instring), col(loc,instring) )
loc = self.preParse( instring, loc )
tokensStart = loc
try:
loc,tokens = self.parseImpl( instring, loc, doActions )
except IndexError:
raise ParseException, ( instring, len(instring), self.errmsg )
except ParseException, err:
print "Exception raised:", err
raise
else:
loc = self.preParse( instring, loc )
tokensStart = loc
if self.mayIndexError or loc >= len(instring):
try:
loc,tokens = self.parseImpl( instring, loc, doActions )
except IndexError:
raise ParseException, ( instring, len(instring), self.errmsg )
else:
loc,tokens = self.parseImpl( instring, loc, doActions )

tokens = self.postParse( instring, loc, tokens )

retTokens = ParseResults( tokens, self.resultsName, asList=self.saveList, modal=self.modalResults )
if self.parseAction and doActions:
if debugging:
try:
tokens = self.parseAction( instring, tokensStart, retTokens )
if tokens is not None:
if isinstance(tokens,tuple):
tokens = tokens[1]
retTokens = ParseResults( tokens, self.resultsName, asList=self.saveList, modal=self.modalResults )
except ParseException, err:
print "Exception raised in user parse action:", err
raise
else:
tokens = self.parseAction( instring, tokensStart, retTokens )
if tokens is not None:
if isinstance(tokens,tuple):
tokens = tokens[1]
retTokens = ParseResults( tokens,
self.resultsName,
asList=self.saveList and (isinstance(tokens,ParseResults) or isinstance(tokens,list) ),
modal=self.modalResults )

if debugging:
print "Matched",self,"->",retTokens.asList()

return loc, retTokens

def tryParse( self, instring, loc ):
return self.parse( instring, loc, doActions=False )

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.
"""
if not self.streamlined:
self.streamline()
self.saveList = 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 ):
"""Scan the input string for expression matches. Each match will return the matching tokens, start location, and end location."""
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
while loc < instrlen:
try:
loc = preparseFn( instring, loc )
nextLoc,tokens = parseFn( instring, loc )
except ParseException:
loc += 1
else:
yield tokens, loc, 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 __add__(self, other ):
"""Implementation of + operator - returns And"""
if isinstance( other, str ):
other = Literal( other )
return And( [ self, other ] )

def __radd__(self, other ):
"""Implementation of += operator"""
if isinstance( other, str ):
other = Literal( other )
return other + self

def __or__(self, other ):
"""Implementation of | operator - returns MatchFirst"""
if isinstance( other, str ):
other = Literal( other )
return MatchFirst( [ self, other ] )

def __ror__(self, other ):
"""Implementation of |= operator"""
if isinstance( other, str ):
other = Literal( other )
return other | self

def __xor__(self, other ):
"""Implementation of ^ operator - returns Or"""
if isinstance( other, str ):
other = Literal( other )
return Or( [ self, other ] )

def __rxor__(self, other ):
"""Implementation of ^= operator"""
if isinstance( other, str ):
other = Literal( other )
return other ^ self

def __invert__( self ):
"""Implementation of ~ operator - returns NotAny"""
return NotAny( self )

def suppress( self ):
"""Suppresses the output of this ParseElement; useful to keep punctuation from
cluttering up returned output.
"""
return Suppress( self )

def leaveWhitespace( self ):
self.skipWhitespace = 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 setDebug( self, flag=True ):
"""Enable display of debugging messages while doing pattern matching."""
self.debug = flag
return self

def __str__( self ):
return self.name

def __repr__( self ):
return str(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,"")

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 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:
sys.stderr.write("\nnull string passed to Literal; use Empty() instead\n")
raise
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
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 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 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.initChars = initChars
if bodyChars :
self.bodyChars = bodyChars
else:
self.bodyChars = initChars

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 = str(self)
self.errmsg = "Expected " + self.name
self.myException.msg = self.errmsg
self.mayIndexError = False

def parseImpl( self, instring, loc, doActions=True ):
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
bodychars = self.bodyChars
maxloc = start + self.maxLen
maxloc = min( maxloc, len(instring) )
while loc < maxloc and instring[loc] in bodychars:
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(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.initChars != self.bodyChars ):
self.strRepr = "W:(%s,%s)" % ( charsAsStr(self.initChars), charsAsStr(self.bodyChars) )
else:
self.strRepr = "W:(%s)" % charsAsStr(self.initChars)

