net.ognyanov.niogram.parser.antlr4

Class Antlr4ToAstParser

java.lang.Object

net.ognyanov.niogram.parser.antlr4.Antlr4ToAstParser

All Implemented Interfaces:

AstParser, ErrorDispatcher

public class Antlr4ToAstParser
extends Object
implements AstParser

The NioGram parser for ANTLR 4 grammars.

Parses grammar text into AST.

The general strategy of the parser is to try to produce an AST even if errors are encountered during parsing. It is up to the client to decide whether and for what purposes the result AST is usable in the presence of errors. Diagnostic information is available in this class.

The parser is invoked by a call to the grammar() method. This method may be invoked only once and on subsequent call throws IllegalStateException

Note that the parser uses a ResourceLocator in order to retrieve the following resources :

1. Grammar source code.
2. Source code of imported grammars.
3. Token vocabulary files.

The default locator is a FileSystemLocator.

After parsing a grammar the parser provides the following diagnostic information:

• errors - a general error flag. More detailed information about errors is provided by getErrors() as a map from error types to boolean values.
• warnings - a general warnings flag. More detailed information about warnings is provided by getWarnings() as a map from error types to boolean values.
• UnknownTerminalNames - the set of unknown terminals in the grammar (if any)
• DuplicateTerminalNames - the set of duplicate terminals in the grammar (if any)
• UnknownNonterminalNames - the set of unknown nonterminals in the grammar (if any)
• DuplicateNonterminalNames - the set of duplicate terminals in the grammar (if any)

In the NioGram mode of the parser all encountered problems are considered errors. In the ANTLR mode the following problems are considered warnings rather than errors:

• NonterminalLiterals
• DotExpressions
• NotSets
• LazyEBNF

Author:

Nikolay Ognyanov

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	Antlr4ToAstParser.GrammarType
static class	Antlr4ToAstParser.Mode Parser mode.

Nested classes/interfaces inherited from interface net.ognyanov.niogram.parser.ErrorDispatcher

ErrorDispatcher.ErrorType

Constructor Summary

Constructors

Constructor and Description
Antlr4ToAstParser(InputStream inputStream) Creates a new parser.
Antlr4ToAstParser(InputStream inputStream, ResourceLocator resourceLocator) Creates a new parser.
Antlr4ToAstParser(String fileName) Creates a new parser.
Antlr4ToAstParser(String fileName, ResourceLocator resourceLocator) Creates a new parser.

Method Summary

Modifier and Type	Method and Description
void	addErrorListener(ErrorListener errorListener) Adds a new error listener to the dispatcher.
List<String>	getDelegateGrammars() Retrieves the list of delegate grammars declared in the parsed grammar.
Set<String>	getDuplicateNonterminalNames() Retrieves the (possibly empty) set of duplicate nonterminals in the parsed grammar.
Set<String>	getDuplicateTerminalNames() Retrieves the (possibly empty) set of duplicate terminals in the parsed grammar.
Set<ErrorListener>	getErrorListeners() Retrieves the set of all error listeners
Map<ErrorDispatcher.ErrorType,Boolean>	getErrors()
String	getFileName() Retrieves the file name of the grammar.
String	getGrammarName() Retrieves the name of the parsed grammar.
Antlr4ToAstParser.GrammarType	getGrammarType() Retrieves the type of the parsed grammar.
Antlr4ToAstParser.Mode	getMode() Retrieves the mode of the parser.
int	getOptionK() Retrieves the value of the option k as specified in the grammar text or -1 if no option k was specified.
List<Pair<String,String>>	getOptions() Retrieves the list of options declared in the grammar
ResourceLocator	getResourceLocator() Retrieves the resource locator used by the parser.
Set<String>	getUnknownNonterminalNames() Retrieves the (possibly empty) set of unknown nonterminals in the parsed grammar.
Set<String>	getUnknownTerminalNames() Retrieves the (possibly empty) set of unknown terminals in the parsed grammar.
Map<ErrorDispatcher.ErrorType,Boolean>	getWarnings()
Grammar	grammar() Invokes the parser.
boolean	hasErrors()
boolean	hasWarnings()
void	notifyErrorListeners(ErrorDispatcher.ErrorType errorType, int line, int position, String message) Notifies all error listeners of the dispatcher of an error.
void	registerError(ErrorDispatcher.ErrorType error) Register that an error has occurred
void	registerWarning(ErrorDispatcher.ErrorType error) Registers that an warning has occurred
void	removeErrorListener(ErrorListener errorListener) Remove an error listener from the dispatcher.
void	removeErrorListeners() Removes all error listeners from the error source;
void	setFileName(String fileName) Sets the file name of the grammar
void	setMode(Antlr4ToAstParser.Mode mode) Sets the mode of the parser.
void	setOptionK(int optionK) Sets the value of the option k to be set as both K and KL into the created grammar.
void	setResourceLocator(ResourceLocator resourceLocator) Sets the resource locator to be used by the parser.
String	toDotString() Generates a DOT language representation of the parse tree.
String	toXmlString() Generates an XML representation of the parse tree.
void	warnErrorListeners(ErrorDispatcher.ErrorType errorType, int line, int position, String message) Notifies all error listeners of the dispatcher of an warning.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

