public ParserRunner(Parser <T> parser, ParserContext context)
{
CodeContract.RequiresArgumentNotNull(parser, "parser");
CodeContract.RequiresArgumentNotNull(context, "context");
m_runner = parser.BuildParser(FinalFuture);
Debug.Assert(m_runner != null);
Context = context;
}
public override ParserFunc <TFuture> BuildParser <TFuture>(Future <Lexeme, TFuture> future)
{
ParserFunc <TFuture> scan = null;
scan = (scanner, context) =>
{
var s1 = scanner.Fork();
var l = scanner.Read();
int tokenIndex;
if (LexerStateIndex.HasValue)
{
tokenIndex = l.GetTokenIndex(LexerStateIndex.Value);
}
else
{
tokenIndex = l.TokenIndex;
}
if (tokenIndex == ExpectedToken.Index && m_qualificationPredicate(l))
{
var r = context.StepResult(0, () => future(l)(scanner, context));
return(r);
}
else
{
Lexeme correctionLexeme = l.GetErrorCorrectionLexeme(ExpectedToken.Index, MissingCorrection);
ErrorCorrection insertCorrection = new InsertedErrorCorrection(ExpectedToken.ToString(), correctionLexeme.Value.Span);
if (l.IsEndOfStream)
{
scanner.Join(s1);
return(context.StepResult(1, () => future(correctionLexeme)(scanner, context), insertCorrection)); //insert
}
else
{
ErrorCorrection deleteCorrection = new DeletedErrorCorrection(l);
return(context.ChooseBest(context.StepResult(1, () => future(correctionLexeme)(s1, context), insertCorrection), //insert
context.StepResult(1, () => scan(scanner, context), deleteCorrection))); //delete
}
}
};
return(scan);
}
public override ParserFunc <TFuture> BuildParser <TFuture>(Future <Lexeme, TFuture> future)
{
ParserFunc <TFuture> scan = null;
scan = (scanner, context) =>
{
var l = scanner.Read();
if (l.IsEndOfStream)
{
return(context.StepResult(0, () => future(l)(scanner, context)));
}
ErrorCorrection deleteCorrection = new DeletedErrorCorrection(l);
return(context.StepResult(1, () => scan(scanner, context), deleteCorrection)); //delete to recover
};
return(scan);
}
private ParserFunc(ParserFunc that)
: base(that)
{
_startIdx = that._startIdx;
// 浅拷贝，因为必须在全局保持状态一致
_backtracings = that._backtracings;
// 浅拷贝，因为是不变量
_tokens = that._tokens;
_bnfDefination = that._bnfDefination;
_currentNonTerminal = that._currentNonTerminal;
_currentTokenIdx = that._currentTokenIdx;
_ruleItemIdx = that._ruleItemIdx;
// 浅拷贝，因为回溯会覆盖之前的结果，不会产生影响
_childs = that._childs;
// 浅拷贝，因为是不变量
_ruleList = that._ruleList;
_ruleIdx = that._ruleIdx;
}
public void Assign(Parser <T> assignedParser)
{
CodeContract.RequiresArgumentNotNull(assignedParser, "assignedParser");
Rule = assignedParser.Rule;
}
public void Assign <U>(Parser <U> assignedParser) where U : class, T
{
CodeContract.RequiresArgumentNotNull(assignedParser, "assignedParser");
Rule = assignedParser.Rule;
}
public Parser(ParserFunc <T> rule)
{
Rule = rule;
}
public static Parser <T> Wrap <T>(ParserFunc <T> rule)
{
CodeContract.RequiresArgumentNotNull(rule, "rule");
return(new Parser <T>(rule));
}
