Improve python3 performance via addition of __slots__

runtime/Python3/src/antlr4/BufferedTokenStream.py

@@ -27,6 +27,7 @@ class TokenStream(object):
 
 
 class BufferedTokenStream(TokenStream):
+    __slots__ = ('tokenSource', 'tokens', 'index', 'fetchedEOF')
 
     def __init__(self, tokenSource:Lexer):
         # The {@link TokenSource} from which tokens for this stream are fetched.

runtime/Python3/src/antlr4/CommonTokenFactory.py

@@ -15,6 +15,8 @@ class TokenFactory(object):
     pass
 
 class CommonTokenFactory(TokenFactory):
+    __slots__ = 'copyText'
+
     #
     # The default {@link CommonTokenFactory} instance.
     #
@@ -56,4 +58,4 @@ class CommonTokenFactory(TokenFactory):
         t.text = text
         return t
 
-CommonTokenFactory.DEFAULT = CommonTokenFactory()
+CommonTokenFactory.DEFAULT = CommonTokenFactory()

runtime/Python3/src/antlr4/CommonTokenStream.py

@@ -35,6 +35,7 @@ from antlr4.Token import Token
 
 
 class CommonTokenStream(BufferedTokenStream):
+    __slots__ = 'channel'
 
     def __init__(self, lexer:Lexer, channel:int=Token.DEFAULT_CHANNEL):
         super().__init__(lexer)

runtime/Python3/src/antlr4/FileStream.py

@@ -14,6 +14,7 @@ from antlr4.InputStream import InputStream
 
 
 class FileStream(InputStream):
+    __slots__ = 'fileName'
 
     def __init__(self, fileName:str, encoding:str='ascii', errors:str='strict'):
         super().__init__(self.readDataFrom(fileName, encoding, errors))

runtime/Python3/src/antlr4/InputStream.py

@@ -12,6 +12,7 @@ from antlr4.Token import Token
 
 
 class InputStream (object):
+    __slots__ = ('name', 'strdata', '_index', 'data', '_size')
 
     def __init__(self, data: str):
         self.name = "<empty>"

runtime/Python3/src/antlr4/IntervalSet.py

@@ -11,6 +11,7 @@ from antlr4.Token import Token
 IntervalSet = None
 
 class IntervalSet(object):
+    __slots__ = ('intervals', 'readOnly')
 
     def __init__(self):
         self.intervals = None

runtime/Python3/src/antlr4/LL1Analyzer.py

@@ -14,6 +14,7 @@ from antlr4.atn.Transition import WildcardTransition, NotSetTransition, Abstract
 
 
 class LL1Analyzer (object):
+    __slots__ = 'atn'
 
     #* Special value added to the lookahead sets to indicate that we hit
     #  a predicate during analysis if {@code seeThruPreds==false}.

runtime/Python3/src/antlr4/Lexer.py

@@ -28,6 +28,11 @@ class TokenSource(object):
 
 
 class Lexer(Recognizer, TokenSource):
+    __slots__ = (
+        '_input', '_output', '_factory', '_tokenFactorySourcePair', '_token',
+        '_tokenStartCharIndex', '_tokenStartLine', '_tokenStartColumn',
+        '_hitEOF', '_channel', '_type', '_modeStack', '_mode', '_text'
+    )
 
     DEFAULT_MODE = 0
     MORE = -2
@@ -322,4 +327,3 @@ class Lexer(Recognizer, TokenSource):
             else:
                 # TODO: Do we lose character or line position information?
                 self._input.consume()
-

runtime/Python3/src/antlr4/ListTokenSource.py

@@ -18,6 +18,7 @@ from antlr4.Token import Token
 
 
 class ListTokenSource(TokenSource):
+    __slots__ = ('tokens', 'sourceName', 'pos', 'eofToken', '_factory')
 
