org.stekikun.dolmen.codegen

Class BaseParser<Token>

java.lang.Object

org.stekikun.dolmen.codegen.BaseParser<Token>

Direct Known Subclasses:

BaseParser.WithPositions

public abstract class BaseParser<Token>
extends Object

Base class for generated parsers.

Generated parsers extend this class to inherit the tokenizer mechanism, as well as the parsing exceptions utilities.

Generated parsers which require systematic position tracking of terminals and non-terminals extend BaseParser.WithPositions, a sub-class of BaseParser.

Author:

Stéphane Lescuyer

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	BaseParser.ParsingException Exception raised by parsing errors in generated parsers
static class	BaseParser.WithPositions<Token> Base class for generated parsers which track positions of terminals and non-terminals as the parsing goes on.

Field Summary

Fields

Modifier and Type	Field and Description
protected LexBuffer.Position	_jl_lastTokenEnd The end position of the last token that was consumed by the parser, or the start-of-input position if no token was consumed yet
protected LexBuffer.Position	_jl_lastTokenStart The start position of the last token that was consumed by the parser, or the start-of-input position if no token was consumed yet
protected LexBuffer	_jl_lexbuf The underlying lexing buffer
protected Token	_jl_nextToken The last token read and not yet consumed, or null if the next token must be fetched from _jl_tokens

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	BaseParser(String version, T lexbuf, Function<T,Token> tokens) Construct a new parser which will feed on the given tokenizer.

Method Summary

Modifier and Type	Method and Description
protected Token	eat() Consumes the next token and returns it
protected BaseParser.ParsingException	parsingError(String msg) Convenience helper which returns a BaseParser.ParsingException located at the last token consumed by the parser.
protected Token	peek()
protected BaseParser.ParsingException	tokenError(Object token, Object... expectedKinds) Convenience function to build a BaseParser.ParsingException when encountering some token which does not correspond to the set of expected token kinds

Methods inherited from class java.lang.Object

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

Field Detail

_jl_lexbuf

@DolmenInternal(read=true)
protected final LexBuffer _jl_lexbuf

The underlying lexing buffer

_jl_nextToken

@DolmenInternal
protected Token _jl_nextToken

The last token read and not yet consumed, or null if the next token must be fetched from _jl_tokens

_jl_lastTokenStart

@DolmenInternal(read=true)
protected LexBuffer.Position _jl_lastTokenStart

The start position of the last token that was consumed by the parser, or the start-of-input position if no token was consumed yet

_jl_lastTokenEnd

@DolmenInternal(read=true)
protected LexBuffer.Position _jl_lastTokenEnd

The end position of the last token that was consumed by the parser, or the start-of-input position if no token was consumed yet

Constructor Detail

BaseParser

protected BaseParser(String version,
                     T lexbuf,
                     Function<T,Token> tokens)

Construct a new parser which will feed on the given tokenizer. The parser is responsible for not calling the supplier unless at least one more token must be consumed:

• the same supplier can be used to parse several top-level entries if applicable;
• it is down to the parser to stop asking for tokens once end-of-input has been reached (which in turn is usually down to the lexer to generate one special token for end-of-input).

Parameters:

version - the version of Dolmen which generated the subclass

lexbuf -

tokens -

Throws:

Exceptions.DolmenVersionException - if version is not equal to the version of this BaseParser

Method Detail

tokenError

protected BaseParser.ParsingException tokenError(Object token,
                                                 Object... expectedKinds)

Convenience function to build a BaseParser.ParsingException when encountering some token which does not correspond to the set of expected token kinds

Parameters:

token -

expectedKinds -

Returns:

an exception with a suitable error message, ready to be thrown

parsingError

protected BaseParser.ParsingException parsingError(String msg)

Convenience helper which returns a BaseParser.ParsingException located at the last token consumed by the parser.

Parameters:

msg -

Returns:

the exception with the given message and the current parsing position

peek

@DolmenInternal
protected final Token peek()

Returns:

the next token to consume, without consuming it

eat

@DolmenInternal
protected final Token eat()

Consumes the next token and returns it