public override string GetErrorMessage(RecognitionException e, string[] tokenNames)
{
string msg = null;
if (e is MismatchedTokenException)
{
MismatchedTokenException mte = (MismatchedTokenException)e;
msg = "mismatched character " + GetCharErrorDisplay(e.Character) + " expecting " + GetCharErrorDisplay(mte.Expecting);
}
else if (e is NoViableAltException)
{
NoViableAltException nvae = (NoViableAltException)e;
// for development, can add "decision=<<"+nvae.grammarDecisionDescription+">>"
// and "(decision="+nvae.decisionNumber+") and
// "state "+nvae.stateNumber
msg = "no viable alternative at character " + GetCharErrorDisplay(e.Character);
}
else if (e is EarlyExitException)
{
EarlyExitException eee = (EarlyExitException)e;
// for development, can add "(decision="+eee.decisionNumber+")"
msg = "required (...)+ loop did not match anything at character " + GetCharErrorDisplay(e.Character);
}
else if (e is MismatchedNotSetException)
{
MismatchedNotSetException mse = (MismatchedNotSetException)e;
msg = "mismatched character " + GetCharErrorDisplay(e.Character) + " expecting set " + mse.Expecting;
}
else if (e is MismatchedSetException)
{
MismatchedSetException mse = (MismatchedSetException)e;
msg = "mismatched character " + GetCharErrorDisplay(e.Character) + " expecting set " + mse.Expecting;
}
else if (e is MismatchedRangeException)
{
MismatchedRangeException mre = (MismatchedRangeException)e;
msg = "mismatched character " + GetCharErrorDisplay(e.Character) + " expecting set " +
GetCharErrorDisplay(mre.A) + ".." + GetCharErrorDisplay(mre.B);
}
else
{
msg = base.GetErrorMessage(e, tokenNames);
}
return(msg);
}
/** <summary>What error message should be generated for the various exception types?</summary>
*
* <remarks>
* Not very object-oriented code, but I like having all error message
* generation within one method rather than spread among all of the
* exception classes. This also makes it much easier for the exception
* handling because the exception classes do not have to have pointers back
* to this object to access utility routines and so on. Also, changing
* the message for an exception type would be difficult because you
* would have to subclassing exception, but then somehow get ANTLR
* to make those kinds of exception objects instead of the default.
* This looks weird, but trust me--it makes the most sense in terms
* of flexibility.
*
* For grammar debugging, you will want to override this to add
* more information such as the stack frame with
* getRuleInvocationStack(e, this.getClass().getName()) and,
* for no viable alts, the decision description and state etc...
*
* Override this to change the message generated for one or more
* exception types.
* </remarks>
*/
public virtual string GetErrorMessage(RecognitionException e, string[] tokenNames)
{
string msg = e.Message;
if (e is UnwantedTokenException)
{
UnwantedTokenException ute = (UnwantedTokenException)e;
string tokenName = "<unknown>";
if (ute.Expecting == TokenTypes.EndOfFile)
{
tokenName = "EndOfFile";
}
else
{
tokenName = tokenNames[ute.Expecting];
}
msg = "extraneous input " + GetTokenErrorDisplay(ute.UnexpectedToken) +
" expecting " + tokenName;
}
else if (e is MissingTokenException)
{
MissingTokenException mte = (MissingTokenException)e;
string tokenName = "<unknown>";
if (mte.Expecting == TokenTypes.EndOfFile)
{
tokenName = "EndOfFile";
}
else
{
tokenName = tokenNames[mte.Expecting];
}
msg = "missing " + tokenName + " at " + GetTokenErrorDisplay(e.Token);
}
else if (e is MismatchedTokenException)
{
MismatchedTokenException mte = (MismatchedTokenException)e;
string tokenName = "<unknown>";
if (mte.Expecting == TokenTypes.EndOfFile)
{
tokenName = "EndOfFile";
}
else
{
tokenName = tokenNames[mte.Expecting];
}
msg = "mismatched input " + GetTokenErrorDisplay(e.Token) +
" expecting " + tokenName;
}
else if (e is MismatchedTreeNodeException)
{
MismatchedTreeNodeException mtne = (MismatchedTreeNodeException)e;
string tokenName = "<unknown>";
if (mtne.Expecting == TokenTypes.EndOfFile)
{
tokenName = "EndOfFile";
}
else
{
tokenName = tokenNames[mtne.Expecting];
}
// workaround for a .NET framework bug (NullReferenceException)
string nodeText = (mtne.Node != null) ? mtne.Node.ToString() ?? string.Empty : string.Empty;
msg = "mismatched tree node: " + nodeText + " expecting " + tokenName;
}
else if (e is NoViableAltException)
{
//NoViableAltException nvae = (NoViableAltException)e;
// for development, can add "decision=<<"+nvae.grammarDecisionDescription+">>"
// and "(decision="+nvae.decisionNumber+") and
// "state "+nvae.stateNumber
msg = "no viable alternative at input " + GetTokenErrorDisplay(e.Token);
}
else if (e is EarlyExitException)
{
//EarlyExitException eee = (EarlyExitException)e;
// for development, can add "(decision="+eee.decisionNumber+")"
msg = "required (...)+ loop did not match anything at input " +
GetTokenErrorDisplay(e.Token);
}
else if (e is MismatchedSetException)
{
MismatchedSetException mse = (MismatchedSetException)e;
msg = "mismatched input " + GetTokenErrorDisplay(e.Token) +
" expecting set " + mse.Expecting;
}
else if (e is MismatchedNotSetException)
{
MismatchedNotSetException mse = (MismatchedNotSetException)e;
msg = "mismatched input " + GetTokenErrorDisplay(e.Token) +
" expecting set " + mse.Expecting;
}
else if (e is FailedPredicateException)
{
FailedPredicateException fpe = (FailedPredicateException)e;
msg = "rule " + fpe.RuleName + " failed predicate: {" +
fpe.PredicateText + "}?";
}
return(msg);
}