     # Constructs a new {@link ListTokenSource} instance from the specified
     # collection of {@link Token} objects and source name.
@@ -140,4 +141,4 @@ class ListTokenSource(TokenSource):
         if inputStream is not None:
             return inputStream.getSourceName()
         else:
-            return "List"
+            return "List"

runtime/Python3/src/antlr4/Parser.py

@@ -23,6 +23,7 @@ from antlr4.tree.ParseTreePatternMatcher import ParseTreePatternMatcher
 from antlr4.tree.Tree import ParseTreeListener, TerminalNode, ErrorNode
 
 class TraceListener(ParseTreeListener):
+    __slots__ = '_parser'
 
     def __init__(self, parser):
         self._parser = parser
@@ -44,7 +45,11 @@ class TraceListener(ParseTreeListener):
 
 # self is all the parsing support code essentially; most of it is error recovery stuff.#
 class Parser (Recognizer):
+    __slots__ = (
+        '_input', '_output', '_errHandler', '_precedenceStack', '_ctx',
+        'buildParseTrees', '_tracer', '_parseListeners', '_syntaxErrors'
 
+    )
     # self field maps from the serialized ATN string to the deserialized {@link ATN} with
     # bypass alternatives.
     #

runtime/Python3/src/antlr4/ParserInterpreter.py

@@ -32,6 +32,11 @@ from antlr4.error.Errors import RecognitionException, UnsupportedOperationExcept
 
 
 class ParserInterpreter(Parser):
+    __slots__ = (
+        'grammarFileName', 'atn', 'tokenNames', 'ruleNames', 'decisionToDFA',
+        'sharedContextCache', '_parentContextStack',
+        'pushRecursionContextStates'
+    )
 
     def __init__(self, grammarFileName:str, tokenNames:list, ruleNames:list, atn:ATN, input:TokenStream):
         super().__init__(input)

runtime/Python3/src/antlr4/ParserRuleContext.py

@@ -34,7 +34,7 @@ from antlr4.tree.Tree import ParseTreeListener, ParseTree, TerminalNodeImpl, Err
 ParserRuleContext = None
 
 class ParserRuleContext(RuleContext):
-
+    __slots__ = ('children', 'start', 'stop', 'exception')
     def __init__(self, parent:ParserRuleContext = None, invokingStateNumber:int = None ):
         super().__init__(parent, invokingStateNumber)
         #* If we are debugging or building a parse tree for a visitor,

runtime/Python3/src/antlr4/Recognizer.py

@@ -11,6 +11,7 @@ from antlr4.error.ErrorListener import ProxyErrorListener, ConsoleErrorListener
 RecognitionException = None
 
 class Recognizer(object):
+    __slots__ = ('_listeners', '_interp', '_stateNumber')
 
     tokenTypeMapCache = dict()
     ruleIndexMapCache = dict()

runtime/Python3/src/antlr4/RuleContext.py

@@ -33,7 +33,7 @@ RuleContext = None
 Parser = None
 
 class RuleContext(RuleNode):
-
+    __slots__ = ('parentCtx', 'invokingState')
     EMPTY = None
 
     def __init__(self, parent:RuleContext=None, invokingState:int=-1):
@@ -225,4 +225,3 @@ class RuleContext(RuleNode):
 
             buf.write("]")
             return buf.getvalue()
-

runtime/Python3/src/antlr4/Token.py

@@ -10,6 +10,7 @@ from io import StringIO
 
 
 class Token (object):
+    __slots__ = ('source', 'type', 'channel', 'start', 'stop', 'tokenIndex', 'line', 'column', '_text')
 
     INVALID_TYPE = 0
 
@@ -68,7 +69,6 @@ class Token (object):
 
 class CommonToken(Token):
 
-
     # An empty {@link Pair} which is used as the default value of
     # {@link #source} for tokens that do not have a source.
     EMPTY_SOURCE = (None, None)

runtime/Python3/src/antlr4/TokenStreamRewriter.py

@@ -11,6 +11,8 @@ from antlr4.CommonTokenStream import CommonTokenStream
 
 
 class TokenStreamRewriter(object):
+    __slots__ = ('tokens', 'programs', 'lastRewriteTokenIndexes')
+
     DEFAULT_PROGRAM_NAME = "default"
     PROGRAM_INIT_SIZE = 100
     MIN_TOKEN_INDEX = 0
@@ -99,7 +101,7 @@ class TokenStreamRewriter(object):
 
     def getProgram(self, program_name):
         return self.programs.setdefault(program_name, [])
-        
+
     def getDefaultText(self):
         return self.getText(self.DEFAULT_PROGRAM_NAME, 0, len(self.tokens.tokens) - 1)
 
