antlr

Class PythonCodeGenerator


public class PythonCodeGenerator
extends CodeGenerator

Generate MyParser.java, MyLexer.java and MyParserTokenTypes.java

Field Summary

protected static String
NONUNIQUE
Special value used to mark duplicate in treeVariableMap
(package private) int
astVarNumber
static int
caseSizeThreshold
(package private) String
commonExtraArgs
(package private) String
commonExtraParams
(package private) String
commonLocalVars
(package private) String
currentASTResult
Tracks the rule or labeled subrule being generated.
(package private) RuleBlock
currentRule
Tracks the rule being generated.
(package private) Hashtable
declaredASTVariables
Used to keep track of which AST variables have been defined in a rule (except for the #rule_name and #rule_name_in var's
(package private) String
exceptionThrown
protected boolean
genAST
static String
initHeaderAction
(package private) String
labeledElementASTType
(package private) String
labeledElementInit
(package private) String
labeledElementType
(package private) String
lexerClassName
(package private) String
lt1Value
static String
mainHeaderAction
(package private) String
parserClassName
protected boolean
saveText
protected int
syntacticPredLevel
(package private) String
throwNoViable
(package private) Hashtable
treeVariableMap
Mapping between the ids used in the current alt, and the names of variables used to represent their AST values.
(package private) String
treeWalkerClassName

Fields inherited from class antlr.CodeGenerator

BITSET_OPTIMIZE_INIT_THRESHOLD, DEBUG_CODE_GENERATOR, DEFAULT_BITSET_TEST_THRESHOLD, DEFAULT_MAKE_SWITCH_THRESHOLD, TokenTypesFileExt, TokenTypesFileSuffix, analyzer, antlrTool, behavior, bitsetTestThreshold, bitsetsUsed, charFormatter, currentOutput, grammar, makeSwitchThreshold, tabs

