Support for Count Expressions

exist-core/src/main/antlr/org/exist/xquery/parser/XQuery.g

@@ -103,6 +103,10 @@ options {
 		return buf.toString();
 	}
 
+	public Exception getLastException() {
+		return (Exception) exceptions.get(exceptions.size() - 1);
+	}
+
 	public String getXQDoc() {
 		return lexer.getXQDoc();
 	}
@@ -802,14 +806,21 @@ initialClause throws XPathException
 
 intermediateClause throws XPathException
 :
-    ( initialClause | whereClause | groupByClause | orderByClause )
+    ( initialClause | whereClause | groupByClause | orderByClause | countClause )
     ;
 
 whereClause throws XPathException
 :
 	"where"^ exprSingle
 	;
 
+countClause throws XPathException
+{ String varName; }
+:
+	"count"^ DOLLAR! varName=varName!
+	{ #countClause = #(#countClause, #[VARIABLE_BINDING, varName]); }
+	;
+
 forClause throws XPathException
 :
 	"for"^ inVarBinding ( COMMA! inVarBinding )*
@@ -2223,6 +2234,8 @@ reservedKeywords returns [String name]
 	|
 	"array" { name = "array"; }
 	|
+	"count" { name = "count"; }
+	|
 	"copy-namespaces" { name = "copy-namespaces"; }
 	|
 	"empty-sequence" { name = "empty-sequence"; }

exist-core/src/main/antlr/org/exist/xquery/parser/XQueryTree.g

@@ -128,9 +128,9 @@ options {
 
     private static class ForLetClause {
         XQueryAST ast;
-        String varName;
+        QName varName;
         SequenceType sequenceType= null;
-        String posVar= null;
+        QName posVar = null;
         Expression inputSequence;
         Expression action;
         FLWORClause.ClauseType type = FLWORClause.ClauseType.FOR;
@@ -1398,7 +1398,11 @@ throws PermissionDeniedException, EXistException, XPathException
                 )?
                 step=expr[inputSequence]
                 {
-                    clause.varName= someVarName.getText();
+                    try {
+                        clause.varName = QName.parse(staticContext, someVarName.getText(), null);
+                    } catch (final IllegalQNameException iqe) {
+                        throw new XPathException(someVarName.getLine(), someVarName.getColumn(), ErrorCodes.XPST0081, "No namespace defined for prefix " + someVarName.getText());
+                    }
                     clause.inputSequence= inputSequence;
                     clauses.add(clause);
                 }
@@ -1449,7 +1453,11 @@ throws PermissionDeniedException, EXistException, XPathException
                 )?
                 step=expr[inputSequence]
                 {
-                    clause.varName= everyVarName.getText();
+                    try {
+                        clause.varName = QName.parse(staticContext, everyVarName.getText(), null);
+                    } catch (final IllegalQNameException iqe) {
+                        throw new XPathException(everyVarName.getLine(), everyVarName.getColumn(), ErrorCodes.XPST0081, "No namespace defined for prefix " + everyVarName.getText());
+                    }
                     clause.inputSequence= inputSequence;
                     clauses.add(clause);
                 }
@@ -1585,11 +1593,21 @@ throws PermissionDeniedException, EXistException, XPathException
                         )?
                         (
                             posVar:POSITIONAL_VAR
-                            { clause.posVar= posVar.getText(); }
+                            {
+                                try {
+                                    clause.posVar = QName.parse(staticContext, posVar.getText(), null);
+                                } catch (final IllegalQNameException iqe) {
+                                    throw new XPathException(posVar.getLine(), posVar.getColumn(), ErrorCodes.XPST0081, "No namespace defined for prefix " + posVar.getText());
+                                }
+                            }
                         )?
                         step=expr [inputSequence]
                         {
-                            clause.varName= varName.getText();
+                            try {
+                                clause.varName = QName.parse(staticContext, varName.getText(), null);
+                            } catch (final IllegalQNameException iqe) {
+                                throw new XPathException(varName.getLine(), varName.getColumn(), ErrorCodes.XPST0081, "No namespace defined for prefix " + varName.getText());
+                            }
                             clause.inputSequence= inputSequence;
                             clauses.add(clause);
                         }
@@ -1618,7 +1636,11 @@ throws PermissionDeniedException, EXistException, XPathException
                         )?
                         step=expr [inputSequence]
                         {
-                            clause.varName= letVarName.getText();
+                            try {
+                                clause.varName = QName.parse(staticContext, letVarName.getText(), null);
+                            } catch (final IllegalQNameException iqe) {
+                                throw new XPathException(letVarName.getLine(), letVarName.getColumn(), ErrorCodes.XPST0081, "No namespace defined for prefix " + letVarName.getText());
+                            }
                             clause.inputSequence= inputSequence;
                             clauses.add(clause);
                         }
@@ -1752,29 +1774,49 @@ throws PermissionDeniedException, EXistException, XPathException
                     clauses.add(clause);
                 }
             )
-        )+
-        step=expr [(PathExpr) action]
-        {
+            |
+            #(
+            	co:"count"
+            	countVarName:VARIABLE_BINDING
+                {
+                    ForLetClause clause = new ForLetClause();
+                    clause.ast = co;
+                    try {
+                        clause.varName = QName.parse(staticContext, countVarName.getText(), null);
+                    } catch (final IllegalQNameException iqe) {
+                        throw new XPathException(countVarName.getLine(), countVarName.getColumn(), ErrorCodes.XPST0081, "No namespace defined for prefix " + countVarName.getText());
+                    }
+                    clause.type = FLWORClause.ClauseType.COUNT;
+                    clause.inputSequence = null;
+                    clauses.add(clause);
+                }
+            )
+		)+
+		step=expr [(PathExpr) action]
+		{
             for (int i= clauses.size() - 1; i >= 0; i--) {
                 ForLetClause clause= (ForLetClause) clauses.get(i);
                 FLWORClause expr;
                 switch (clause.type) {
                     case LET:
-                        expr= new LetExpr(context);
+                        expr = new LetExpr(context);
                         expr.setASTNode(expr_AST_in);
                         break;
                     case GROUPBY:
-                expr = new GroupByClause(context);
-                break;
-            case ORDERBY:
-                expr = new OrderByClause(context, clause.orderSpecs);
-                break;
-                        case WHERE:
-                                expr = new WhereClause(context, new DebuggableExpression(clause.inputSequence));
-                                break;
-            default:
-                expr= new ForExpr(context, clause.allowEmpty);
-                break;
+                        expr = new GroupByClause(context);
+                        break;
+                    case ORDERBY:
+                        expr = new OrderByClause(context, clause.orderSpecs);
+                        break;
+                    case WHERE:
+                        expr = new WhereClause(context, new DebuggableExpression(clause.inputSequence));
+                        break;
+                    case COUNT:
+                        expr = new CountClause(context, clause.varName);
+                        break;
+                    default:
+                        expr = new ForExpr(context, clause.allowEmpty);
+                        break;
                 }
                 expr.setASTNode(clause.ast);
                 if (clause.type == FLWORClause.ClauseType.FOR || clause.type == FLWORClause.ClauseType.LET) {