@@ -195,6 +197,7 @@ class TokenStreamRewriter(object):
         return reduced
 
     class RewriteOperation(object):
+        __slots__ = ('tokens', 'index', 'text', 'instructionIndex')
 
         def __init__(self, tokens, index, text=""):
             """
@@ -233,8 +236,9 @@ class TokenStreamRewriter(object):
 
     class InsertAfterOp(InsertBeforeOp):
         pass
-            
+
     class ReplaceOp(RewriteOperation):
+        __slots__ = 'last_index'
 
         def __init__(self, from_idx, to_idx, tokens, text):
             super(TokenStreamRewriter.ReplaceOp, self).__init__(tokens, from_idx, text)
@@ -244,7 +248,7 @@ class TokenStreamRewriter(object):
             if self.text:
                 buf.write(self.text)
             return self.last_index + 1
-            
+
         def __str__(self):
             if self.text:
                 return '<ReplaceOp@{}..{}:"{}">'.format(self.tokens.get(self.index), self.tokens.get(self.last_index),

runtime/Python3/src/antlr4/atn/ATN.py

@@ -12,6 +12,11 @@ from antlr4.atn.ATNState import ATNState, DecisionState
 
 
 class ATN(object):
+    __slots__ = (
+        'grammarType', 'maxTokenType', 'states', 'decisionToState',
+        'ruleToStartState', 'ruleToStopState', 'modeNameToStartState',
+        'ruleToTokenType', 'lexerActions', 'modeToStartState'
+    )
 
     INVALID_ALT_NUMBER = 0
 
@@ -58,7 +63,7 @@ class ATN(object):
         if s.nextTokenWithinRule is not None:
             return s.nextTokenWithinRule
         s.nextTokenWithinRule = self.nextTokensInContext(s, None)
-        s.nextTokenWithinRule.readonly = True
+        s.nextTokenWithinRule.readOnly = True
         return s.nextTokenWithinRule
 
     def nextTokens(self, s:ATNState, ctx:RuleContext = None):
@@ -124,4 +129,4 @@ class ATN(object):
             ctx = ctx.parentCtx
         if Token.EPSILON in following:
             expected.addOne(Token.EOF)
-        return expected
+        return expected

runtime/Python3/src/antlr4/atn/ATNConfig.py

@@ -21,6 +21,10 @@ from antlr4.atn.SemanticContext import SemanticContext
 ATNConfig = None
 
 class ATNConfig(object):
+    __slots__ = (
+        'state', 'alt', 'context', 'semanticContext', 'reachesIntoOuterContext',
+        'precedenceFilterSuppressed'
+    )
 
     def __init__(self, state:ATNState=None, alt:int=None, context:PredictionContext=None, semantic:SemanticContext=None, config:ATNConfig=None):
         if config is not None:
@@ -110,6 +114,7 @@ class ATNConfig(object):
 LexerATNConfig = None
 
 class LexerATNConfig(ATNConfig):
+    __slots__ = ('lexerActionExecutor', 'passedThroughNonGreedyDecision')
 
     def __init__(self, state:ATNState, alt:int=None, context:PredictionContext=None, semantic:SemanticContext=SemanticContext.NONE,
                  lexerActionExecutor:LexerActionExecutor=None, config:LexerATNConfig=None):

runtime/Python3/src/antlr4/atn/ATNConfigSet.py

@@ -20,6 +20,12 @@ from antlr4.error.Errors import UnsupportedOperationException, IllegalStateExcep
 ATNSimulator = None
 
 class ATNConfigSet(object):
+    __slots__ = (
+        'configLookup', 'fullCtx', 'readonly', 'configs', 'uniqueAlt',
+        'conflictingAlts', 'hasSemanticContext', 'dipsIntoOuterContext',
+        'cachedHashCode'
+    )
+
     #
     # The reason that we need this is because we don't want the hash map to use
     # the standard hash code and equals. We need all configurations with the same
@@ -204,6 +210,3 @@ class OrderedATNConfigSet(ATNConfigSet):
 
     def __init__(self):
         super().__init__()
-
-
-

runtime/Python3/src/antlr4/atn/ATNDeserializationOptions.py

@@ -6,6 +6,7 @@
 ATNDeserializationOptions = None
 
 class ATNDeserializationOptions(object):
+    __slots__ = ('readOnly', 'verifyATN', 'generateRuleBypassTransitions')
 
     defaultOptions = None
 
@@ -21,4 +22,3 @@ class ATNDeserializationOptions(object):
 
