public void CanIncludeBacktrackErrors()
{
var deepBacktrack = FailureMessage.Backtrack(new Position(3, 4),
FailureMessages.Empty
.With(FailureMessage.Expected("A"))
.With(FailureMessage.Expected("B")));
var shallowBacktrack = FailureMessage.Backtrack(new Position(2, 3),
FailureMessages.Empty
.With(FailureMessage.Expected("C"))
.With(FailureMessage.Expected("D"))
.With(deepBacktrack));
var unrelatedBacktrack = FailureMessage.Backtrack(new Position(1, 2),
FailureMessages.Empty
.With(FailureMessage.Expected("E"))
.With(FailureMessage.Expected("F")));
FailureMessages.Empty
.With(deepBacktrack)
.ToString().ShouldBe("[(3, 4): A or B expected]");
FailureMessages.Empty
.With(shallowBacktrack)
.ToString().ShouldBe("[(2, 3): C or D expected [(3, 4): A or B expected]]");
FailureMessages.Empty
.With(FailureMessage.Expected("G"))
.With(FailureMessage.Expected("H"))
.With(shallowBacktrack)
.With(unrelatedBacktrack)
.ToString().ShouldBe("G or H expected [(1, 2): E or F expected] [(2, 3): C or D expected [(3, 4): A or B expected]]");
}
/// <inheritdoc/>
public override IGeneralReply ParseGenerally(TokenStream tokens)
{
var start = tokens.Position;
var reply = _parser.ParseGenerally(tokens);
var newPosition = reply.UnparsedTokens.Position;
if (reply.Success || start == newPosition)
{
return(reply);
}
return(new GeneralFailure(tokens, FailureMessage.Backtrack(newPosition, reply.FailureMessages)));
}
/// <inheritdoc/>
public override IReply <TValue> Parse(TokenStream tokens)
{
var start = tokens.Position;
var reply = _parser.Parse(tokens);
var newPosition = reply.UnparsedTokens.Position;
if (reply.Success || start == newPosition)
{
return(reply);
}
return(new Failure <TValue>(tokens, FailureMessage.Backtrack(newPosition, reply.FailureMessages)));
}
public void CanIndicateErrorsWhichCausedBacktracking()
{
var position = new Position(3, 4);
FailureMessages failures = FailureMessages.Empty
.With(FailureMessage.Expected("a"))
.With(FailureMessage.Expected("b"));
var failure = (BacktrackFailureMessage)FailureMessage.Backtrack(position, failures);
failure.Position.ShouldBe(position);
failure.Failures.ShouldBe(failures);
failure.ToString().ShouldBe("(3, 4): a or b expected");
}