exist-core/src/main/java/org/exist/xquery/AbstractFLWORClause.java

@@ -41,14 +41,10 @@ public AbstractFLWORClause(XQueryContext context) {
     }
 
     @Override
-    public LocalVariable createVariable(final String name) throws XPathException {
-        try {
-            final LocalVariable var = new LocalVariable(QName.parse(context, name, null));
-            firstVar = var;
-            return var;
-        } catch (final IllegalQNameException e) {
-            throw new XPathException(this, ErrorCodes.XPST0081, "No namespace defined for prefix " + name);
-        }
+    public LocalVariable createVariable(final QName name) throws XPathException {
+        final LocalVariable var = new LocalVariable(name);
+        firstVar = var;
+        return var;
     }
 
     @Override

exist-core/src/main/java/org/exist/xquery/BasicExpressionVisitor.java

@@ -180,6 +180,11 @@ public void visitOrderByClause(final OrderByClause orderBy) {
         // Nothing to do
     }
 
+    @Override
+    public void visitCountClause(final CountClause count) {
+        // Nothing to do
+    }
+
     @Override
     public void visitGroupByClause(final GroupByClause groupBy) {
         // Nothing to do

exist-core/src/main/java/org/exist/xquery/BindingExpression.java

@@ -23,13 +23,14 @@
 
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
+import org.exist.dom.QName;
 import org.exist.dom.persistent.*;
 import org.exist.numbering.NodeId;
 import org.exist.storage.UpdateListener;
 import org.exist.xquery.value.*;
 
 /**
- * Abstract superclass for the variable binding expressions "for" and "let".
+ * Abstract superclass for the variable binding expressions "for", "let", and "count".
  * 
  * @author <a href="mailto:wolfgang@exist-db.org">Wolfgang Meier</a>
  */
@@ -41,22 +42,20 @@
     protected final static SequenceType POSITIONAL_VAR_TYPE = 
         new SequenceType(Type.INTEGER, Cardinality.EXACTLY_ONE);
 
-	protected String varName;
+	protected QName varName;
 	protected SequenceType sequenceType = null;
 	protected Expression inputSequence;
-
 	private ExprUpdateListener listener;
 
-
-    public BindingExpression(XQueryContext context) {
+    public BindingExpression(final XQueryContext context) {
 		super(context);
 	}
 
-	public void setVariable(String qname) {
-		varName = qname;
+	public void setVariable(final QName varName) {
+		this.varName = varName;
 	}
 