 ATNDeserializationOptions.defaultOptions = ATNDeserializationOptions()
 ATNDeserializationOptions.defaultOptions.readOnly = True
-

runtime/Python3/src/antlr4/atn/ATNDeserializer.py

@@ -31,6 +31,7 @@ SERIALIZED_VERSION = 3
 SERIALIZED_UUID = ADDED_UNICODE_SMP
 
 class ATNDeserializer (object):
+    __slots__ = ('deserializationOptions', 'data', 'pos', 'uuid')
 
     def __init__(self, options : ATNDeserializationOptions = None):
         if options is None:

runtime/Python3/src/antlr4/atn/ATNSimulator.py

@@ -10,6 +10,7 @@ from antlr4.dfa.DFAState import DFAState
 
 
 class ATNSimulator(object):
+    __slots__ = ('atn', 'sharedContextCache', '__dict__')
 
     # Must distinguish between missing edge and edge we know leads nowhere#/
     ERROR = DFAState(configs=ATNConfigSet())
@@ -44,4 +45,3 @@ class ATNSimulator(object):
             return context
         visited = dict()
         return getCachedPredictionContext(context, self.sharedContextCache, visited)
-

runtime/Python3/src/antlr4/atn/ATNState.py

@@ -69,6 +69,10 @@ from antlr4.atn.Transition import Transition
 INITIAL_NUM_TRANSITIONS = 4
 
 class ATNState(object):
+    __slots__ = (
+        'atn', 'stateNumber', 'stateType', 'ruleIndex', 'epsilonOnlyTransitions',
+        'transitions', 'nextTokenWithinRule',
+    )
 
     # constants for serialization
     INVALID_TYPE = 0
@@ -148,7 +152,7 @@ class BasicState(ATNState):
 
 
 class DecisionState(ATNState):
-
+    __slots__ = ('decision', 'nonGreedy')
     def __init__(self):
         super().__init__()
         self.decision = -1
@@ -156,6 +160,7 @@ class DecisionState(ATNState):
 
 #  The start of a regular {@code (...)} block.
 class BlockStartState(DecisionState):
+    __slots__ = 'endState'
 
     def __init__(self):
         super().__init__()
@@ -169,6 +174,7 @@ class BasicBlockStartState(BlockStartState):
 
 # Terminal node of a simple {@code (a|b|c)} block.
 class BlockEndState(ATNState):
+    __slots__ = 'startState'
 
     def __init__(self):
         super().__init__()
@@ -187,6 +193,7 @@ class RuleStopState(ATNState):
         self.stateType = self.RULE_STOP
 
 class RuleStartState(ATNState):
+    __slots__ = ('stopState', 'isPrecedenceRule')
 
     def __init__(self):
         super().__init__()
@@ -209,6 +216,7 @@ class PlusLoopbackState(DecisionState):
 #  real decision-making note for {@code A+}.
 #
 class PlusBlockStartState(BlockStartState):
+    __slots__ = 'loopBackState'
 
     def __init__(self):
         super().__init__()
@@ -230,6 +238,7 @@ class StarLoopbackState(ATNState):
 
 
 class StarLoopEntryState(DecisionState):
+    __slots__ = ('loopBackState', 'isPrecedenceDecision')
 
     def __init__(self):
         super().__init__()
@@ -240,6 +249,7 @@ class StarLoopEntryState(DecisionState):
 
