/// <summary>
/// Tries to create an XPath Function expression if the function Uri correseponds to a supported XPath Function
/// </summary>
/// <param name="u">Function Uri</param>
/// <param name="args">Function Arguments</param>
/// <param name="scalarArgs">Scalar Arguments</param>
/// <param name="expr">Generated Expression</param>
/// <returns>Whether an expression was successfully generated</returns>
public bool TryCreateExpression(Uri u, List<ISparqlExpression> args, Dictionary<String,ISparqlExpression> scalarArgs, out ISparqlExpression expr)
{
//If any Scalar Arguments are present then can't possibly be an XPath Function
if (scalarArgs.Count > 0)
{
expr = null;
return false;
}
String func = u.ToString();
if (func.StartsWith(XPathFunctionFactory.XPathFunctionsNamespace))
{
func = func.Substring(XPathFunctionFactory.XPathFunctionsNamespace.Length);
ISparqlExpression xpathFunc = null;
switch (func)
{
case XPathFunctionFactory.Absolute:
if (args.Count == 1)
{
xpathFunc = new XPathAbsoluteFunction(args.First());
}
else
{
throw new RdfParseException("Incorrect number of arguments for the XPath abs() function");
}
break;
case XPathFunctionFactory.AdjustDateTimeToTimezone:
throw new NotSupportedException("XPath adjust-dateTime-to-timezone() function is not supported");
case XPathFunctionFactory.Boolean:
if (args.Count == 1)
{
xpathFunc = new XPathBooleanFunction(args.First());
}
else
{
throw new RdfParseException("Incorrect number of arguments for the XPath boolean() function");
}
throw new NotSupportedException("XPath boolean() function is not supported");
case XPathFunctionFactory.Ceiling:
if (args.Count == 1)
{
xpathFunc = new XPathCeilingFunction(args.First());
}
else
{
throw new RdfParseException("Incorrect number of arguments for the XPath ceiling() function");
}
break;
case XPathFunctionFactory.Compare:
if (args.Count == 2)
{
xpathFunc = new XPathCompareFunction(args.First(), args.Last());
}
else
{
throw new RdfParseException("Incorrect number of arguments for the XPath compare() function");
}
break;
case XPathFunctionFactory.Concat:
if (args.Count == 2)
{
xpathFunc = new XPathConcatFunction(args.First(), args.Last());
}
else if (args.Count > 2)
{
xpathFunc = new XPathConcatFunction(args);
}
else
{
throw new RdfParseException("Incorrect number of arguments for the XPath concat() function");
}
break;
case XPathFunctionFactory.Contains:
if (args.Count == 2)
{
xpathFunc = new XPathContainsFunction(args.First(), args.Last());
}
else
{
throw new RdfParseException("Incorrect number of arguments for the XPath contains() function");
}
break;
case XPathFunctionFactory.DayFromDateTime:
if (args.Count == 1)
{
xpathFunc = new XPathDayFromDateTimeFunction(args.First());
}
else
{
throw new RdfParseException("Incorrect number of arguments for the XPath day-from-dateTime() function");
}
break;
case XPathFunctionFactory.EncodeForURI:
if (args.Count == 1)
{
xpathFunc = new XPathEncodeForUriFunction(args.First());
}
else
{
throw new RdfParseException("Incorrect number of arguments for the XPath encode-for-uri() function");
}
break;
case XPathFunctionFactory.EndsWith:
if (args.Count == 2)
{
xpathFunc = new XPathEndsWithFunction(args.First(), args.Last());
}
else
{
throw new RdfParseException("Incorrect number of arguments for the XPath ends-with() function");
}
break;
#if !NO_WEB
case XPathFunctionFactory.EscapeHtmlURI:
if (args.Count == 1)
{
xpathFunc = new XPathEscapeHtmlUriFunction(args.First());
}
else
{
throw new RdfParseException("Incorrect number of arguments for the XPath escape-html-uri() function");
}
break;
#endif
case XPathFunctionFactory.False:
if (args.Count == 0)
{
xpathFunc = new BooleanExpressionTerm(false);
}