Antlr4ToAstParser

public Antlr4ToAstParser(String fileName,
                         ResourceLocator resourceLocator)
                  throws IOException

Creates a new parser.

Parameters:

fileName - the name of the grammar file

resourceLocator - the resource locator to be used by the parser

Throws:

IOException - if the parser fails to access the grammar file

Antlr4ToAstParser

public Antlr4ToAstParser(String fileName)
                  throws IOException

Creates a new parser. Uses the default FileSystemLocator.

Parameters:

fileName - the name of the grammar file

Throws:

IOException - if the parser fails to access the grammar file

Antlr4ToAstParser

public Antlr4ToAstParser(InputStream inputStream,
                         ResourceLocator resourceLocator)
                  throws IOException

Creates a new parser.

Parameters:

inputStream - an input stream for the grammar text

resourceLocator - the resource locator to be used by the parser

Throws:

IOException - if the parser fails to access the stream

Antlr4ToAstParser

public Antlr4ToAstParser(InputStream inputStream)
                  throws IOException

Creates a new parser. Uses the default FileSystemLocator.

Parameters:

inputStream - an input stream for the grammar text

Throws:

IOException - if the parser fails to access the grammar file

Method Detail

getMode

public Antlr4ToAstParser.Mode getMode()

Retrieves the mode of the parser.

Returns:

the mode

setMode

public void setMode(Antlr4ToAstParser.Mode mode)

Sets the mode of the parser.

Parameters:

mode - the mode to be set

getFileName

public String getFileName()

Retrieves the file name of the grammar.

Specified by:

getFileName in interface ErrorDispatcher

Returns:

the file name or null if it is unknown

setFileName

public void setFileName(String fileName)

Sets the file name of the grammar

Parameters:

fileName - the file name

getResourceLocator

public ResourceLocator getResourceLocator()

Retrieves the resource locator used by the parser.

Returns:

the resource locator

setResourceLocator

public void setResourceLocator(ResourceLocator resourceLocator)

Sets the resource locator to be used by the parser.

Parameters:

resourceLocator - the resource locator

grammar

public Grammar grammar()

Invokes the parser.

Specified by:

grammar in interface AstParser

Returns:

an AST for the grammar or null if the parsing failed because of syntax errors. Note that an AST will be returned in case of semantic errors such as e.g. duplicate or/and missing rules.

getGrammarType

public Antlr4ToAstParser.GrammarType getGrammarType()

Retrieves the type of the parsed grammar.

Returns:

the grammar type

getGrammarName

public String getGrammarName()

Retrieves the name of the parsed grammar.