 # Mark the end of a * or + loop.
 class LoopEndState(ATNState):
+    __slots__ = 'loopBackState'
 
     def __init__(self):
         super().__init__()

runtime/Python3/src/antlr4/atn/LexerATNSimulator.py

@@ -34,6 +34,7 @@ from antlr4.dfa.DFAState import DFAState
 from antlr4.error.Errors import LexerNoViableAltException, UnsupportedOperationException
 
 class SimState(object):
+    __slots__ = ('index', 'line', 'column', 'dfaState')
 
     def __init__(self):
         self.reset()
@@ -49,6 +50,10 @@ Lexer = None
 LexerATNSimulator = None
 
 class LexerATNSimulator(ATNSimulator):
+    __slots__ = (
+        'decisionToDFA', 'recog', 'startIndex', 'line', 'column', 'mode',
+        'DEFAULT_MODE', 'MAX_CHAR_VALUE', 'prevAccept'
+    )
 
     debug = False
     dfa_debug = False
@@ -58,8 +63,6 @@ class LexerATNSimulator(ATNSimulator):
 
     ERROR = None
 
-    match_calls = 0
-
     def __init__(self, recog:Lexer, atn:ATN, decisionToDFA:list, sharedContextCache:PredictionContextCache):
         super().__init__(atn, sharedContextCache)
         self.decisionToDFA = decisionToDFA
@@ -89,7 +92,6 @@ class LexerATNSimulator(ATNSimulator):
         self.startIndex = simulator.startIndex
 
     def match(self, input:InputStream , mode:int):
-        self.match_calls += 1
         self.mode = mode
         mark = input.mark()
         try:
@@ -565,4 +567,4 @@ class LexerATNSimulator(ATNSimulator):
 
 LexerATNSimulator.ERROR = DFAState(0x7FFFFFFF, ATNConfigSet())
 
-del Lexer
+del Lexer

runtime/Python3/src/antlr4/atn/LexerAction.py

@@ -22,6 +22,7 @@ class LexerActionType(IntEnum):
     TYPE = 7        #The type of a {@link LexerTypeAction} action.
 
 class LexerAction(object):
+    __slots__ = ('actionType', 'isPositionDependent')
 
     def __init__(self, action:LexerActionType):
         self.actionType = action
@@ -39,7 +40,7 @@ class LexerAction(object):
 #
 # <p>The {@code skip} command does not have any parameters, so this action is
 # implemented as a singleton instance exposed by {@link #INSTANCE}.</p>
-class LexerSkipAction(LexerAction ):
+class LexerSkipAction(LexerAction):
 
     # Provides a singleton instance of this parameterless lexer action.
     INSTANCE = None
@@ -58,6 +59,7 @@ LexerSkipAction.INSTANCE = LexerSkipAction()
 #  Implements the {@code type} lexer action by calling {@link Lexer#setType}
 # with the assigned type.
 class LexerTypeAction(LexerAction):
+    __slots__ = 'type'
 
     def __init__(self, type:int):
         super().__init__(LexerActionType.TYPE)
@@ -84,6 +86,7 @@ class LexerTypeAction(LexerAction):
 # Implements the {@code pushMode} lexer action by calling
 # {@link Lexer#pushMode} with the assigned mode.
 class LexerPushModeAction(LexerAction):
+    __slots__ = 'mode'
 
     def __init__(self, mode:int):
         super().__init__(LexerActionType.PUSH_MODE)
@@ -152,6 +155,7 @@ LexerMoreAction.INSTANCE = LexerMoreAction()
 # Implements the {@code mode} lexer action by calling {@link Lexer#mode} with
 # the assigned mode.
 class LexerModeAction(LexerAction):
+    __slots__ = 'mode'
 
     def __init__(self, mode:int):
         super().__init__(LexerActionType.MODE)
@@ -186,6 +190,7 @@ class LexerModeAction(LexerAction):
 # command argument could not be evaluated when the grammar was compiled.</p>
 
 class LexerCustomAction(LexerAction):
+    __slots__ = ('ruleIndex', 'actionIndex')
 
     # Constructs a custom lexer action with the specified rule and action
     # indexes.
@@ -220,6 +225,7 @@ class LexerCustomAction(LexerAction):
 # Implements the {@code channel} lexer action by calling
 # {@link Lexer#setChannel} with the assigned channel.
 class LexerChannelAction(LexerAction):
+    __slots__ = 'channel'
 