else
{
throw new RdfParseException("Incorrect number of arguments for the XPath false() function");
}
break;
case XPathFunctionFactory.Floor:
if (args.Count == 1)
{
xpathFunc = new XPathFloorFunction(args.First());
}
else
{
throw new RdfParseException("Incorrect number of arguments for the XPath floor() function");
}
break;
case XPathFunctionFactory.HoursFromDateTime:
if (args.Count == 1)
{
xpathFunc = new XPathHoursFromDateTimeFunction(args.First());
}
else
{
throw new RdfParseException("Incorrect number of arguments for the XPath hours-from-dateTime() function");
}
break;
case XPathFunctionFactory.LowerCase:
if (args.Count == 1)
{
xpathFunc = new XPathLowerCaseFunction(args.First());
}
else
{
throw new RdfParseException("Incorrect number of arguments for the XPath lower-case() function");
}
break;
case XPathFunctionFactory.Matches:
if (args.Count == 2)
{
xpathFunc = new RegexFunction(args.First(), args.Last());
}
else if (args.Count == 3)
{
xpathFunc = new RegexFunction(args.First(), args[1], args.Last());
}
else
{
throw new RdfParseException("Incorrect number of arguments for the XPath matches() function");
}
break;
case XPathFunctionFactory.MinutesFromDateTime:
if (args.Count == 1)
{
xpathFunc = new XPathMinutesFromDateTimeFunction(args.First());
}
else
{
throw new RdfParseException("Incorrect number of arguments for the XPath minutes-from-dateTime() function");
}
break;
case XPathFunctionFactory.MonthFromDateTime:
if (args.Count == 1)
{
xpathFunc = new XPathMonthFromDateTimeFunction(args.First());
}
else
{
throw new RdfParseException("Incorrect number of arguments for the XPath month-from-dateTime() function");
}
break;
case XPathFunctionFactory.NormalizeSpace:
if (args.Count == 1)
{
xpathFunc = new XPathNormalizeSpaceFunction(args.First());
}
else
{
throw new RdfParseException("Incorrect number of arguments for the XPath normalize-space() function");
}
break;
#if !NO_NORM
case XPathFunctionFactory.NormalizeUnicode:
if (args.Count == 1)
{
xpathFunc = new XPathNormalizeUnicodeFunction(args.First());
}
else if (args.Count == 2)
{
xpathFunc = new XPathNormalizeUnicodeFunction(args.First(), args.Last());
}
else
{
throw new RdfParseException("Incorrect number of arguments for the XPath normalize-space() function");
}
break;
#endif
case XPathFunctionFactory.Not:
if (args.Count == 1)
{
xpathFunc = new NegationExpression(args.First());
}
else
{
throw new RdfParseException("Incorrect number of arguments for the XPath not() function");
}
break;
case XPathFunctionFactory.Replace:
if (args.Count == 3)
{
xpathFunc = new XPathReplaceFunction(args.First(), args[1], args.Last());
}
else if (args.Count == 4)
{
xpathFunc = new XPathReplaceFunction(args.First(), args[1], args[2], args.Last());
}
else
{
throw new RdfParseException("Incorrect number of arguments for the XPath replace() function");
}
break;
case XPathFunctionFactory.Round:
if (args.Count == 1)
{
xpathFunc = new XPathRoundFunction(args.First());
}
else
{
throw new RdfParseException("Incorrect number of arguments for the XPath round() function");
}
break;
#if !SILVERLIGHT
case XPathFunctionFactory.RoundHalfToEven:
if (args.Count == 1)
{
xpathFunc = new XPathRoundHalfToEvenFunction(args.First());
}
else if (args.Count == 2)
{
xpathFunc = new XPathRoundHalfToEvenFunction(args.First(), args.Last());
}
else
{
throw new RdfParseException("Incorrect number of arguments for the XPath round-half-to-even() function");
}
break;
#endif
case XPathFunctionFactory.SecondsFromDateTime:
if (args.Count == 1)
{
xpathFunc = new XPathSecondsFromDateTimeFunction(args.First());
}
else
{
throw new RdfParseException("Incorrect number of arguments for the XPath seconds-from-dateTime() function");