Constructor Summary

PythonCodeGenerator()
Construct code generator base class

Method Summary

protected void
_printAction(String s)
Print an action without leading tabs, attempting to preserve the current indentation level for multi-line actions Ignored if string is null.
protected void
_printJavadoc(String s)
protected int
addSemPred(String predicate)
Adds a semantic predicate string to the sem pred vector These strings will be used to build an array of sem pred names when building a debugging parser.
protected void
checkCurrentOutputStream()
void
exitIfError()
protected String
extractIdOfAction(String s, int line, int column)
Get the identifier portion of an argument-action.
protected String
extractTypeOfAction(String s, int line, int column)
Get the type portion of an argument-action.
protected void
flushTokens()
void
gen()
Generate the parser, lexer, treeparser, and token types in Java
void
gen(ActionElement action)
Generate code for the given grammar element.
void
gen(AlternativeBlock blk)
Generate code for the given grammar element.
void
gen(BlockEndElement end)
Generate code for the given grammar element.
void
gen(CharLiteralElement atom)
Generate code for the given grammar element.
void
gen(CharRangeElement r)
Generate code for the given grammar element.
void
gen(LexerGrammar g)
Generate the lexer Java file
void
gen(OneOrMoreBlock blk)
Generate code for the given grammar element.
void
gen(ParserGrammar g)
Generate the parser Java file
void
gen(RuleRefElement rr)
Generate code for the given grammar element.
void
gen(StringLiteralElement atom)
Generate code for the given grammar element.
void
gen(TokenRangeElement r)
Generate code for the given grammar element.
void
gen(TokenRefElement atom)
Generate code for the given grammar element.
void
gen(TreeElement t)
Generate code for the given grammar element.
void
gen(TreeWalkerGrammar g)
Generate the tree-parser Java file
void
gen(WildcardElement wc)
Generate code for the given grammar element.
void
gen(ZeroOrMoreBlock blk)
Generate code for the given grammar element.
protected void
genASTDeclaration(AlternativeElement el)
protected void
genASTDeclaration(AlternativeElement el, String node_type)
protected void
genASTDeclaration(AlternativeElement el, String var_name, String node_type)
protected void
genAlt(Alternative alt, AlternativeBlock blk)
Generate an alternative.
protected void
genBitsets(Vector bitsetList, int maxVocabulary)
Generate all the bitsets to be used in the parser or lexer Generate the raw bitset data like "long _tokenSet1_data[] = {...}" and the BitSet object declarations like "BitSet _tokenSet1 = new BitSet(_tokenSet1_data)" Note that most languages do not support object initialization inside a class definition, so other code-generators may have to separate the bitset declarations from the initializations (e.g., put the initializations in the generated constructor instead).
protected void
genBlockInitAction(AlternativeBlock blk)
Generate the init action for a block, which may be a RuleBlock or a plain AlternativeBLock.
protected void
genBlockPreamble(AlternativeBlock blk)
Generate the header for a block, which may be a RuleBlock or a plain AlternativeBLock.
protected void
genCases(BitSet p)
Generate a series of case statements that implement a BitSet test.
PythonBlockFinishingInfo
genCommonBlock(AlternativeBlock blk, boolean noTestForSingle)
Generate common code for a block of alternatives; return a postscript that needs to be generated at the end of the block.
protected void
genHeader()
Generate a header that is common to all Python files
protected void
genHeaderInit(Grammar grammar)
protected void
genHeaderMain(Grammar grammar)
protected void
genJavadocComment(Grammar g)
protected void
genJavadocComment(RuleSymbol g)
protected void
genLexerTest()
Generate an automated test for Python CharScanner (sub)classes.
protected void
genMatch(GrammarAtom atom)
protected void
genMatch(BitSet b)
protected void
genMatchUsingAtomText(GrammarAtom atom)
protected void
genMatchUsingAtomTokenType(GrammarAtom atom)
void
genNextToken()
Generate the nextToken() rule.
void
genRule(RuleSymbol s, boolean startSymbol, int ruleNum)
Gen a named rule block.
protected void
genSemPred(String pred, int line)
protected void
genSemPredMap()
Write an array of Strings which are the semantic predicate expressions.
protected void
genSynPred(SynPredBlock blk, String lookaheadExpr)
protected void
genTokenASTNodeMap()
Create and set Integer token type objects that map to Java Class objects (which AST node to create).
void
genTokenStrings()
Generate a static array containing the names of the tokens, indexed by the token type values.
protected void
genTokenTypes(TokenManager tm)
Generate the token types Java file
String
getASTCreateString(String astCtorArgs)
Get a string for an expression to generate creating of an AST node.
String
getASTCreateString(GrammarAtom atom, String astCtorArgs)
Get a string for an expression to generate creating of an AST node
String
getASTCreateString(Vector v)
Get a string for an expression to generate creation of an AST subtree.
protected String
getLookaheadTestExpression(Alternative alt, int maxDepth)
Generate a lookahead test expression for an alternate.
protected String
getLookaheadTestExpression(Lookahead look, int k)
protected String
getLookaheadTestTerm(int k, BitSet p)
Generate a depth==1 lookahead test expression given the BitSet.
String
getRangeExpression(int k, int[] elems)
Return an expression for testing a contiguous renage of elements
(package private) static boolean
isEmpty(String s)
protected boolean
isspace(char c)
protected boolean
lookaheadIsEmpty(Alternative alt, int maxDepth)
Is the lookahead for this alt empty?
String
mapTreeId(String idParam, ActionTransInfo transInfo)
Map an identifier to it's corresponding tree-node variable.
protected void
od(String s, int i, int end, String msg)
protected void
printAction(String s)
Print an action with leading tabs, attempting to preserve the current indentation level for multi-line actions Ignored if string is null.
protected void
printActionCode(String actionStr, int line)
protected void
printGrammarAction(Grammar grammar)
protected void
printMainFunc(String s)
protected void
printTabs()
Create a Java code-generator using the given Grammar.
protected String
processActionCode(String actionStr, int line)
protected String
processActionForSpecialSymbols(String actionStr, int line, RuleBlock currentRule, ActionTransInfo tInfo)
Lexically process $var and tree-specifiers in the action.
void
setupOutput(String className)
This method exists so a subclass, namely VAJCodeGenerator, can open the file in its own evil way.
(package private) String
toString(boolean v)