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 = str(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>",
}
def __init__(self, ws=" \t\r\n", min=1, max=0, exact=0):
super(White,self).__init__()
self.matchWhite = ws
self.whiteChars = "".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

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" )
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.whiteChars = " \t"
self.errmsg = "Expected start of line"
self.myException.msg = self.errmsg

def preParse( self, instring, loc ):
loc = super(LineStart,self).preParse(instring,loc)
if instring[loc] == "\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.whiteChars = " \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
else:
return loc, []

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
return loc, []

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, str ):
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 ):
self.skipWhitespace = False
self.exprs = [ copy.copy(e) 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__, str(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
other.parseAction is None and
other.resultsName is None and
not other.debug ):
self.exprs = other.exprs[:] + [ self.exprs[1] ]
self.strRepr = None

other = self.exprs[-1]
if ( isinstance( other, self.__class__ ) and
other.parseAction is None and
other.resultsName is None and
not other.debug ):
self.exprs = self.exprs[:-1] + other.exprs[:]
self.strRepr = None

return self

def setResultsName( self, name, listAllMatches=False ):
ret = super(ParseExpression,self).setResultsName(name,listAllMatches)
ret.saveList = True
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 = False ):
super(And,self).__init__(exprs, savelist)
self.mayReturnEmpty = True
for e in exprs:
if not e.mayReturnEmpty:
self.mayReturnEmpty = False
break
self.skipWhitespace = exprs[0].skipWhitespace
self.whiteChars = exprs[0].whiteChars

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, str ):
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( [ str(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 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, tokenlist = 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)
maxExcLoc = len(instring)
else:
if loc2 > maxMatchLoc:
maxMatchLoc = loc2
maxMatchExp = e

if maxMatchLoc < 0:
raise maxException

return maxMatchExp.parse( instring, loc, doActions )

def __ixor__(self, other ):
if isinstance( other, str ):
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( [ str(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)
self.mayReturnEmpty = False
for e in exprs:
if e.mayReturnEmpty:
self.mayReturnEmpty = True
break

def parseImpl( self, instring, loc, doActions=True ):
maxExcLoc = -1
for e in self.exprs:
try:
return e.parse( 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)
maxExcLoc = len(instring)

# only got here if no expression matched, raise exception for match that made it the furthest
else:
raise maxException

def __ior__(self, other ):
if isinstance( other, str ):
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( [ str(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, str ):
expr = Literal(expr)
self.expr = expr
self.strRepr = None
if expr is not None:
self.mayIndexError = expr.mayIndexError
self.skipWhitespace = expr.skipWhitespace
self.whiteChars = expr.whiteChars

def parseImpl( self, instring, loc, doActions=True ):
if self.expr is not None:
return self.expr.parse( instring, loc, doActions )
else:
raise ParseException(loc,"",instring)

def leaveWhitespace( self ):
self.skipWhitespace = False
self.expr = copy.copy(self.expr)
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__, str(self.expr) )
return self.strRepr

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."""
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 unexpected token, "+str(self.expr)
self.myException = ParseException("",0,self.errmsg)

def parseImpl( self, instring, loc, doActions=True ):
try:
loc2, tokenlist = 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 = "~{" + str(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:
loc = self.skipIgnorables( instring, loc )
loc, tmptokens = self.expr.parse( instring, loc, 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 = "[" + str(self.expr) + "]..."

return self.strRepr

def setResultsName( self, name, listAllMatches=False ):
ret = super(ZeroOrMore,self).setResultsName(name,listAllMatches)
ret.saveList = 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:
loc = self.skipIgnorables( instring, loc )
loc, tmptokens = self.expr.parse( instring, loc, 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 = "{" + str(self.expr) + "}..."

return self.strRepr

def setResultsName( self, name, listAllMatches=False ):
ret = super(OneOrMore,self).setResultsName(name,listAllMatches)
ret.saveList = True
return ret

