public override void ReportError( RecognitionException e )
{
StringTemplateGroup group = self.Group;
if ( group == StringTemplate.defaultGroup )
{
self.Error( "action parse error; template context is " + self.GetEnclosingInstanceStackString(), e );
}
else
{
self.Error( "action parse error in group " + self.Group.Name + " line " + self.GroupFileLine + "; template context is " + self.GetEnclosingInstanceStackString(), e );
}
}
public override void ReportError( RecognitionException e )
{
/** TODO: not thought about recovery in lexer yet.
*
// if we've already reported an error and have not matched a token
// yet successfully, don't report any errors.
if ( errorRecovery ) {
//System.err.print("[SPURIOUS] ");
return;
}
errorRecovery = true;
*/
DisplayRecognitionError( this.TokenNames, e );
}
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>
* Lexers can normally match any char in it's vocabulary after matching
* a token, so do the easy thing and just kill a character and hope
* it all works out. You can instead use the rule invocation stack
* to do sophisticated error recovery if you are in a fragment rule.
* </summary>
*/
public virtual void Recover( RecognitionException re )
{
//System.out.println("consuming char "+(char)input.LA(1)+" during recovery");
//re.printStackTrace();
input.Consume();
}
protected virtual void DebugRecognitionException(RecognitionException ex)
{
IDebugEventListener dbg = recognizer.DebugListener;
if (dbg != null)
dbg.RecognitionException(ex);
}
protected override object GetMissingSymbol( IIntStream input,
RecognitionException e,
int expectedTokenType,
BitSet follow)
{
string tokenText = null;
if ( expectedTokenType == TokenTypes.EndOfFile )
tokenText = "<missing EOF>";
else
tokenText = "<missing " + TokenNames[expectedTokenType] + ">";
CommonToken t = new CommonToken( expectedTokenType, tokenText );
IToken current = ( (ITokenStream)input ).LT( 1 );
if ( current.Type == TokenTypes.EndOfFile )
{
current = ( (ITokenStream)input ).LT( -1 );
}
t.Line = current.Line;
t.CharPositionInLine = current.CharPositionInLine;
t.Channel = DefaultTokenChannel;
t.InputStream = current.InputStream;
return t;
}
/** Not currently used */
public virtual object RecoverFromMismatchedSet( IIntStream input,
RecognitionException e,
BitSet follow)
{
if ( MismatchIsMissingToken( input, follow ) )
{
// System.out.println("missing token");
ReportError( e );
// we don't know how to conjure up a token for sets yet
return GetMissingSymbol( input, e, TokenTypes.Invalid, follow );
}
// TODO do single token deletion like above for Token mismatch
throw e;
}
/** <summary>Report a recognition problem.</summary>
*
* <remarks>
* This method sets errorRecovery to indicate the parser is recovering
* not parsing. Once in recovery mode, no errors are generated.
* To get out of recovery mode, the parser must successfully match
* a token (after a resync). So it will go:
*
* 1. error occurs
* 2. enter recovery mode, report error
* 3. consume until token found in resynch set
* 4. try to resume parsing
* 5. next match() will reset errorRecovery mode
*
* If you override, make sure to update syntaxErrors if you care about that.
* </remarks>
*/
public virtual void ReportError( RecognitionException e )
{
// if we've already reported an error and have not matched a token
// yet successfully, don't report any errors.
if ( state.errorRecovery )
{
//System.err.print("[SPURIOUS] ");
return;
}
state.syntaxErrors++; // don't count spurious
state.errorRecovery = true;
DisplayRecognitionError( this.TokenNames, e );
}
/** <summary>
* Recover from an error found on the input stream. This is
* for NoViableAlt and mismatched symbol exceptions. If you enable
* single token insertion and deletion, this will usually not
* handle mismatched symbol exceptions but there could be a mismatched
* token that the match() routine could not recover from.
* </summary>
*/
public virtual void Recover( IIntStream input, RecognitionException re )
{
if ( state.lastErrorIndex == input.Index )
{
// uh oh, another error at same token index; must be a case
// where LT(1) is in the recovery token set so nothing is
// consumed; consume a single token so at least to prevent
// an infinite loop; this is a failsafe.
input.Consume();
}
state.lastErrorIndex = input.Index;
BitSet followSet = ComputeErrorRecoverySet();
BeginResync();
ConsumeUntil( input, followSet );
EndResync();
}
/** <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;
}
/** <summary>What is the error header, normally line/character position information?</summary> */
public virtual string GetErrorHeader( RecognitionException e )
{
string prefix = SourceName ?? string.Empty;
if (prefix.Length > 0)
prefix += ' ';
return string.Format("{0}line {1}:{2}", prefix, e.Line, e.CharPositionInLine + 1);
}
public virtual void DisplayRecognitionError( string[] tokenNames,
RecognitionException e)
{
string hdr = GetErrorHeader( e );
string msg = GetErrorMessage( e, tokenNames );
EmitErrorMessage( hdr + " " + msg );
}
/** <summary>Conjure up a missing token during error recovery.</summary>
*
* <remarks>
* The recognizer attempts to recover from single missing
* symbols. But, actions might refer to that missing symbol.
* For example, x=ID {f($x);}. The action clearly assumes
* that there has been an identifier matched previously and that
* $x points at that token. If that token is missing, but
* the next token in the stream is what we want we assume that
* this token is missing and we keep going. Because we
* have to return some token to replace the missing token,
* we have to conjure one up. This method gives the user control
* over the tokens returned for missing tokens. Mostly,
* you will want to create something special for identifier
* tokens. For literals such as '{' and ',', the default
* action in the parser or tree parser works. It simply creates
* a CommonToken of the appropriate type. The text will be the token.
* If you change what tokens must be created by the lexer,
* override this method to create the appropriate tokens.
* </remarks>
*/
protected virtual object GetMissingSymbol( IIntStream input,
RecognitionException e,
int expectedTokenType,
BitSet follow)
{
return null;
}