private ISparqlExpression TryParseBuiltInCall(Queue<IToken> tokens)
{
IToken next = tokens.Dequeue();
bool comma = false, first = true;
List<ISparqlExpression> args;
ISparqlExpression strExpr;
switch (next.TokenType)
{
case Token.ABS:
return new AbsFunction(this.TryParseBrackettedExpression(tokens));
case Token.BNODE:
return new BNodeFunction(this.TryParseBrackettedExpression(tokens));
case Token.BOUND:
//Expect a Left Bracket, Variable and then a Right Bracket
next = tokens.Dequeue();
if (next.TokenType == Token.LEFTBRACKET)
{
next = tokens.Dequeue();
if (next.TokenType == Token.VARIABLE)
{
VariableExpressionTerm varExpr = new VariableExpressionTerm(next.Value);
next = tokens.Dequeue();
if (next.TokenType == Token.RIGHTBRACKET)
{
return new BoundFunction(varExpr);
}
else
{
throw Error("Unexpected Token '" + next.GetType().ToString() + "' encountered, a Right Bracket to end a BOUND function call was expected",next);
}
}
else
{
throw Error("Unexpected Token '" + next.GetType().ToString() + "' encountered, a Variable Token for a BOUND function call was expected", next);
}
}
else
{
throw Error("Unexpected Token '" + next.GetType().ToString() + "' encountered, a Left Bracket to start a BOUND function call was expected", next);
}
case Token.CEIL:
return new CeilFunction(this.TryParseBrackettedExpression(tokens));
case Token.COALESCE:
//Get as many argument expressions as we can
args = new List<ISparqlExpression>();
do
{
args.Add(this.TryParseBrackettedExpression(tokens, first, out comma));
first = false;
} while (comma);
return new CoalesceFunction(args);
case Token.CONCAT:
//Get as many argument expressions as we can
args = new List<ISparqlExpression>();
do
{
args.Add(this.TryParseBrackettedExpression(tokens, first, out comma));
first = false;
} while (comma);
return new ConcatFunction(args);
case Token.CONTAINS:
return new ContainsFunction(this.TryParseBrackettedExpression(tokens), this.TryParseBrackettedExpression(tokens, false));
case Token.DATATYPEFUNC:
return new DataTypeFunction(this.TryParseBrackettedExpression(tokens));
case Token.DAY:
return new DayFunction(this.TryParseBrackettedExpression(tokens));
case Token.ENCODEFORURI:
return new EncodeForUriFunction(this.TryParseBrackettedExpression(tokens));
case Token.FLOOR:
return new FloorFunction(this.TryParseBrackettedExpression(tokens));
case Token.HOURS:
return new HoursFunction(this.TryParseBrackettedExpression(tokens));
case Token.IF:
return new IfElseFunction(this.TryParseBrackettedExpression(tokens, true, out comma), this.TryParseBrackettedExpression(tokens, false, out comma), this.TryParseBrackettedExpression(tokens, false, out comma));
case Token.IRI:
case Token.URIFUNC:
return new IriFunction(this.TryParseBrackettedExpression(tokens));
case Token.ISBLANK:
return new IsBlankFunction(this.TryParseBrackettedExpression(tokens));
case Token.ISIRI:
return new IsIriFunction(this.TryParseBrackettedExpression(tokens));
case Token.ISLITERAL:
return new IsLiteralFunction(this.TryParseBrackettedExpression(tokens));
case Token.ISNUMERIC:
return new IsNumericFunction(this.TryParseBrackettedExpression(tokens));
case Token.ISURI:
return new IsUriFunction(this.TryParseBrackettedExpression(tokens));
case Token.LANG:
return new LangFunction(this.TryParseBrackettedExpression(tokens));
case Token.LANGMATCHES:
return new LangMatchesFunction(this.TryParseBrackettedExpression(tokens), this.TryParseBrackettedExpression(tokens, false));
case Token.LCASE:
return new LCaseFunction(this.TryParseBrackettedExpression(tokens));
case Token.MD5:
return new MD5HashFunction(this.TryParseBrackettedExpression(tokens));
case Token.MINUTES:
return new MinutesFunction(this.TryParseBrackettedExpression(tokens));
case Token.MONTH:
return new MonthFunction(this.TryParseBrackettedExpression(tokens));
case Token.NOW:
//Expect a () after the Keyword Token
next = tokens.Dequeue();
if (next.TokenType != Token.LEFTBRACKET) throw Error("Expected a Left Bracket after a NOW keyword to call the NOW() function", next);
next = tokens.Dequeue();
if (next.TokenType != Token.RIGHTBRACKET) throw Error("Expected a Right Bracket after NOW( since the NOW() function does not take any arguments", next);
return new NowFunction();
case Token.RAND:
//Expect a () after the Keyword Token
next = tokens.Dequeue();
if (next.TokenType != Token.LEFTBRACKET) throw Error("Expected a Left Bracket after a RAND keyword to call the RAND() function", next);
next = tokens.Dequeue();
if (next.TokenType != Token.RIGHTBRACKET) throw Error("Expected a Right Bracket after RAND( since the RAND() function does not take any arguments", next);
return new RandFunction();
case Token.REGEX:
return this.TryParseRegexExpression(tokens);
case Token.REPLACE:
//REPLACE may have 3/4 arguments
strExpr = this.TryParseBrackettedExpression(tokens);
ISparqlExpression patternExpr = this.TryParseBrackettedExpression(tokens, false);
ISparqlExpression replaceExpr = this.TryParseBrackettedExpression(tokens, false, out comma);
if (comma)
{
ISparqlExpression opsExpr = this.TryParseBrackettedExpression(tokens, false);
return new ReplaceFunction(strExpr, patternExpr, replaceExpr, opsExpr);
}
else
{
return new ReplaceFunction(strExpr, patternExpr, replaceExpr);
}
case Token.ROUND:
return new RoundFunction(this.TryParseBrackettedExpression(tokens));
case Token.SAMETERM:
return new SameTermFunction(this.TryParseBrackettedExpression(tokens), this.TryParseBrackettedExpression(tokens, false));
case Token.SECONDS:
return new SecondsFunction(this.TryParseBrackettedExpression(tokens));
case Token.SHA1:
return new Sha1HashFunction(this.TryParseBrackettedExpression(tokens));
case Token.SHA224:
return new Sha224HashFunction(this.TryParseBrackettedExpression(tokens));
case Token.SHA256:
return new Sha256HashFunction(this.TryParseBrackettedExpression(tokens));
case Token.SHA384:
return new Sha384HashFunction(this.TryParseBrackettedExpression(tokens));
case Token.SHA512:
return new Sha512HashFunction(this.TryParseBrackettedExpression(tokens));
case Token.STR:
return new StrFunction(this.TryParseBrackettedExpression(tokens));
case Token.STRAFTER:
return new StrAfterFunction(this.TryParseBrackettedExpression(tokens), this.TryParseBrackettedExpression(tokens, false));
case Token.STRBEFORE:
return new StrBeforeFunction(this.TryParseBrackettedExpression(tokens), this.TryParseBrackettedExpression(tokens, false));
case Token.STRDT:
return new StrDtFunction(this.TryParseBrackettedExpression(tokens), this.TryParseBrackettedExpression(tokens, false));
case Token.STRENDS:
return new StrEndsFunction(this.TryParseBrackettedExpression(tokens), this.TryParseBrackettedExpression(tokens, false));
case Token.STRLANG:
return new StrLangFunction(this.TryParseBrackettedExpression(tokens), this.TryParseBrackettedExpression(tokens, false));
case Token.STRLEN:
return new StrLenFunction(this.TryParseBrackettedExpression(tokens));
case Token.STRSTARTS:
return new StrStartsFunction(this.TryParseBrackettedExpression(tokens), this.TryParseBrackettedExpression(tokens, false));
case Token.SUBSTR:
//SUBSTR may have 2/3 arguments
strExpr = this.TryParseBrackettedExpression(tokens);
