An base class designed for parsers that use LLLPG (Loyc LL(k) Parser Generator). Note: this is the old (harder to use) base class design. You should use BaseParserForList{Token,MatchType} instead. More...

Source file:

/Core/Loyc.Syntax/Parsing/BaseParser.cs

Inheritance diagram for Loyc.Syntax.BaseParser< Token, MatchType >:

Remarks

An base class designed for parsers that use LLLPG (Loyc LL(k) Parser Generator). Note: this is the old (harder to use) base class design. You should use BaseParserForList{Token,MatchType} instead.

Type Constraints

MatchType

:

IEquatable<MatchType>

Nested classes
struct	SavePosition
	A helper class used by LLLPG for backtracking. More...

Public static fields
static readonly IMessageSink	LogExceptionErrorSink
	Throws LogException when it receives an error. Non-errors are sent to MessageSink.Default. More...

static readonly IMessageSink	FormatExceptionErrorSink

Properties
IMessageSink	ErrorSink `[get, set]`
	Gets or sets the object to which error messages are sent. The default object is LogExceptionErrorSink, which throws an exception if an error occurs. More...

ISourceFile	SourceFile `[get]`
	The ISourceFile object that was provided to the constructor, if any. More...

Token	LT0 `[get]`
	Next token to parse (cached; is set to LT(0) whenever InputPosition is changed). More...

int	InputPosition `[get, set]`
	Current position of the next token to be parsed. More...

abstract MatchType	LA0Int `[get]`
	Returns the token type of _lt0 (normally _lt0.TypeInt) More...

Protected Member Functions
	BaseParser (ISourceFile?file=null, int startIndex=0)
	Initializes the base class. More...

abstract MatchType	EofInt ()
	Returns the value used for EOF (normally 0) More...

abstract Token	LT (int i)
	Returns the token at lookahead i (e.g. `Source[InputPosition + i]` if the tokens come from a list called Source) More...

abstract string	ToString (MatchType tokenType)
	Returns a string representation of the specified token type. These strings are used in error messages. More...

virtual int	LaIndexToCharIndex (int lookaheadIndex)
	Converts a lookahead token index to a character index (used for error reporting). More...

virtual object	LaIndexToMsgContext (int lookaheadIndex)
	Converts a lookahead token index to a SourceRange (or to a string if SourceFile was initialized to null.) More...

virtual void	Error (int lookaheadIndex, string message)
	Records an error or throws an exception. More...

virtual void	Error (int lookaheadIndex, string format, params object?[] args)

void	Skip ()

Token	MatchAny ()

Token	Match (HashSet< MatchType > set, bool inverted=false)

Token	Match (MatchType a)

Token	Match (MatchType a, MatchType b)

Token	Match (MatchType a, MatchType b, MatchType c)

Token	Match (MatchType a, MatchType b, MatchType c, MatchType d)

Token	MatchExcept ()

Token	MatchExcept (MatchType a)

Token	MatchExcept (MatchType a, MatchType b)

Token	MatchExcept (MatchType a, MatchType b, MatchType c)

Token	MatchExcept (MatchType a, MatchType b, MatchType c, MatchType d)

Token	MatchExcept (HashSet< MatchType > set)

bool	TryMatch (HashSet< MatchType > set, bool inverted=false)

bool	TryMatch (MatchType a)

bool	TryMatch (MatchType a, MatchType b)

bool	TryMatch (MatchType a, MatchType b, MatchType c)

bool	TryMatch (MatchType a, MatchType b, MatchType c, MatchType d)

bool	TryMatchExcept ()

bool	TryMatchExcept (MatchType a)

bool	TryMatchExcept (MatchType a, MatchType b)

bool	TryMatchExcept (MatchType a, MatchType b, MatchType c)

bool	TryMatchExcept (MatchType a, MatchType b, MatchType c, MatchType d)

bool	TryMatchExcept (HashSet< MatchType > set)

void	MatchError (bool inverted, params MatchType[] expected)

virtual void	MatchError (bool inverted, IEnumerable< MatchType > expected)
	Handles an error that occurs during Match() or MatchExcept() More...

virtual string	ToString (bool inverted, IEnumerable< MatchType > expected)

virtual void	Check (bool expectation, string expectedDescr="")

Static Protected Member Functions
static HashSet< MatchType >	NewSet (params MatchType[] items)

Protected fields
ISourceFile	_sourceFile

Token	_lt0 = default!

int	_inputPosition

MatchType	EOF

Constructor & Destructor Documentation

Loyc.Syntax.BaseParser< Token, MatchType >.BaseParser	(	ISourceFile?	file = `null`,
		int	startIndex = `0`
	)

inlineprotected

Initializes the base class.

Parameters

file A source file object that will be returned by the SourceFile property. By default, this object is used to get the file name, line number and column number shown in parser errors. If your lexer uses BaseLexer or LexerSource, you can get this object from the BaseLexer{C}.SourceFile property. The SourceFile property (in this class) will return this value. If this parameter is null, then by default, error messages will only show the character index instead of the file, line number and column number.

startIndex The initial value of InputPosition.