}
break;
case XPathFunctionFactory.StartsWith:
if (args.Count == 2)
{
xpathFunc = new XPathStartsWithFunction(args.First(), args.Last());
}
else
{
throw new RdfParseException("Incorrect number of arguments for the XPath starts-with() function");
}
break;
case XPathFunctionFactory.StringJoin:
if (args.Count == 1)
{
xpathFunc = new NonNumericAggregateExpressionTerm(new XPathStringJoinFunction(args.First()));
}
else if (args.Count == 2)
{
xpathFunc = new NonNumericAggregateExpressionTerm(new XPathStringJoinFunction(args.First(), args.Last()));
}
else
{
throw new RdfParseException("Incorrect number of arguments for the XPath string-join() function");
}
break;
case XPathFunctionFactory.StringLength:
if (args.Count == 1)
{
xpathFunc = new XPathStringLengthFunction(args.First());
}
else
{
throw new RdfParseException("Incorrect number of arguments for the XPath string-length() function");
}
break;
case XPathFunctionFactory.Substring:
if (args.Count == 2)
{
xpathFunc = new XPathSubstringFunction(args.First(), args.Last());
}
else if (args.Count == 3)
{
xpathFunc = new XPathSubstringFunction(args.First(), args[1], args.Last());
}
else
{
throw new RdfParseException("Incorrect number of arguments for the XPath substring() function");
}
break;
case XPathFunctionFactory.SubstringAfter:
if (args.Count == 2)
{
xpathFunc = new XPathSubstringAfterFunction(args.First(), args.Last());
}
else
{
throw new RdfParseException("Incorrect number of arguments for the XPath substring-after() function");
}
break;
case XPathFunctionFactory.SubstringBefore:
if (args.Count == 2)
{
xpathFunc = new XPathSubstringBeforeFunction(args.First(), args.Last());
}
else
{
throw new RdfParseException("Incorrect number of arguments for the XPath substring-before() function");
}
break;
case XPathFunctionFactory.TimezoneFromDateTime:
if (args.Count == 1)
{
xpathFunc = new XPathTimezoneFromDateTimeFunction(args.First());
}
else
{
throw new RdfParseException("Incorrect number of arguments for the XPath timezone-from-dateTime() function");
}
break;
case XPathFunctionFactory.Translate:
throw new NotSupportedException("XPath translate() function is not supported");
case XPathFunctionFactory.True:
if (args.Count == 0)
{
xpathFunc = new BooleanExpressionTerm(true);
}
else
{
throw new RdfParseException("Incorrect number of arguments for the XPath true() function");
}
break;
case XPathFunctionFactory.UpperCase:
if (args.Count == 1)
{
xpathFunc = new XPathUpperCaseFunction(args.First());
}
else
{
throw new RdfParseException("Incorrect number of arguments for the XPath upper-case() function");
}
break;
case XPathFunctionFactory.YearFromDateTime:
if (args.Count == 1)
{
xpathFunc = new XPathYearFromDateTimeFunction(args.First());
}
else
{
throw new RdfParseException("Incorrect number of arguments for the XPath year-from-dateTime() function");
}
break;
}
if (xpathFunc != null)
{
expr = xpathFunc;
return true;
}
}
expr = null;
return false;
}
private ISparqlExpression TryParseAggregateExpression(Queue<IToken> tokens)
{
if (this._syntax == SparqlQuerySyntax.Sparql_1_0) throw new RdfParseException("Aggregates are not permitted in SPARQL 1.0");
IToken agg = tokens.Dequeue();
ISparqlExpression aggExpr = null;
bool distinct = false, all = false;
bool scalarArgs = false;
//Expect a Left Bracket next
IToken next = tokens.Dequeue();
if (next.TokenType != Token.LEFTBRACKET)
{
throw Error("Unexpected Token '" + next.GetType().ToString() + "', expected a Left Bracket after an Aggregate Keyword", next);
}
//Then a possible DISTINCT/ALL
next = tokens.Peek();
if (next.TokenType == Token.DISTINCT)
{
distinct = true;
tokens.Dequeue();
}
next = tokens.Peek();