Methods inherited from class antlr.CodeGenerator

_print, _printAction, _println, decodeLexerRuleName, elementsAreRange, encodeLexerRuleName, extractIdOfAction, extractIdOfAction, extractTypeOfAction, extractTypeOfAction, gen, gen, gen, gen, gen, gen, gen, gen, gen, gen, gen, gen, gen, gen, gen, gen, gen, genTokenInterchange, getASTCreateString, getASTCreateString, getBitsetName, getFIRSTBitSet, getFOLLOWBitSet, mapTreeId, markBitsetForGen, print, printAction, printTabs, println, processActionForSpecialSymbols, processStringForASTConstructor, removeAssignmentFromDeclaration, reverseLexerRuleName, setAnalyzer, setBehavior, setGrammar, setTool

Field Details

NONUNIQUE

protected static final String NONUNIQUE
Special value used to mark duplicate in treeVariableMap


astVarNumber

(package private)  int astVarNumber


caseSizeThreshold

public static final int caseSizeThreshold

Field Value:
127


commonExtraArgs

(package private)  String commonExtraArgs


commonExtraParams

(package private)  String commonExtraParams


commonLocalVars

(package private)  String commonLocalVars


currentASTResult

(package private)  String currentASTResult
Tracks the rule or labeled subrule being generated. Used for AST generation.


currentRule

(package private)  RuleBlock currentRule
Tracks the rule being generated. Used for mapTreeId


declaredASTVariables

(package private)  Hashtable declaredASTVariables
Used to keep track of which AST variables have been defined in a rule (except for the #rule_name and #rule_name_in var's


exceptionThrown

(package private)  String exceptionThrown


genAST

protected boolean genAST


initHeaderAction

public static final String initHeaderAction


labeledElementASTType

(package private)  String labeledElementASTType


labeledElementInit

(package private)  String labeledElementInit


labeledElementType

(package private)  String labeledElementType


lexerClassName

(package private)  String lexerClassName


lt1Value

(package private)  String lt1Value


mainHeaderAction

public static final String mainHeaderAction


parserClassName

(package private)  String parserClassName


saveText

protected boolean saveText


syntacticPredLevel

protected int syntacticPredLevel


throwNoViable

(package private)  String throwNoViable


treeVariableMap

(package private)  Hashtable treeVariableMap
Mapping between the ids used in the current alt, and the names of variables used to represent their AST values.


treeWalkerClassName

(package private)  String treeWalkerClassName

Constructor Details

PythonCodeGenerator

public PythonCodeGenerator()
Construct code generator base class

Method Details

_printAction

protected void _printAction(String s)
Print an action without leading tabs, attempting to preserve the current indentation level for multi-line actions Ignored if string is null.
Overrides:
_printAction in interface CodeGenerator

Parameters:
s - The action string to output


_printJavadoc

protected void _printJavadoc(String s)


addSemPred

protected int addSemPred(String predicate)
Adds a semantic predicate string to the sem pred vector These strings will be used to build an array of sem pred names when building a debugging parser. This method should only be called when the debug option is specified


checkCurrentOutputStream

protected void checkCurrentOutputStream()


exitIfError

public void exitIfError()


extractIdOfAction

protected String extractIdOfAction(String s,
                                   int line,
                                   int column)
Get the identifier portion of an argument-action. For Python the ID of an action is assumed to be everything before the assignment, as Python does not support a type.
Overrides:
extractIdOfAction in interface CodeGenerator

Parameters:
s - The action text
line - Line used for error reporting.
column - Line used for error reporting.

