python.stg

antlr最新版本V3源代码

/*
 [The "BSD licence"]
 Copyright (c) 2005-2006 Terence Parr
 All rights reserved.

 Redistribution and use in source and binary forms, with or without
 modification, are permitted provided that the following conditions
 are met:
 1. Redistributions of source code must retain the above copyright
    notice, this list of conditions and the following disclaimer.
 2. Redistributions in binary form must reproduce the above copyright
    notice, this list of conditions and the following disclaimer in the
    documentation and/or other materials provided with the distribution.
 3. The name of the author may not be used to endorse or promote products
    derived from this software without specific prior written permission.

 THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
 IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
 INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/

/* in sync with Java/Java.stg revision 107 */

group Python implements ANTLRCore;

/** The overall file structure of a recognizer; stores methods for rules
 *  and cyclic DFAs plus support code.
 */
outputFile(LEXER,PARSER,TREE_PARSER, actionScope, actions,
           docComment, recognizer,
           name, tokens, tokenNames, rules, cyclicDFAs,
           bitsets, buildTemplate, buildAST, rewrite, profile,
           backtracking, synpreds, memoize, numRules,
           fileName, ANTLRVersion, generatedTimestamp, trace,
           scopes, superClass, literals) ::=
<<
# $ANTLR <ANTLRVersion> <fileName> <generatedTimestamp>

<@imports>
from antlr3 import *
<if(TREE_PARSER)>
from antlr3.tree import *<\n>
<endif>
from antlr3.compat import set, frozenset
<@end>

<actions.(actionScope).header>

<! <docComment> !>

# for convenience in actions
HIDDEN = BaseRecognizer.HIDDEN

# token types
<tokens:{<it.name>=<it.type>}; separator="\n">

<recognizer>
>>

lexer(grammar, name, tokens, scopes, rules, numRules, labelType="Token",
      filterMode) ::= <<
class <name>(Lexer):
    <scopes:{<if(it.isDynamicGlobalScope)><globalAttributeScope(scope=it)><endif>}>

    grammarFileName = "<fileName>"

    def __init__(self, input=None):
        Lexer.__init__(self, input)
<if(backtracking)>
        self.ruleMemo = {}
<endif>

        <cyclicDFAs:{dfa | <cyclicDFAInit(dfa)>}; seperator="\n">

        <actions.lexer.init>


    <actions.lexer.members>


<if(filterMode)>
    <filteringNextToken()>
<endif>
    <rules; separator="\n\n">

    <synpreds:{p | <lexerSynpred(p)>}>

    <cyclicDFAs:cyclicDFA()> <! dump tables for all DFA !>


>>

/** A override of Lexer.nextToken() that backtracks over mTokens() looking
 *  for matches.  No error can be generated upon error; just rewind, consume
 *  a token and then try again.  backtracking needs to be set as well.
 *  Make rule memoization happen only at levels above 1 as we start mTokens
 *  at backtracking==1.
 */
filteringNextToken() ::= <<
def nextToken(self):
    while True:
        if self.input.LA(1) == EOF:
            return EOF_TOKEN

        self.token = None
        self.channel = DEFAULT_CHANNEL
        self.tokenStartCharIndex = self.input.index()
        self.tokenStartCharPositionInLine = self.input.charPositionInLine
        self.tokenStartLine = self.input.line
        self._text = None
        try:
            m = self.input.mark()
            self.backtracking = 1 <! means we won't throw slow exception !>
            self.failed = False
            self.mTokens()
            self.backtracking = 0

            <! mTokens backtracks with synpred at backtracking==2
               and we set the synpredgate to allow actions at level 1. !>
            if self.failed:
                self.input.rewind(m)
                self.input.consume() <! advance one char and try again !>

            else:
                self.emit()
                return self.token

        except RecognitionException, re:
            # shouldn't happen in backtracking mode, but...
            self.reportError(re)
            self.recover(re)


def memoize(self, input, ruleIndex, ruleStartIndex):
    if self.backtracking > 1:
        # is Lexer always superclass?
        Lexer.memoize(self, input, ruleIndex, ruleStartIndex)


def alreadyParsedRule(self, input, ruleIndex):
    if self.backtracking > 1:
        return Lexer.alreadyParsedRule(self, input, ruleIndex)
    return False


>>

filteringActionGate() ::= "self.backtracking == 1"