if (next.TokenType == Token.ALL || next.TokenType == Token.MULTIPLY)
{
all = true;
tokens.Dequeue();
}
next = tokens.Peek();
//If we've seen an ALL then we need the closing bracket
if (all && next.TokenType != Token.RIGHTBRACKET)
{
throw Error("Unexpected Token '" + next.GetType().ToString() + "', expected a Right Bracket after the * specifier in an aggregate to terminate the aggregate", next);
}
else if (all && agg.TokenType != Token.COUNT)
{
throw new RdfQueryException("Cannot use the * specifier in aggregates other than COUNT");
}
else if (!all)
{
//If it's not an all then we expect some expression(s)
//Gather the Tokens and parse the Expression
Queue<IToken> subtokens = new Queue<IToken>();
int openBrackets = 1;
List<ISparqlExpression> expressions = new List<ISparqlExpression>();
while (openBrackets > 0)
{
subtokens = new Queue<IToken>();
next = tokens.Dequeue();
do
{
if (next.TokenType == Token.LEFTBRACKET)
{
openBrackets++;
}
else if (next.TokenType == Token.RIGHTBRACKET)
{
openBrackets--;
}
else if (next.TokenType == Token.COMMA)
{
//If we see a comma when we only have 1 bracket open then it is separating argument expressions
if (openBrackets == 1)
{
break;
}
}
else if (next.TokenType == Token.SEMICOLON)
{
//If we see a semicolon when we only have 1 bracket open then this indicates we have scalar arguments in-use
if (openBrackets == 1)
{
scalarArgs = true;
break;
}
}
if (openBrackets > 0)
{
subtokens.Enqueue(next);
next = tokens.Dequeue();
}
} while (openBrackets > 0);
//Parse this expression and add to the list of expressions we're concatenating
expressions.Add(this.Parse(subtokens));
//Once we've hit the ; for the scalar arguments then we can stop looking for expressions
if (scalarArgs) break;
//If we've hit a , then openBrackets will still be one and we'll go around again looking for another expression
//Otherwise we've reached the end of the aggregate and there was no ; for scalar arguments
}
if (expressions.Count == 0) throw new RdfParseException("Aggregate must have at least one argument expression unless they are a COUNT(*)");
if (agg.TokenType == Token.GROUPCONCAT)
{
aggExpr = new XPathConcatFunction(expressions);
}
else
{
if (expressions.Count > 1) throw new RdfParseException("The " + agg.Value + " aggregate does not support more than one argument expression");
aggExpr = expressions.First();
}
}
else
{
tokens.Dequeue();
}
//If the aggregate uses scalar arguments then we'll parse them here
Dictionary<String, ISparqlExpression> scalarArguments = new Dictionary<string, ISparqlExpression>();
if (scalarArgs)
{
scalarArguments = this.TryParseScalarArguments(agg, tokens);
}
//Now we need to generate the actual expression
switch (agg.TokenType)
{
case Token.AVG:
//AVG Aggregate
if (aggExpr is VariableExpressionTerm)
{
return new AggregateExpressionTerm(new AverageAggregate((VariableExpressionTerm)aggExpr, distinct));
}
else
{
return new AggregateExpressionTerm(new AverageAggregate(aggExpr, distinct));
}
case Token.COUNT:
//COUNT Aggregate
if (all)
{
if (distinct)
{
return new AggregateExpressionTerm(new CountAllDistinctAggregate());
}
else
{
return new AggregateExpressionTerm(new CountAllAggregate());
}
}
else if (aggExpr is VariableExpressionTerm)
{
if (distinct)
{
return new AggregateExpressionTerm(new CountDistinctAggregate((VariableExpressionTerm)aggExpr));
}
else
{
return new AggregateExpressionTerm(new CountAggregate((VariableExpressionTerm)aggExpr));
}
}
else
{
if (distinct)
{
return new AggregateExpressionTerm(new CountDistinctAggregate(aggExpr));
}
else
{
return new AggregateExpressionTerm(new CountAggregate(aggExpr));
}
}
case Token.GROUPCONCAT:
if (scalarArgs)
{