Returns:
A string containing the text of the identifier


extractTypeOfAction

protected String extractTypeOfAction(String s,
                                     int line,
                                     int column)
Get the type portion of an argument-action. Python does not have a type declaration before an identifier, so we just return the empty string.
Overrides:
extractTypeOfAction in interface CodeGenerator

Parameters:
s - The action text
line - Line used for error reporting.

Returns:
A string containing the text of the type


flushTokens

protected void flushTokens()


gen

public void gen()
Generate the parser, lexer, treeparser, and token types in Java
Overrides:
gen in interface CodeGenerator


gen

public void gen(ActionElement action)
Generate code for the given grammar element.
Overrides:
gen in interface CodeGenerator

Parameters:


gen

public void gen(AlternativeBlock blk)
Generate code for the given grammar element.
Overrides:
gen in interface CodeGenerator

Parameters:
blk - The "x|y|z|..." block to generate


gen

public void gen(BlockEndElement end)
Generate code for the given grammar element.
Overrides:
gen in interface CodeGenerator

Parameters:


gen

public void gen(CharLiteralElement atom)
Generate code for the given grammar element.
Overrides:
gen in interface CodeGenerator

Parameters:


gen

public void gen(CharRangeElement r)
Generate code for the given grammar element.
Overrides:
gen in interface CodeGenerator

Parameters:


gen

public void gen(LexerGrammar g)
            throws IOException
Generate the lexer Java file
Overrides:
gen in interface CodeGenerator


gen

public void gen(OneOrMoreBlock blk)
Generate code for the given grammar element.
Overrides:
gen in interface CodeGenerator

Parameters:
blk - The (...)+ block to generate


gen

public void gen(ParserGrammar g)
            throws IOException
Generate the parser Java file
Overrides:
gen in interface CodeGenerator


gen

public void gen(RuleRefElement rr)
Generate code for the given grammar element.
Overrides:
gen in interface CodeGenerator

Parameters:


gen

public void gen(StringLiteralElement atom)
Generate code for the given grammar element.
Overrides:
gen in interface CodeGenerator

Parameters:


gen

public void gen(TokenRangeElement r)
Generate code for the given grammar element.
Overrides:
gen in interface CodeGenerator

Parameters:


gen

public void gen(TokenRefElement atom)
Generate code for the given grammar element.
Overrides:
gen in interface CodeGenerator

Parameters:


gen

public void gen(TreeElement t)
Generate code for the given grammar element.
Overrides:
gen in interface CodeGenerator

Parameters:


gen

public void gen(TreeWalkerGrammar g)
            throws IOException
Generate the tree-parser Java file
Overrides:
gen in interface CodeGenerator


gen

public void gen(WildcardElement wc)
Generate code for the given grammar element.
Overrides:
gen in interface CodeGenerator

Parameters:
wc - The wildcard element to generate


gen

public void gen(ZeroOrMoreBlock blk)
Generate code for the given grammar element.
Overrides:
gen in interface CodeGenerator

Parameters:
blk - The (...)* block to generate


genASTDeclaration

protected void genASTDeclaration(AlternativeElement el)


genASTDeclaration

protected void genASTDeclaration(AlternativeElement el,
                                 String node_type)


genASTDeclaration

protected void genASTDeclaration(AlternativeElement el,
                                 String var_name,
                                 String node_type)


genAlt

protected void genAlt(Alternative alt,
                      AlternativeBlock blk)
Generate an alternative.

Parameters:
alt - The alternative to generate
blk - The block to which the alternative belongs


genBitsets

protected void genBitsets(Vector bitsetList,
                          int maxVocabulary)
Generate all the bitsets to be used in the parser or lexer Generate the raw bitset data like "long _tokenSet1_data[] = {...}" and the BitSet object declarations like "BitSet _tokenSet1 = new BitSet(_tokenSet1_data)" Note that most languages do not support object initialization inside a class definition, so other code-generators may have to separate the bitset declarations from the initializations (e.g., put the initializations in the generated constructor instead).