ISparqlExpression startExpr = this.TryParseBrackettedExpression(tokens, false, out comma);
if (comma)
{
ISparqlExpression lengthExpr = this.TryParseBrackettedExpression(tokens, false);
return new SubStrFunction(strExpr, startExpr, lengthExpr);
}
else
{
return new SubStrFunction(strExpr, startExpr);
}
case Token.TIMEZONE:
return new TimezoneFunction(this.TryParseBrackettedExpression(tokens));
case Token.TZ:
return new TZFunction(this.TryParseBrackettedExpression(tokens));
case Token.UCASE:
return new UCaseFunction(this.TryParseBrackettedExpression(tokens));
case Token.YEAR:
return new YearFunction(this.TryParseBrackettedExpression(tokens));
case Token.EXISTS:
case Token.NOTEXISTS:
if (this._syntax == SparqlQuerySyntax.Sparql_1_0) throw new RdfParseException("EXISTS/NOT EXISTS clauses are not supported in SPARQL 1.0");
if (this._parser == null) throw new RdfParseException("Unable to parse an EXISTS/NOT EXISTS as there is no Query Parser to call into");
//Gather Tokens for the Pattern
NonTokenisedTokenQueue temptokens = new NonTokenisedTokenQueue();
int openbrackets = 0;
bool mustExist = (next.TokenType == Token.EXISTS);
do
{
if (tokens.Count == 0) throw new RdfParseException("Unexpected end of Tokens while trying to parse an EXISTS/NOT EXISTS function");
next = tokens.Dequeue();
if (next.TokenType == Token.LEFTCURLYBRACKET)
{
openbrackets++;
}
else if (next.TokenType == Token.RIGHTCURLYBRACKET)
{
openbrackets--;
}
temptokens.Enqueue(next);
} while (openbrackets > 0);
//Call back into the Query Parser to try and Parse the Graph Pattern for the Function
SparqlQueryParserContext tempcontext = new SparqlQueryParserContext(temptokens);
tempcontext.Query.NamespaceMap.Import(this._nsmapper);
tempcontext.Query.BaseUri = this._baseUri;
return new ExistsFunction(this._parser.TryParseGraphPattern(tempcontext, true), mustExist);
default:
throw Error("Unexpected Token '" + next.GetType().ToString() + "' encountered while trying to parse a Built-in Function call", next);
}
}
private void TryParseSubquery(SparqlQueryParserContext context, GraphPattern p)
{
if (context.SyntaxMode == SparqlQuerySyntax.Sparql_1_0) throw new RdfParseException("Sub-queries are not supported in SPARQL 1.0");
//We're going to make a temporary Token Queue which we will populate and then
//use to create a new SPARQL Query Parser Context
NonTokenisedTokenQueue tokens = new NonTokenisedTokenQueue();
//Assume we've already seen a SELECT
tokens.Enqueue(new BOFToken());
tokens.Enqueue(new SelectKeywordToken(1, 1));
//Now collect Tokens until we hit the closing Right Bracket
int openBrackets = 1;
IToken next;
do
{
next = context.Tokens.Peek();
if (next.TokenType == Token.LEFTCURLYBRACKET)
{
openBrackets++;
}
else if (next.TokenType == Token.RIGHTCURLYBRACKET)
{
openBrackets--;
}
else if (next.TokenType == Token.EOF)
{
throw ParserHelper.Error("Unexpected End of File encountered while trying to gather Tokens to parse a Sub-Query from", next);
}
if (openBrackets > 0)
{
tokens.Enqueue(context.Tokens.Dequeue());
}
} while (openBrackets > 0);
tokens.Enqueue(new EOFToken(0, 0));
//Create a Sub-query Parser Context
SparqlQueryParserContext subcontext = new SparqlQueryParserContext(context, tokens);
subcontext.Query.NamespaceMap.Import(context.Query.NamespaceMap);
SparqlQuery subquery = this.ParseInternal(subcontext);
foreach (SparqlVariable var in subquery.Variables)
{
if (var.IsResultVariable) context.Query.AddVariable("?" + var.Name, false);
}
SubQueryPattern subqueryPattern = new SubQueryPattern(subquery);
p.AddTriplePattern(subqueryPattern);
}