Returns:

the grammar name

getOptions

public List<Pair<String,String>> getOptions()

Retrieves the list of options declared in the grammar

Returns:

the options

getOptionK

public int getOptionK()

Retrieves the value of the option k as specified in the grammar text or -1 if no option k was specified.

Returns:

the value of the option or -1 if not specified

setOptionK

public void setOptionK(int optionK)

Sets the value of the option k to be set as both K and KL into the created grammar.

Parameters:

optionK - the value of k

getDelegateGrammars

public List<String> getDelegateGrammars()

Retrieves the list of delegate grammars declared in the parsed grammar.

Returns:

the list of delegate grammars

hasErrors

public boolean hasErrors()

getErrors

public Map<ErrorDispatcher.ErrorType,Boolean> getErrors()

hasWarnings

public boolean hasWarnings()

getWarnings

public Map<ErrorDispatcher.ErrorType,Boolean> getWarnings()

getUnknownTerminalNames

public Set<String> getUnknownTerminalNames()

Retrieves the (possibly empty) set of unknown terminals in the parsed grammar.

Returns:

the set of unknown terminals

getDuplicateTerminalNames

public Set<String> getDuplicateTerminalNames()

Retrieves the (possibly empty) set of duplicate terminals in the parsed grammar.

Returns:

the set of duplicated terminals.

getUnknownNonterminalNames

public Set<String> getUnknownNonterminalNames()

Retrieves the (possibly empty) set of unknown nonterminals in the parsed grammar.

Returns:

the set of unknown nonterminals

getDuplicateNonterminalNames

public Set<String> getDuplicateNonterminalNames()

Retrieves the (possibly empty) set of duplicate nonterminals in the parsed grammar.

Returns:

the set of duplicate nonterminals

toXmlString

public String toXmlString()

Generates an XML representation of the parse tree.

Returns:

the XML string

toDotString

public String toDotString()

Generates a DOT language representation of the parse tree. For combined grammars the lexer rules are omitted.

Returns:

the dot string

getErrorListeners

public Set<ErrorListener> getErrorListeners()

Retrieves the set of all error listeners

Specified by:

getErrorListeners in interface ErrorDispatcher

Returns:

the set

addErrorListener

public void addErrorListener(ErrorListener errorListener)

Adds a new error listener to the dispatcher.

Specified by:

addErrorListener in interface ErrorDispatcher

Parameters:

errorListener - the listener.

removeErrorListener

public void removeErrorListener(ErrorListener errorListener)

Remove an error listener from the dispatcher.

Specified by:

removeErrorListener in interface ErrorDispatcher

Parameters:

errorListener - the error listener

removeErrorListeners

public void removeErrorListeners()

Removes all error listeners from the error source;

Specified by:

removeErrorListeners in interface ErrorDispatcher

notifyErrorListeners

public void notifyErrorListeners(ErrorDispatcher.ErrorType errorType,
                                 int line,
                                 int position,
                                 String message)

Notifies all error listeners of the dispatcher of an error.

Specified by:

notifyErrorListeners in interface ErrorDispatcher

Parameters:

errorType - the type of the error

line - the line where a problem was encountered

position - the position in line

message - the error message

warnErrorListeners

public void warnErrorListeners(ErrorDispatcher.ErrorType errorType,
                               int line,
                               int position,
                               String message)

Notifies all error listeners of the dispatcher of an warning.

Specified by:

warnErrorListeners in interface ErrorDispatcher

Parameters:

errorType - the type of the error

line - the line where a problem was encountered

position - the position in line

message - the error message

registerError

public void registerError(ErrorDispatcher.ErrorType error)

Register that an error has occurred

Specified by:

registerError in interface ErrorDispatcher

Parameters:

error - the error type

registerWarning

public void registerWarning(ErrorDispatcher.ErrorType error)

Registers that an warning has occurred

Specified by:

registerWarning in interface ErrorDispatcher

Parameters:

error - the warning type