Parameters:
bitsetList - The list of bitsets to generate.
maxVocabulary - Ensure that each generated bitset can contain at least this value.


genBlockInitAction

protected void genBlockInitAction(AlternativeBlock blk)
Generate the init action for a block, which may be a RuleBlock or a plain AlternativeBLock.


genBlockPreamble

protected void genBlockPreamble(AlternativeBlock blk)
Generate the header for a block, which may be a RuleBlock or a plain AlternativeBLock. This generates any variable declarations and syntactic-predicate-testing variables.


genCases

protected void genCases(BitSet p)
Generate a series of case statements that implement a BitSet test.

Parameters:
p - The Bitset for which cases are to be generated


genCommonBlock

public PythonBlockFinishingInfo genCommonBlock(AlternativeBlock blk,
                                               boolean noTestForSingle)
Generate common code for a block of alternatives; return a postscript that needs to be generated at the end of the block. Other routines may append else-clauses and such for error checking before the postfix is generated. If the grammar is a lexer, then generate alternatives in an order where alternatives requiring deeper lookahead are generated first, and EOF in the lookahead set reduces the depth of the lookahead. @param blk The block to generate @param noTestForSingle If true, then it does not generate a test for a single alternative.


genHeader

protected void genHeader()
Generate a header that is common to all Python files


genHeaderInit

protected void genHeaderInit(Grammar grammar)


genHeaderMain

protected void genHeaderMain(Grammar grammar)


genJavadocComment

protected void genJavadocComment(Grammar g)


genJavadocComment

protected void genJavadocComment(RuleSymbol g)


genLexerTest

protected void genLexerTest()
Generate an automated test for Python CharScanner (sub)classes.


genMatch

protected void genMatch(GrammarAtom atom)


genMatch

protected void genMatch(BitSet b)


genMatchUsingAtomText

protected void genMatchUsingAtomText(GrammarAtom atom)


genMatchUsingAtomTokenType

protected void genMatchUsingAtomTokenType(GrammarAtom atom)


genNextToken

public void genNextToken()
Generate the nextToken() rule. nextToken() is a synthetic lexer rule that is the implicit OR of all user-defined lexer rules.


genRule

public void genRule(RuleSymbol s,
                    boolean startSymbol,
                    int ruleNum)
Gen a named rule block. ASTs are generated for each element of an alternative unless the rule or the alternative have a '!' modifier. If an alternative defeats the default tree construction, it must set _AST to the root of the returned AST. Each alternative that does automatic tree construction, builds up root and child list pointers in an ASTPair structure. A rule finishes by setting the returnAST variable from the ASTPair.

Parameters:
startSymbol - true if the rule is a start symbol (i.e., not referenced elsewhere)


genSemPred

protected void genSemPred(String pred,
                          int line)


genSemPredMap

protected void genSemPredMap()
Write an array of Strings which are the semantic predicate expressions. The debugger will reference them by number only


genSynPred

protected void genSynPred(SynPredBlock blk,
                          String lookaheadExpr)


genTokenASTNodeMap

protected void genTokenASTNodeMap()
Create and set Integer token type objects that map to Java Class objects (which AST node to create).


genTokenStrings

public void genTokenStrings()
Generate a static array containing the names of the tokens, indexed by the token type values. This static array is used to format error messages so that the token identifers or literal strings are displayed instead of the token numbers. If a lexical rule has a paraphrase, use it rather than the token label.


genTokenTypes

protected void genTokenTypes(TokenManager tm)
            throws IOException
Generate the token types Java file


getASTCreateString

public String getASTCreateString(String astCtorArgs)
Get a string for an expression to generate creating of an AST node. Parse the first (possibly only) argument looking for the token type. If the token type is a valid token symbol, ask for it's AST node type and add to the end if only 2 arguments. The forms are #[T], #[T,"t"], and as of 2.7.2 #[T,"t",ASTclassname].