/** How to generate a parser */

genericParser(grammar, name, scopes, tokens, tokenNames, rules, numRules,
              bitsets, inputStreamType, superClass,
              ASTLabelType="Object", labelType, members) ::= <<
# token names
tokenNames = [
    "\<invalid>", "\<EOR>", "\<DOWN>", "\<UP>", 
    <tokenNames; wrap, separator=", ">
]

<scopes:{<if(it.isDynamicGlobalScope)><globalAttributeScopeClass(scope=it)><endif>}>

<rules:{<ruleAttributeScopeClass(scope=it.ruleDescriptor.ruleScope)>}>

class <name>(<superClass>):
    grammarFileName = "<fileName>"
    tokenNames = tokenNames

    def __init__(self, input):
        <superClass>.__init__(self, input)
<if(backtracking)>
        self.ruleMemo = {}
<endif>

        <cyclicDFAs:{dfa | <cyclicDFAInit(dfa)>}; seperator="\n">

        <scopes:{<if(it.isDynamicGlobalScope)><globalAttributeScopeStack(scope=it)><endif>}>
	<rules:{<ruleAttributeScopeStack(scope=it.ruleDescriptor.ruleScope)>}>

        <actions.parser.init>

        <@members>
        <@end>


    <members>

    <rules; separator="\n\n">

    <synpreds:{p | <synpred(p)>}>

    <cyclicDFAs:cyclicDFA()> <! dump tables for all DFA !>

    <bitsets:{FOLLOW_<it.name>_in_<it.inName><it.tokenIndex> = frozenset([<it.tokenTypes:{<it>};separator=", ">])<\n>}>

>>

parser(grammar, name, scopes, tokens, tokenNames, rules, numRules, bitsets, ASTLabelType, superClass="Parser", labelType="Token", members={<actions.parser.members>}) ::= <<
<genericParser(inputStreamType="TokenStream", ...)>
>>

/** How to generate a tree parser; same as parser except the input
 *  stream is a different type.
 */
treeParser(grammar, name, scopes, tokens, tokenNames, globalAction, rules, numRules, bitsets, labelType={<ASTLabelType>}, ASTLabelType="Object", superClass="TreeParser", members={<actions.treeparser.members>}) ::= <<
<genericParser(inputStreamType="TreeNodeStream", ...)>
>>

/** A simpler version of a rule template that is specific to the imaginary
 *  rules created for syntactic predicates.  As they never have return values
 *  nor parameters etc..., just give simplest possible method.  Don't do
 *  any of the normal memoization stuff in here either; it's a waste.
 *  As predicates cannot be inlined into the invoking rule, they need to
 *  be in a rule by themselves.
 */
synpredRule(ruleName, ruleDescriptor, block, description, nakedBlock) ::=
<<
# $ANTLR start <ruleName>
def <ruleName>_fragment(self, <ruleDescriptor.parameterScope:parameterScope(scope=it)>):
<if(trace)>
    self.traceIn("<ruleName>_fragment", <ruleDescriptor.index>)
    try:
        <block>

    finally:
        self.traceOut("<ruleName>_fragment", <ruleDescriptor.index>)

<else>
    <block>
<endif>
# $ANTLR end <ruleName>


>>

synpred(name) ::= <<
def <name>(self):
    self.backtracking += 1
    <@start()>
    start = self.input.mark()
    self.<name>_fragment()
    success = not self.failed
    self.input.rewind(start)
    <@stop()>
    self.backtracking -= 1
    self.failed = False
    return success


>>

lexerSynpred(name) ::= <<
<synpred(name)>
>>

ruleMemoization(name) ::= <<
<if(memoize)>
if self.backtracking > 0 and self.alreadyParsedRule(self.input, <ruleDescriptor.index>):
    return <ruleReturnValue()>

<endif>
>>

/** How to test for failure and return from rule */
checkRuleBacktrackFailure() ::= <<
<if(backtracking)>
if self.failed:
    return <ruleReturnValue()>
<endif>
>>

/** This rule has failed, exit indicating failure during backtrack */
ruleBacktrackFailure() ::= <<
<if(backtracking)>
if self.backtracking > 0:
    self.failed = True
    return <ruleReturnValue()><\n>
<endif>
>>

/** How to generate code for a rule.  This includes any return type
 *  data aggregates required for multiple return values.
 */
rule(ruleName,ruleDescriptor,block,emptyRule,description,exceptions,finally,memoize) ::= <<
<returnScope(scope=ruleDescriptor.returnScope)>

