/// <summary>
/// Converts from a syntax error to a nice exception.
/// </summary>
/// <param name="e">is the syntax error</param>
/// <param name="expression">is the expression text</param>
/// <param name="parser">the parser that parsed the expression</param>
/// <param name="addPleaseCheck">indicates to add "please check" paraphrases</param>
/// <returns>syntax exception</returns>
public static UniformPair<string> Convert(
RecognitionException e,
string expression,
bool addPleaseCheck,
EsperEPL2GrammarParser parser)
{
if (string.IsNullOrWhiteSpace(expression))
{
var errorMessage = "Unexpected " + END_OF_INPUT_TEXT;
return new UniformPair<string>(errorMessage, expression);
}
IToken t;
IToken tBeforeBefore = null;
IToken tBefore = null;
IToken tAfter = null;
var tIndex = e.OffendingToken != null ? e.OffendingToken.TokenIndex : int.MaxValue;
if (tIndex < parser.TokenStream.Size)
{
t = parser.TokenStream.Get(tIndex);
if ((tIndex + 1) < parser.TokenStream.Size)
{
tAfter = parser.TokenStream.Get(tIndex + 1);
}
if (tIndex - 1 >= 0)
{
tBefore = parser.TokenStream.Get(tIndex - 1);
}
if (tIndex - 2 >= 0)
{
tBeforeBefore = parser.TokenStream.Get(tIndex - 2);
}
}
else
{
if (parser.TokenStream.Size >= 1)
{
tBeforeBefore = parser.TokenStream.Get(parser.TokenStream.Size - 1);
}
if (parser.TokenStream.Size >= 2)
{
tBefore = parser.TokenStream.Get(parser.TokenStream.Size - 2);
}
t = parser.TokenStream.Get(parser.TokenStream.Size - 1);
}
IToken tEnd = null;
if (parser.TokenStream.Size > 0)
{
tEnd = parser.TokenStream.Get(parser.TokenStream.Size - 1);
}
var positionInfo = GetPositionInfo(t);
var token = t.Type == EsperEPL2GrammarParser.Eof ? "end-of-input" : "'" + t.Text + "'";
var stack = parser.GetParaphrases();
var check = "";
var isSelect = stack.Count == 1 && (stack.Peek() == "select clause");
if ((stack.Count > 0) && addPleaseCheck)
{
var delimiter = "";
var checkList = new StringBuilder();
checkList.Append(", please check the ");
while (stack.Count != 0)
{
checkList.Append(delimiter);
checkList.Append(stack.Pop());
delimiter = " within the ";
}
check = checkList.ToString();
}
// check if token is a reserved keyword
var keywords = parser.GetKeywords();
var reservedKeyword = false;
if (keywords.Contains(token.ToLowerInvariant()))
{
token += " (a reserved keyword)";
reservedKeyword = true;
}
else if (tAfter != null && keywords.Contains("'" + tAfter.Text.ToLowerInvariant() + "'"))
{
token += " ('" + tAfter.Text + "' is a reserved keyword)";
reservedKeyword = true;
}
else
{
if ((tBefore != null) &&
(tAfter != null) &&
(keywords.Contains("'" + tBefore.Text.ToLowerInvariant() + "'")) &&
(keywords.Contains("'" + tAfter.Text.ToLowerInvariant() + "'")))
{
token += " ('" + tBefore.Text + "' and '" + tAfter.Text + "' are a reserved keyword)";
reservedKeyword = true;
}
else if ((tBefore != null) &&
(keywords.Contains("'" + tBefore.Text.ToLowerInvariant() + "'")))
{
token += " ('" + tBefore.Text + "' is a reserved keyword)";
reservedKeyword = true;
}
else if (tEnd != null && keywords.Contains("'" + tEnd.Text.ToLowerInvariant() + "'"))
{
token += " ('" + tEnd.Text + "' is a reserved keyword)";
reservedKeyword = true;
}
}
// special handling for the select-clause "as" keyword, which is required
if (isSelect && !reservedKeyword)
{
check += GetSelectClauseAsText(tBeforeBefore, t);
}
var message = "Incorrect syntax near " + token + positionInfo + check;
if (e is NoViableAltException || e is LexerNoViableAltException || CheckForInputMismatchWithNoExpected(e))
{
var nvaeToken = e.OffendingToken;
var nvaeTokenType = nvaeToken != null ? nvaeToken.Type : EsperEPL2GrammarLexer.Eof;
if (nvaeTokenType == EsperEPL2GrammarLexer.Eof)
{
if (token.Equals(END_OF_INPUT_TEXT))
{
message = "Unexpected " + END_OF_INPUT_TEXT + positionInfo + check;
}
else
{
if (ParseHelper.HasControlCharacters(expression))
{
message = "Unrecognized control characters found in text" + positionInfo;
}
else
{
message = "Unexpected " + END_OF_INPUT_TEXT + " near " + token + positionInfo + check;
}
}
}
else {
var parserTokenParaphrases = EsperEPL2GrammarParser.GetParserTokenParaphrases();
if (parserTokenParaphrases.Get(nvaeTokenType) != null)
{
message = "Incorrect syntax near " + token + positionInfo + check;
}
else
{