     # Constructs a new {@code channel} action with the specified channel value.
     # @param channel The channel value to pass to {@link Lexer#setChannel}.
@@ -255,6 +261,7 @@ class LexerChannelAction(LexerAction):
 # lexer actions, see {@link LexerActionExecutor#append} and
 # {@link LexerActionExecutor#fixOffsetBeforeMatch}.</p>
 class LexerIndexedCustomAction(LexerAction):
+    __slots__ = ('offset', 'action')
 
     # Constructs a new indexed custom action by associating a character offset
     # with a {@link LexerAction}.

runtime/Python3/src/antlr4/atn/LexerActionExecutor.py

@@ -20,6 +20,7 @@ Lexer = None
 LexerActionExecutor = None
 
 class LexerActionExecutor(object):
+    __slots__ = ('lexerActions', 'hashCode')
 
     def __init__(self, lexerActions:list=list()):
         self.lexerActions = lexerActions
@@ -139,4 +140,4 @@ class LexerActionExecutor(object):
             return self.hashCode == other.hashCode \
                 and self.lexerActions == other.lexerActions
 
-del Lexer
+del Lexer

runtime/Python3/src/antlr4/atn/ParserATNSimulator.py

@@ -255,6 +255,10 @@ from antlr4.error.Errors import NoViableAltException
 
 
 class ParserATNSimulator(ATNSimulator):
+    __slots__ = (
+        'parser', 'decisionToDFA', 'predictionMode', '_input', '_startIndex',
+        '_outerContext', '_dfa', 'mergeCache'
+    )
 
     debug = False
     debug_list_atn_decisions = False
@@ -1643,4 +1647,3 @@ class ParserATNSimulator(ATNSimulator):
                                ", input=" + self.parser.getTokenStream().getText(startIndex, stopIndex))
         if self.parser is not None:
             self.parser.getErrorListenerDispatch().reportAmbiguity(self.parser, dfa, startIndex, stopIndex, exact, ambigAlts, configs)
-

runtime/Python3/src/antlr4/atn/SemanticContext.py

@@ -95,6 +95,7 @@ def filterPrecedencePredicates(collection:set):
 
 
 class Predicate(SemanticContext):
+    __slots__ = ('ruleIndex', 'predIndex', 'isCtxDependent')
 
     def __init__(self, ruleIndex:int=-1, predIndex:int=-1, isCtxDependent:bool=False):
         self.ruleIndex = ruleIndex
@@ -153,6 +154,7 @@ class PrecedencePredicate(SemanticContext):
 # is false.
 del AND
 class AND(SemanticContext):
+    __slots__ = 'opnds'
 
     def __init__(self, a:SemanticContext, b:SemanticContext):
         operands = set()
@@ -238,6 +240,7 @@ class AND(SemanticContext):
 # contexts is true.
 del OR
 class OR (SemanticContext):
+    __slots__ = 'opnds'
 
     def __init__(self, a:SemanticContext, b:SemanticContext):
         operands = set()
@@ -317,4 +320,4 @@ class OR (SemanticContext):
             return buf.getvalue()
 
 
-SemanticContext.NONE = Predicate()
+SemanticContext.NONE = Predicate()

runtime/Python3/src/antlr4/atn/Transition.py

@@ -26,6 +26,8 @@ ATNState = None
 RuleStartState = None
 
 class Transition (object):
+    __slots__ = ('target','isEpsilon','label')
+
     # constants for serialization
     EPSILON			= 1
     RANGE			= 2
@@ -66,6 +68,7 @@ class Transition (object):
 
 # TODO: make all transitions sets? no, should remove set edges
 class AtomTransition(Transition):
+    __slots__ = ('label_', 'serializationType')
 
     def __init__(self, target:ATNState, label:int):
         super().__init__(target)
@@ -85,6 +88,7 @@ class AtomTransition(Transition):
         return str(self.label_)
 
 class RuleTransition(Transition):
+    __slots__ = ('ruleIndex', 'precedence', 'followState', 'serializationType')
 
     def __init__(self, ruleStart:RuleStartState, ruleIndex:int, precedence:int, followState:ATNState):
         super().__init__(ruleStart)
@@ -99,6 +103,7 @@ class RuleTransition(Transition):
 