# $ANTLR start <ruleName>
# <fileName>:<description>
def <ruleName>(self, <ruleDescriptor.parameterScope:parameterScope(scope=it)>):
<if(trace)>
    self.traceIn("<ruleName>", <ruleDescriptor.index>)<\n>
<endif>
    <ruleScopeSetUp()>
    <ruleDeclarations()>
    <ruleLabelDefs()>
    <ruleDescriptor.actions.init>
    <@preamble()>
    try:
        try:
            <ruleMemoization(name=ruleName)>
            <block>
            <ruleCleanUp()>
            <(ruleDescriptor.actions.after):execAction()>

<if(exceptions)>
        <exceptions:{e|<catch(decl=e.decl,action=e.action)><\n>}>
<else>
<if(!emptyRule)>
<if(actions.(actionScope).rulecatch)>
        <actions.(actionScope).rulecatch>
<else>
        except RecognitionException, re:
            self.reportError(re)
            self.recover(self.input, re)

<endif>
<else>
        finally:
            pass

<endif>
<endif>
    finally:
<if(trace)>
        self.traceOut("<ruleName>", <ruleDescriptor.index>)<\n>
<endif>
        <memoize()>
        <ruleScopeCleanUp()>
        <finally>
        pass

    <@postamble()>
    return <ruleReturnValue()>

# $ANTLR end <ruleName>
>>

catch(decl,action) ::= <<
except <e.decl>:
    <e.action>

>>

ruleDeclarations() ::= <<
<if(ruleDescriptor.hasMultipleReturnValues)>
retval = self.<ruleDescriptor.name>_return()
retval.start = self.input.LT(1)<\n>
<else>
<ruleDescriptor.returnScope.attributes:{ a |
<a.name> = <if(a.initValue)><a.initValue><else>None<endif>
}>
<endif>
<if(memoize)>
<ruleDescriptor.name>_StartIndex = self.input.index()
<endif>
>>

ruleScopeSetUp() ::= <<
<ruleDescriptor.useScopes:{self.<it>_stack.append(<it>_scope())}; separator="\n">
<ruleDescriptor.ruleScope:{self.<it.name>_stack.append(<it.name>_scope())}; separator="\n">
>>

ruleScopeCleanUp() ::= <<
<ruleDescriptor.useScopes:{self.<it>_stack.pop()}; separator="\n">
<ruleDescriptor.ruleScope:{self.<it.name>_stack.pop()}; separator="\n">
>>

ruleLabelDefs() ::= <<
<[ruleDescriptor.tokenLabels,ruleDescriptor.tokenListLabels]
    :{<it.label.text> = None}; separator="\n"
>
<[ruleDescriptor.tokenListLabels,ruleDescriptor.ruleListLabels]
    :{list_<it.label.text> = None}; separator="\n"
>
<[ruleDescriptor.ruleLabels,ruleDescriptor.ruleListLabels]
    :ruleLabelDef(label=it); separator="\n"
>
<ruleDescriptor.ruleListLabels:{<it.label.text> = None}; separator="\n">
>>

lexerRuleLabelDefs() ::= <<
<[ruleDescriptor.tokenLabels,
  ruleDescriptor.tokenListLabels,
  ruleDescriptor.ruleLabels]
    :{<it.label.text> = None}; separator="\n"
>
<ruleDescriptor.charLabels:{<it.label.text> = None}; separator="\n">
<[ruleDescriptor.tokenListLabels,
  ruleDescriptor.ruleListLabels,
  ruleDescriptor.ruleListLabels]
    :{list_<it.label.text> = None}; separator="\n"
>
>>

ruleReturnValue() ::= <<
<if(!ruleDescriptor.isSynPred)>
<if(ruleDescriptor.hasReturnValue)>
<if(ruleDescriptor.hasSingleReturnValue)>
<ruleDescriptor.singleValueReturnName>
<else>
retval
<endif>
<endif>
<endif>
>>

ruleCleanUp() ::= <<
<if(ruleDescriptor.hasMultipleReturnValues)>
<if(!TREE_PARSER)>
retval.stop = self.input.LT(-1)<\n>
<endif>
<endif>
>>

memoize() ::= <<
<if(memoize)>
<if(backtracking)>
if self.backtracking > 0:
    self.memoize(self.input, <ruleDescriptor.index>, <ruleDescriptor.name>_StartIndex)