Member Function Documentation

abstract MatchType Loyc.Syntax.BaseParser< Token, MatchType >.EofInt ( )

protectedpure virtual

Returns the value used for EOF (normally 0)

Implemented in Loyc.Ecs.Parser.EcsParser, Loyc.Syntax.BaseParserForList< Token, MatchType, List >, and Loyc.Syntax.BaseParserNoBacktracking< Token, Enumerator >.

virtual void Loyc.Syntax.BaseParser< Token, MatchType >.Error	(	int	lookaheadIndex,
		string	message
	)

inlineprotectedvirtual

Records an error or throws an exception.

Parameters

lookaheadIndex Location of the error relative to the current InputPosition. When called by BaseParser, lookaheadIndex is always equal to 0.

The default implementation throws a FormatException. When overriding this method, you can convert the lookaheadIndex to a SourcePos using the expression SourceFile.IndexToLine(LT(lookaheadIndex).StartIndex). This only works if an ISourceFile object was provided to the constructor of this class, and Token implements ISimpleToken.

Reimplemented in Loyc.Ecs.Parser.EcsParser.

virtual int Loyc.Syntax.BaseParser< Token, MatchType >.LaIndexToCharIndex ( int lookaheadIndex )

inlineprotectedvirtual

Converts a lookahead token index to a character index (used for error reporting).

The default implementation does this by trying to cast LT(lookaheadIndex) to ISimpleToken{MatchType}. Returns -1 on failure.

The StartIndex reported by an EOF token is assumed not to be trustworthy (since it is allowed to be a "dummy" token): this method will ensure that the character index returned for EOF is at least as large as SourceFile.Text.Count if a SourceFile was provided, or, otherwise, at least as large as the last token in the file, by scanning backward to find the last token in the file.

virtual object Loyc.Syntax.BaseParser< Token, MatchType >.LaIndexToMsgContext ( int lookaheadIndex )

inlineprotectedvirtual

Converts a lookahead token index to a SourceRange (or to a string if SourceFile was initialized to null.)

The base class can only return a zero-width SourceRange.

abstract Token Loyc.Syntax.BaseParser< Token, MatchType >.LT ( int i )

protectedpure virtual

Returns the token at lookahead i (e.g. Source[InputPosition + i] if the tokens come from a list called Source)

Implemented in Loyc.Ecs.Parser.EcsParser, Loyc.Syntax.BaseParserForList< Token, MatchType, List >, Loyc.Syntax.BaseParserNoBacktracking< Token, Enumerator >, and Loyc.Syntax.ParserSource< Token, MatchType, List >.

virtual void Loyc.Syntax.BaseParser< Token, MatchType >.MatchError	(	bool	inverted,
		IEnumerable< MatchType >	expected
	)

inlineprotectedvirtual

Handles an error that occurs during Match() or MatchExcept()

Parameters

inverted	Set inversion flag. If true, then `expected` is actually a list of things that were NOT expected.
expected	List of items that were expected (or unexpected, if `inverted`)

References Loyc.Localize.Localized().

abstract string Loyc.Syntax.BaseParser< Token, MatchType >.ToString ( MatchType tokenType )

protectedpure virtual

Returns a string representation of the specified token type. These strings are used in error messages.

Implemented in Loyc.Syntax.BaseParserForList< Token, MatchType, List >, and Loyc.Syntax.ParserSource< Token, MatchType, List >.

Member Data Documentation

readonly IMessageSink Loyc.Syntax.BaseParser< Token, MatchType >.FormatExceptionErrorSink

static

Initial value:

= MessageSink.FromDelegate(
            (sev, location, fmt, args) =>
            {
                if (sev >= Severity.Error)
                    throw new FormatException(MessageSink.ContextToString(location) + ": " + Localize.Localized(fmt, args));
                else
                    MessageSink.Default.Write(sev, location, fmt, args);
            })

readonly IMessageSink Loyc.Syntax.BaseParser< Token, MatchType >.LogExceptionErrorSink

static

Initial value:

= MessageSink.FromDelegate(
            (sev, location, fmt, args) =>
            {
                LogMessage msg = new LogMessage(sev, location, fmt, args);
                if (sev >= Severity.Error)
                    throw new LogException(msg);
                else
                    msg.WriteTo(MessageSink.Default);
            })

Throws LogException when it receives an error. Non-errors are sent to MessageSink.Default.

Property Documentation

IMessageSink Loyc.Syntax.BaseParser< Token, MatchType >.ErrorSink

getset

Gets or sets the object to which error messages are sent. The default object is LogExceptionErrorSink, which throws an exception if an error occurs.

int Loyc.Syntax.BaseParser< Token, MatchType >.InputPosition

getsetprotected

Current position of the next token to be parsed.

abstract MatchType Loyc.Syntax.BaseParser< Token, MatchType >.LA0Int

getprotected

Returns the token type of _lt0 (normally _lt0.TypeInt)

Token Loyc.Syntax.BaseParser< Token, MatchType >.LT0

get

Next token to parse (cached; is set to LT(0) whenever InputPosition is changed).

ISourceFile Loyc.Syntax.BaseParser< Token, MatchType >.SourceFile

getprotected

The ISourceFile object that was provided to the constructor, if any.

Remarks

Nested classes

Public static fields

Properties

Protected Member Functions

Static Protected Member Functions

Protected fields

Constructor & Destructor Documentation

Member Function Documentation

Member Data Documentation

Property Documentation