 
 class EpsilonTransition(Transition):
+    __slots__ = ('serializationType', 'outermostPrecedenceReturn')
 
     def __init__(self, target, outermostPrecedenceReturn=-1):
         super(EpsilonTransition, self).__init__(target)
@@ -113,6 +118,7 @@ class EpsilonTransition(Transition):
         return "epsilon"
 
 class RangeTransition(Transition):
+    __slots__ = ('serializationType', 'start', 'stop')
 
     def __init__(self, target:ATNState, start:int, stop:int):
         super().__init__(target)
@@ -139,6 +145,7 @@ class AbstractPredicateTransition(Transition):
 
 
 class PredicateTransition(AbstractPredicateTransition):
+    __slots__ = ('serializationType', 'ruleIndex', 'predIndex', 'isCtxDependent')
 
     def __init__(self, target:ATNState, ruleIndex:int, predIndex:int, isCtxDependent:bool):
         super().__init__(target)
@@ -158,6 +165,7 @@ class PredicateTransition(AbstractPredicateTransition):
         return "pred_" + str(self.ruleIndex) + ":" + str(self.predIndex)
 
 class ActionTransition(Transition):
+    __slots__ = ('serializationType', 'ruleIndex', 'actionIndex', 'isCtxDependent')
 
     def __init__(self, target:ATNState, ruleIndex:int, actionIndex:int=-1, isCtxDependent:bool=False):
         super().__init__(target)
@@ -175,6 +183,7 @@ class ActionTransition(Transition):
 
 # A transition containing a set of values.
 class SetTransition(Transition):
+    __slots__ = 'serializationType'
 
     def __init__(self, target:ATNState, set:IntervalSet):
         super().__init__(target)
@@ -207,6 +216,7 @@ class NotSetTransition(SetTransition):
 
 
 class WildcardTransition(Transition):
+    __slots__ = 'serializationType'
 
     def __init__(self, target:ATNState):
         super().__init__(target)
@@ -220,6 +230,7 @@ class WildcardTransition(Transition):
 
 
 class PrecedencePredicateTransition(AbstractPredicateTransition):
+    __slots__ = ('serializationType', 'precedence')
 
     def __init__(self, target:ATNState, precedence:int):
         super().__init__(target)
@@ -254,4 +265,4 @@ Transition.serializationTypes = {
 del ATNState
 del RuleStartState
 
-from antlr4.atn.ATNState import *
+from antlr4.atn.ATNState import *

runtime/Python3/src/antlr4/dfa/DFA.py

@@ -11,6 +11,7 @@ from antlr4.error.Errors import IllegalStateException
 
 
 class DFA(object):
+    __slots__ = ('atnStartState', 'decision', '_states', 's0', 'precedenceDfa')
 
     def __init__(self, atnStartState:DecisionState, decision:int=0):
         # From which ATN state did we create this DFA?
@@ -130,4 +131,3 @@ class DFA(object):
         from antlr4.dfa.DFASerializer import LexerDFASerializer
         serializer = LexerDFASerializer(self)
         return str(serializer)
-

runtime/Python3/src/antlr4/dfa/DFASerializer.py

@@ -12,6 +12,7 @@ from antlr4.dfa.DFAState import DFAState
 
 
 class DFASerializer(object):
+    __slots__ = ('dfa', 'literalNames', 'symbolicNames')
 
     def __init__(self, dfa:DFA, literalNames:list=None, symbolicNames:list=None):
         self.dfa = dfa

runtime/Python3/src/antlr4/dfa/DFAState.py

@@ -11,6 +11,8 @@ from antlr4.atn.SemanticContext import SemanticContext
 
 
 class PredPrediction(object):
+    __slots__ = ('alt', 'pred')
+
     def __init__(self, pred:SemanticContext, alt:int):
         self.alt = alt
         self.pred = pred
@@ -43,6 +45,10 @@ class PredPrediction(object):
 #  meaning that state was reached via a different set of rule invocations.</p>
 #/
 class DFAState(object):
+    __slots__ = (
+        'stateNumber', 'configs', 'edges', 'isAcceptState', 'prediction',
+        'lexerActionExecutor', 'requiresFullContext', 'predicates'
+    )
 