Parameters:


getASTCreateString

public String getASTCreateString(GrammarAtom atom,
                                 String astCtorArgs)
Get a string for an expression to generate creating of an AST node
Overrides:
getASTCreateString in interface CodeGenerator

Parameters:
atom - The grammar node for which you are creating the node


getASTCreateString

public String getASTCreateString(Vector v)
Get a string for an expression to generate creation of an AST subtree.
Overrides:
getASTCreateString in interface CodeGenerator

Parameters:
v - A Vector of String, where each element is an expression in the target language yielding an AST node.


getLookaheadTestExpression

protected String getLookaheadTestExpression(Alternative alt,
                                            int maxDepth)
Generate a lookahead test expression for an alternate. This will be a series of tests joined by '&&' and enclosed by '()', the number of such tests being determined by the depth of the lookahead.


getLookaheadTestExpression

protected String getLookaheadTestExpression(Lookahead look,
                                            int k)


getLookaheadTestTerm

protected String getLookaheadTestTerm(int k,
                                      BitSet p)
Generate a depth==1 lookahead test expression given the BitSet. This may be one of: 1) a series of 'x==X||' tests 2) a range test using >= && <= where possible, 3) a bitset membership test for complex comparisons

Parameters:
k - The lookahead level
p - The lookahead set for level k


getRangeExpression

public String getRangeExpression(int k,
                                 int[] elems)
Return an expression for testing a contiguous renage of elements

Parameters:
k - The lookahead level
elems - The elements representing the set, usually from BitSet.toArray().

Returns:
String containing test expression.


isEmpty

(package private) static boolean isEmpty(String s)


isspace

protected boolean isspace(char c)


lookaheadIsEmpty

protected boolean lookaheadIsEmpty(Alternative alt,
                                   int maxDepth)
Is the lookahead for this alt empty?


mapTreeId

public String mapTreeId(String idParam,
                        ActionTransInfo transInfo)
Map an identifier to it's corresponding tree-node variable. This is context-sensitive, depending on the rule and alternative being generated
Overrides:
mapTreeId in interface CodeGenerator

Parameters:
idParam - The identifier name to map

Returns:
The mapped id (which may be the same as the input), or null if the mapping is invalid due to duplicates


od

protected void od(String s,
                  int i,
                  int end,
                  String msg)


printAction

protected void printAction(String s)
Print an action with leading tabs, attempting to preserve the current indentation level for multi-line actions Ignored if string is null.
Overrides:
printAction in interface CodeGenerator

Parameters:
s - The action string to output


printActionCode

protected void printActionCode(String actionStr,
                               int line)


printGrammarAction

protected void printGrammarAction(Grammar grammar)


printMainFunc

protected void printMainFunc(String s)


printTabs

protected void printTabs()
Create a Java code-generator using the given Grammar. The caller must still call setTool, setBehavior, and setAnalyzer before generating code.
Overrides:
printTabs in interface CodeGenerator


processActionCode

protected String processActionCode(String actionStr,
                                   int line)


processActionForSpecialSymbols

protected String processActionForSpecialSymbols(String actionStr,
                                                int line,
                                                RuleBlock currentRule,
                                                ActionTransInfo tInfo)
Lexically process $var and tree-specifiers in the action. This will replace #id and #(...) with the appropriate function calls and/or variables etc...
Overrides:
processActionForSpecialSymbols in interface CodeGenerator


setupOutput

public void setupOutput(String className)
            throws IOException
This method exists so a subclass, namely VAJCodeGenerator, can open the file in its own evil way. JavaCodeGenerator simply opens a text file...


toString

(package private)  String toString(boolean v)