// find next keyword in the next 3 tokens
var currentIndex = tIndex + 1;
while ((currentIndex > 0) &&
(currentIndex < parser.TokenStream.Size - 1) &&
(currentIndex < tIndex + 3))
{
var next = parser.TokenStream.Get(currentIndex);
currentIndex++;
var quotedToken = "'" + next.Text + "'";
if (parser.GetKeywords().Contains(quotedToken))
{
check += " near reserved keyword '" + next.Text + "'";
break;
}
}
message = "Incorrect syntax near " + token + positionInfo + check;
}
}
}
else if (e is InputMismatchException)
{
var mismatched = (InputMismatchException) e;
string expected;
var expectedTokens = mismatched.GetExpectedTokens().ToList();
if (expectedTokens.Count > 1)
{
var writer = new StringWriter();
writer.Write("any of the following tokens {");
var delimiter = "";
for (var i = 0; i < expectedTokens.Count; i++)
{
writer.Write(delimiter);
if (i > 5)
{
writer.Write("...");
writer.Write(expectedTokens.Count - 5);
writer.Write(" more");
break;
}
delimiter = ", ";
writer.Write(GetTokenText(parser, expectedTokens[i]));
}
writer.Write("}");
expected = writer.ToString();
}
else
{
expected = GetTokenText(parser, expectedTokens[0]);
}
var offendingTokenType = mismatched.OffendingToken.Type;
var unexpected = GetTokenText(parser, offendingTokenType);
var expecting = " expecting " + expected.Trim() + " but found " + unexpected.Trim();
message = "Incorrect syntax near " + token + expecting + positionInfo + check;
}
return new UniformPair<string>(message, expression);
}
/// <summary>
/// Parse expression using the rule the ParseRuleSelector instance supplies.
/// </summary>
/// <param name="expression">text to parse</param>
/// <param name="parseRuleSelector">parse rule to select</param>
/// <param name="addPleaseCheck">true to include depth paraphrase</param>
/// <param name="eplStatementErrorMsg">text for error</param>
/// <param name="rewriteScript">whether to rewrite script expressions</param>
/// <returns>AST - syntax tree</returns>
/// <throws>EPException when the AST could not be parsed</throws>
/// <throws>StatementSpecCompileSyntaxException syntax exceptions</throws>
public static ParseResult Parse(
string expression,
string eplStatementErrorMsg,
bool addPleaseCheck,
ParseRuleSelector parseRuleSelector,
bool rewriteScript)
{
if (Log.IsDebugEnabled)
{
Log.Debug(".parse Parsing expr=" + expression);
}
var input = new CaseInsensitiveInputStream(expression);
var lex = NewLexer(input);
var tokens = new CommonTokenStream(lex);
var parser = ParseHelper.NewParser(tokens);
ITree tree;
try
{
tree = parseRuleSelector.InvokeParseRule(parser);
}
catch (RecognitionException ex)
{
tokens.Fill();
if (rewriteScript)
{
if (IsContainsScriptOrClassExpression(tokens))
{
return HandleScriptAndClassRewrite(tokens, eplStatementErrorMsg, addPleaseCheck, parseRuleSelector);
}
}
Log.Debug("Error parsing statement [" + expression + "]", ex);
throw ExceptionConvertor.ConvertStatement(ex, eplStatementErrorMsg, addPleaseCheck, parser);
}
catch (Exception e)
{
try
{
tokens.Fill();
}
catch (Exception)
{
Log.Debug("Token-fill produced exception: " + e.Message, e);
}
if (Log.IsDebugEnabled)
{
Log.Debug("Error parsing statement [" + eplStatementErrorMsg + "]", e);
}
if (e.InnerException is RecognitionException recognitionException)
{
if (rewriteScript)
{
if (IsContainsScriptOrClassExpression(tokens))
{
return HandleScriptAndClassRewrite(tokens, eplStatementErrorMsg, addPleaseCheck, parseRuleSelector);
}
}
throw ExceptionConvertor.ConvertStatement(recognitionException, eplStatementErrorMsg, addPleaseCheck, parser);
}
throw;
}
// if we are re-writing scripts and contain a script, then rewrite
if (rewriteScript && IsContainsScriptOrClassExpression(tokens))
{
return HandleScriptAndClassRewrite(tokens, eplStatementErrorMsg, addPleaseCheck, parseRuleSelector);
}
if (Log.IsDebugEnabled)
{
Log.Debug(".parse Dumping AST...");
ASTUtil.DumpAST(tree);
}
var expressionWithoutAnnotation = expression;
if (tree is EsperEPL2GrammarParser.StartEPLExpressionRuleContext)
{
var epl = (EsperEPL2GrammarParser.StartEPLExpressionRuleContext) tree;
expressionWithoutAnnotation = GetNoAnnotation(expression, epl.annotationEnum(), tokens);
}
return new ParseResult(
tree,
expressionWithoutAnnotation,
tokens,
EmptyList<string>.Instance,
EmptyList<string>.Instance);
}