     def __init__(self, stateNumber:int=-1, configs:ATNConfigSet=ATNConfigSet()):
         self.stateNumber = stateNumber

runtime/Python3/src/antlr4/tree/Chunk.py

@@ -8,6 +8,7 @@ class Chunk(object):
     pass
 
 class TagChunk(Chunk):
+    __slots__ = ('tag', 'label')
 
     def __init__(self, tag:str, label:str=None):
         self.tag = tag
@@ -20,10 +21,10 @@ class TagChunk(Chunk):
             return self.label + ":" + self.tag
 
 class TextChunk(Chunk):
+    __slots__ = 'text'
 
     def __init__(self, text:str):
         self.text = text
 
     def __str__(self):
         return "'" + self.text + "'"
-

runtime/Python3/src/antlr4/tree/ParseTreeMatch.py

@@ -14,7 +14,7 @@ from antlr4.tree.Tree import ParseTree
 
 
 class ParseTreeMatch(object):
-
+    __slots__ = ('tree', 'pattern', 'labels', 'mismatchedNode')
     #
     # Constructs a new instance of {@link ParseTreeMatch} from the specified
     # parse tree and pattern.

runtime/Python3/src/antlr4/tree/ParseTreePattern.py

@@ -14,6 +14,7 @@ from antlr4.xpath.XPath import XPath
 
 
 class ParseTreePattern(object):
+    __slots__ = ('matcher', 'patternRuleIndex', 'pattern', 'patternTree')
 
     # Construct a new instance of the {@link ParseTreePattern} class.
     #

runtime/Python3/src/antlr4/tree/ParseTreePatternMatcher.py

@@ -89,6 +89,7 @@ class StartRuleDoesNotConsumeFullPattern(Exception):
 
 
 class ParseTreePatternMatcher(object):
+    __slots__ = ('lexer', 'parser', 'start', 'stop', 'escape')
 
     # Constructs a {@link ParseTreePatternMatcher} or from a {@link Lexer} and
     # {@link Parser} object. The lexer input stream is altered for tokenizing

runtime/Python3/src/antlr4/tree/RuleTagToken.py

@@ -13,7 +13,8 @@ from antlr4.Token import Token
 
 
 class RuleTagToken(Token):
-   #
+    __slots__ = ('label', 'ruleName')
+    #
     # Constructs a new instance of {@link RuleTagToken} with the specified rule
     # name, bypass token type, and label.
     #

runtime/Python3/src/antlr4/tree/TokenTagToken.py

@@ -13,7 +13,7 @@ from antlr4.Token import CommonToken
 
 
 class TokenTagToken(CommonToken):
-
+    __slots__ = ('tokenName', 'label')
     # Constructs a new instance of {@link TokenTagToken} with the specified
     # token name, type, and label.
     #

runtime/Python3/src/antlr4/tree/Tree.py

@@ -80,6 +80,7 @@ class ParseTreeListener(object):
 del ParserRuleContext
 
 class TerminalNodeImpl(TerminalNode):
+    __slots__ = ('parentCtx', 'symbol')
 
     def __init__(self, symbol:Token):
         self.parentCtx = None
@@ -187,4 +188,4 @@ class ParseTreeWalker(object):
         ctx.exitRule(listener)
         listener.exitEveryRule(ctx)
 
-ParseTreeWalker.DEFAULT = ParseTreeWalker()
+ParseTreeWalker.DEFAULT = ParseTreeWalker()

tool/resources/org/antlr/v4/tool/templates/codegen/Python3/Python3.stg

@@ -652,6 +652,7 @@ CaptureNextTokenType(d) ::= "<d.varName> = self._input.LA(1)"
 
 StructDecl(struct,ctorAttrs,attrs,getters,dispatchMethods,interfaces,extensionMembers) ::= <<
 class <struct.name>(<if(contextSuperClass)><contextSuperClass><else>ParserRuleContext<endif>):
+    __slots__ = 'parser'
 
     def __init__(self, parser, parent:ParserRuleContext=None, invokingState:int=-1<struct.ctorAttrs:{a | , <a.name><if(a.type)>:<a.type><endif>=None}>):
         super().__init__(parent, invokingState)