if (!scalarArguments.ContainsKey(SparqlSpecsHelper.SparqlKeywordSeparator)) throw new RdfParseException("The GROUP_CONCAT aggregate has Scalar Arguments but does not have the expected SEPARATOR argument");
return new NonNumericAggregateExpressionTerm(new GroupConcatAggregate(aggExpr, scalarArguments[SparqlSpecsHelper.SparqlKeywordSeparator], distinct));
}
else
{
return new NonNumericAggregateExpressionTerm(new GroupConcatAggregate(aggExpr, distinct));
}
case Token.MAX:
//MAX Aggregate
if (aggExpr is VariableExpressionTerm)
{
return new NonNumericAggregateExpressionTerm(new MaxAggregate((VariableExpressionTerm)aggExpr, distinct));
}
else
{
return new NonNumericAggregateExpressionTerm(new MaxAggregate(aggExpr, distinct));
}
case Token.MEDIAN:
//MEDIAN Aggregate
if (this._syntax != SparqlQuerySyntax.Extended) throw new RdfParseException("The MEDIAN aggregate is only supported when the Syntax is set to Extended.");
if (aggExpr is VariableExpressionTerm)
{
return new NonNumericAggregateExpressionTerm(new MedianAggregate((VariableExpressionTerm)aggExpr, distinct));
}
else
{
return new NonNumericAggregateExpressionTerm(new MedianAggregate(aggExpr, distinct));
}
case Token.MIN:
//MIN Aggregate
if (aggExpr is VariableExpressionTerm)
{
return new NonNumericAggregateExpressionTerm(new MinAggregate((VariableExpressionTerm)aggExpr, distinct));
}
else
{
return new NonNumericAggregateExpressionTerm(new MinAggregate(aggExpr, distinct));
}
case Token.MODE:
//MODE Aggregate
if (this._syntax != SparqlQuerySyntax.Extended) throw new RdfParseException("The MODE aggregate is only supported when the Syntax is set to Extended.");
if (aggExpr is VariableExpressionTerm)
{
return new NonNumericAggregateExpressionTerm(new ModeAggregate((VariableExpressionTerm)aggExpr, distinct));
}
else
{
return new NonNumericAggregateExpressionTerm(new ModeAggregate(aggExpr, distinct));
}
case Token.NMAX:
//NMAX Aggregate
if (this._syntax != SparqlQuerySyntax.Extended) throw new RdfParseException("The NMAX (Numeric Maximum) aggregate is only supported when the Syntax is set to Extended. To achieve an equivalent result in SPARQL 1.0/1.1 apply a FILTER to your query so the aggregated variable is only literals of the desired numeric type");
if (aggExpr is VariableExpressionTerm)
{
return new AggregateExpressionTerm(new NumericMaxAggregate((VariableExpressionTerm)aggExpr, distinct));
}
else
{
return new AggregateExpressionTerm(new NumericMaxAggregate(aggExpr, distinct));
}
case Token.NMIN:
//NMIN Aggregate
if (this._syntax != SparqlQuerySyntax.Extended) throw new RdfParseException("The NMIN (Numeric Minimum) aggregate is only supported when the Syntax is set to Extended. To achieve an equivalent result in SPARQL 1.0/1.1 apply a FILTER to your query so the aggregated variable is only literals of the desired numeric type");
if (aggExpr is VariableExpressionTerm)
{
return new AggregateExpressionTerm(new NumericMinAggregate((VariableExpressionTerm)aggExpr, distinct));
}
else
{
return new AggregateExpressionTerm(new NumericMinAggregate(aggExpr, distinct));
}
case Token.SAMPLE:
//SAMPLE Aggregate
if (distinct) throw new RdfParseException("DISTINCT modifier is not valid for the SAMPLE aggregate");
return new NonNumericAggregateExpressionTerm(new SampleAggregate(aggExpr));
case Token.SUM:
//SUM Aggregate
if (aggExpr is VariableExpressionTerm)
{
return new AggregateExpressionTerm(new SumAggregate((VariableExpressionTerm)aggExpr, distinct));
}
else
{
return new AggregateExpressionTerm(new SumAggregate(aggExpr, distinct));
}
default:
//Should have already handled this but have to have it to keep the compiler happy
throw Error("Cannot parse an Aggregate since '" + agg.GetType().ToString() + "' is not an Aggregate Keyword Token", agg);
}
}