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=None ):
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 None:
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 = "[" + str(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 = copy.copy( self.expr )
self.expr.ignore(ignore)
self.mayReturnEmpty = True
self.mayIndexError = False
self.includeMatch = include
self.errmsg = "No match found for "+str(self.expr)
self.myException = ParseException("",0,self.errmsg)

def parseImpl( self, instring, loc, doActions=True ):
startLoc = loc
instrlen = len(instring)
expr = self.expr
while loc < instrlen:
try:
expr.tryParse(instring, loc)
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.
"""
def __init__( self, other=None ):
super(Forward,self).__init__( other, savelist=False )

def __lshift__( self, 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

strmethod = self.__str__
self.__class__ = _ForwardNoRecurse
if self.expr is not None:
retString = str(self.expr)
else:
retString = "None"
self.__class__ = Forward
return "Forward: "+retString

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 )

class Upcase(TokenConverter):
"""Converter to upper case all matching tokens."""
def postParse( self, instring, loc, tokenlist ):
return map( string.upper, 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.skipWhitespace = True
self.joinString = joinString

def postParse( self, instring, loc, tokenlist ):
retToks = tokenlist.copy()
del retToks[:]
retToks += ParseResults([ self.joinString.join(tokenlist._asStringList()) ], 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.saveList = 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.saveList = True

def postParse( self, instring, loc, tokenlist ):
for i,tok in enumerate(tokenlist):
ikey = str(tok[0]).strip()
if len(tok)==1:
tokenlist[ikey] = ("",i)
elif len(tok)==2:
tokenlist[ikey] = (tok[1],i)
else:
dictvalue = tok.copy() #ParseResults(i)
del dictvalue[0]
tokenlist[ikey] = (dictvalue,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

#
# 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.
"""
if combine:
return Combine( expr + ZeroOrMore( Literal(delim) + expr ) ).setName(str(expr)+delim+"...")
else:
return ( expr + ZeroOrMore( Suppress( Literal(delim) ) + expr ) ).setName(str(expr)+delim+"...")

def oneOf( strs, caseless=False ):
"""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.
"""
if caseless:
isequal = ( lambda a,b: a.upper() == b.upper() )
parseElementClass = CaselessLiteral
else:
isequal = ( lambda a,b: a == b )
parseElementClass = Literal

symbols = strs.split()
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 ( isequal(other[:len(cur)],cur) ):
del symbols[i+j+1]
symbols.insert(i,other)
cur = other
break
else:
i += 1

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 ) ) )

alphas = string.letters
nums = string.digits
alphanums = alphas + nums
printables = "".join( [ c for c in string.printable if c not in string.whitespace ] )
empty = Empty().setName("empty")

_bslash = "\\"
_escapables = "tnrfbacdeghijklmopqsuvwxyz" + _bslash
_octDigits = "01234567"
_escapedChar = ( Word( _bslash, _escapables, exact=2 ) |
Word( _bslash, _octDigits, min=2, max=4 ) )
_sglQuote = Literal("'")
_dblQuote = Literal('"')
dblQuotedString = Combine( _dblQuote + ZeroOrMore( CharsNotIn('\\"\n\r') | _escapedChar ) + _dblQuote ).streamline().setName("string enclosed in double quotes")
sglQuotedString = Combine( _sglQuote + ZeroOrMore( CharsNotIn("\\'\n\r") | _escapedChar ) + _sglQuote ).streamline().setName("string enclosed in single quotes")
quotedString = ( dblQuotedString | sglQuotedString ).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 = Combine( Literal("/*") +
ZeroOrMore( CharsNotIn("*") | ( "*" + ~Literal("/") ) ) +
Literal("*/") ).streamline().setName("cStyleComment enclosed in /* ... */")
htmlComment = Combine( Literal("<!--") + ZeroOrMore( CharsNotIn("-") |
(~Literal("-->") + Literal("-").leaveWhitespace() ) ) +
Literal("-->") ).streamline().setName("htmlComment enclosed in <!-- ... -->")
restOfLine = Optional( CharsNotIn( "\n\r" ), default="" ).setName("rest of line up to \\n").leaveWhitespace()
_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 = Upcase( delimitedList( ident, ".", combine=True ) )
columnNameList = Group( delimitedList( columnName ) )#.setName("columns")
tableName = Upcase( delimitedList( ident, ".", combine=True ) )
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 " )