public void CanIncludeBacktrackErrors()
{
var deepBacktrack = ErrorMessage.Backtrack(new Position(3, 4),
ErrorMessageList.Empty
.With(ErrorMessage.Expected("A"))
.With(ErrorMessage.Expected("B")));
var shallowBacktrack = ErrorMessage.Backtrack(new Position(2, 3),
ErrorMessageList.Empty
.With(ErrorMessage.Expected("C"))
.With(ErrorMessage.Expected("D"))
.With(deepBacktrack));
var unrelatedBacktrack = ErrorMessage.Backtrack(new Position(1, 2),
ErrorMessageList.Empty
.With(ErrorMessage.Expected("E"))
.With(ErrorMessage.Expected("F")));
ErrorMessageList.Empty
.With(deepBacktrack)
.ToString().ShouldBe("[(3, 4): A or B expected]");
ErrorMessageList.Empty
.With(shallowBacktrack)
.ToString().ShouldBe("[(2, 3): C or D expected [(3, 4): A or B expected]]");
ErrorMessageList.Empty
.With(ErrorMessage.Expected("G"))
.With(ErrorMessage.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]]");
}
public void CanIndicateErrorsWhichCausedBacktracking()
{
var position = new Position(3, 4);
ErrorMessageList errors = ErrorMessageList.Empty
.With(ErrorMessage.Expected("a"))
.With(ErrorMessage.Expected("b"));
var error = (BacktrackErrorMessage)ErrorMessage.Backtrack(position, errors);
error.Position.ShouldBe(position);
error.Errors.ShouldBe(errors);
error.ToString().ShouldBe("(3, 4): a or b expected");
}