org.stekikun.dolmen.codegen

Class BaseParser.WithPositions<Token>

java.lang.Object

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

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

Enclosing class:

BaseParser<Token>

public abstract static class BaseParser.WithPositions<Token>
extends BaseParser<Token>

Base class for generated parsers which track positions of terminals and non-terminals as the parsing goes on. Positions are then available from semantic actions by using some of the methods inherited from this class:

• getStartPos() / getEndPos()
• getStartPos(int) / getEndPos(int)
• getStartPos(String) / getEndPos(String)

The following methods are also inherited from this class but should only be used by the generated code and not in semantic actions:

• enter(int)
• shift(String)
• leave(String)
• rewind()

Author:

Stéphane Lescuyer

Nested Class Summary

Nested classes/interfaces inherited from class org.stekikun.dolmen.codegen.BaseParser

BaseParser.ParsingException, BaseParser.WithPositions<Token>

Field Summary

Fields inherited from class org.stekikun.dolmen.codegen.BaseParser

_jl_lastTokenEnd, _jl_lastTokenStart, _jl_lexbuf, _jl_nextToken

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	WithPositions(String version, T lexbuf, Function<T,Token> tokens)

Method Summary

Modifier and Type	Method and Description
protected void	enter(int ruleSize) Enters a new rule of the grammar, with room for the locations of ruleSize production items (i.e. terminals or non-terminals)
protected LexBuffer.Position	getEndPos()
protected LexBuffer.Position	getEndPos(int i) Items are numbered from 1, and include all terminals and non-terminals, bound or not.
protected LexBuffer.Position	getEndPos(String id)
protected LexBuffer.Position	getStartPos()
protected LexBuffer.Position	getStartPos(int i) Items are numbered from 1, and include all terminals and non-terminals, bound or not.
protected LexBuffer.Position	getStartPos(String id)
protected LexBuffer.Position	getSymbolStartPos() In comparison to getStartPos(), this is often a better representation of the production's starting position when the first items in a production can match the empty string.
protected void	leave(@Nullable String name) Reduces the current top-level rule, which means that the the stack's current top-level element is popped from the stack and its overall range is appended to the stack's new top-level element.
protected void	rewind() Rewinds the current rule at the top of the location stack, meaning that the positions will be overwritten as new tokens are shifted.
protected void	shift(@Nullable String name) Shifts the last consumed token, which means its position will be registered on the location stack's current top-level element.

Methods inherited from class org.stekikun.dolmen.codegen.BaseParser

eat, parsingError, peek, tokenError

Methods inherited from class java.lang.Object

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

Constructor Detail

WithPositions

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

Method Detail

enter

@DolmenInternal
protected final void enter(int ruleSize)

Enters a new rule of the grammar, with room for the locations of ruleSize production items (i.e. terminals or non-terminals)

Parameters:

ruleSize -

shift

@DolmenInternal
protected final void shift(@Nullable String name)

Shifts the last consumed token, which means its position will be registered on the location stack's current top-level element. The position is bound to name.

Parameters:

name - the name to which this terminal is bound in the rule, or null if it is not bound

leave

@DolmenInternal
protected final void leave(@Nullable String name)

Reduces the current top-level rule, which means that the the stack's current top-level element is popped from the stack and its overall range is appended to the stack's new top-level element. The range is bound to name.

Parameters:

name - the name to which this non-terminal is bound in the rule, or null if it is not bound

rewind

@DolmenInternal
protected final void rewind()

Rewinds the current rule at the top of the location stack, meaning that the positions will be overwritten as new tokens are shifted. This is used to preserve tail-recursion when reentering rules from production items via continuations.

getStartPos

protected final LexBuffer.Position getStartPos()

Returns:

the starting position of the parsed production, or the end position of the last consumed token if the production matched the empty string

getEndPos

protected final LexBuffer.Position getEndPos()

Returns:

the ending position of the parsed production, or the end position of the last consumed token if the production matched the empty string

getSymbolStartPos

protected final LexBuffer.Position getSymbolStartPos()

In comparison to getStartPos(), this is often a better representation of the production's starting position when the first items in a production can match the empty string.

Returns:

the starting position of the first item in the parsed production which matched a non-empty part of the input, or the end position of the last consumed token if the production matched the empty string

getStartPos

protected final LexBuffer.Position getStartPos(int i)

Items are numbered from 1, and include all terminals and non-terminals, bound or not.

Parameters:

i -

Returns:

the starting position of the i-th item in the parsed production

getEndPos

protected final LexBuffer.Position getEndPos(int i)

Items are numbered from 1, and include all terminals and non-terminals, bound or not.

Parameters:

i -

Returns:

the end position of the i-th item in the parsed production

getStartPos

protected final LexBuffer.Position getStartPos(String id)

Parameters:

id -

Returns:

the starting position of the item bound to the name id in the parsed production

getEndPos

protected final LexBuffer.Position getEndPos(String id)

Parameters:

id -

Returns:

the end position of the item bound to the name id in the parsed production