-    public String getVariable() {
+    public QName getVariable() {
         return this.varName;
     }
 
@@ -77,52 +76,45 @@
         return this.inputSequence;
     }
 
-    /* (non-Javadoc)
-             * @see org.exist.xquery.Expression#analyze(org.exist.xquery.Expression, int)
-             */
-    public void analyze(AnalyzeContextInfo contextInfo) throws XPathException {
+    @Override
+    public void analyze(final AnalyzeContextInfo contextInfo) throws XPathException {
         unordered = (contextInfo.getFlags() & UNORDERED) > 0;
     }
 
     @Override
     public Sequence postEval(Sequence seq) throws XPathException {
-        if (returnExpr instanceof FLWORClause) {
-            seq = ((FLWORClause)returnExpr).postEval(seq);
+        if (returnExpr instanceof FLWORClause flworClause) {
+            seq = flworClause.postEval(seq);
         }
         return super.postEval(seq);
     }
 
-	/* (non-Javadoc)
-	 * @see org.exist.xquery.Expression#preselect(org.exist.dom.persistent.DocumentSet, org.exist.xquery.StaticContext)
-	 */
-	public DocumentSet preselect(DocumentSet in_docs) throws XPathException {
-		return in_docs;
+	public DocumentSet preselect(final DocumentSet docs) throws XPathException {
+		return docs;
 	}
 
-	/* (non-Javadoc)
-	 * @see org.exist.xquery.AbstractExpression#resetState()
-	 */
-	public void resetState(boolean postOptimization) {
+	@Override
+	public void resetState(final boolean postOptimization) {
 		super.resetState(postOptimization);
 		inputSequence.resetState(postOptimization);
 		returnExpr.resetState(postOptimization);
 	}
 
-	public final static void setContext(int contextId, Sequence seq) throws XPathException {
+	public static void setContext(final int contextId, final Sequence seq) throws XPathException {
 		if (seq instanceof VirtualNodeSet) {
 			((VirtualNodeSet)seq).setInPredicate(true);
             ((VirtualNodeSet)seq).setSelfIsContext();
 		} else {
-			Item next;
-			for (final SequenceIterator i = seq.unorderedIterator(); i.hasNext();) {
-				next = i.nextItem(); 
-				if (next instanceof NodeProxy)
-					 {((NodeProxy) next).addContextNode(contextId, (NodeProxy) next);}
+			for (final SequenceIterator i = seq.unorderedIterator(); i.hasNext(); ) {
+				final Item next = i.nextItem();
+				if (next instanceof NodeProxy) {
+					((NodeProxy) next).addContextNode(contextId, (NodeProxy) next);
+				}
 			}
 		}
 	}
 
-	public final static void clearContext(int contextId, Sequence seq) throws XPathException {
+	public final static void clearContext(final int contextId, final Sequence seq) throws XPathException {
 		if (seq != null && !(seq instanceof VirtualNodeSet)) {
             seq.clearContext(contextId);
 		}
@@ -132,27 +124,29 @@
         if (listener == null) {
             listener = new ExprUpdateListener(sequence);
             context.registerUpdateListener(listener);
-        } else
-            {listener.setSequence(sequence);}
+        } else {
+			listener.setSequence(sequence);
+		}
     }
 
     private class ExprUpdateListener implements UpdateListener {
         private Sequence sequence;
 
-        public ExprUpdateListener(Sequence sequence) {
+        public ExprUpdateListener(final Sequence sequence) {
             this.sequence = sequence;
         }
 
-        public void setSequence(Sequence sequence) {
+        public void setSequence(final Sequence sequence) {
             this.sequence = sequence;
         }
 
         @Override
-        public void documentUpdated(DocumentImpl document, int event) {
+        public void documentUpdated(final DocumentImpl document, final int event) {
+			// no-op
         }
 
         @Override
-        public void nodeMoved(NodeId oldNodeId, NodeHandle newNode) {
+        public void nodeMoved(final NodeId oldNodeId, final NodeHandle newNode) {
             sequence.nodeMoved(oldNodeId, newNode);
         }
 
@@ -163,6 +157,7 @@
 
         @Override
         public void debug() {
+			// no-op
         }
     }
 
@@ -178,11 +173,12 @@
 	/* RewritableExpression API */
 
 	@Override
-	public void replace(Expression oldExpr, Expression newExpr) {
-		if (inputSequence == oldExpr)
-			{inputSequence = newExpr;}
-		else if (returnExpr == oldExpr)
-			{returnExpr = newExpr;}
+	public void replace(final Expression oldExpr, final Expression newExpr) {
+		if (inputSequence == oldExpr) {
+			inputSequence = newExpr;
+		} else if (returnExpr == oldExpr) {
+			returnExpr = newExpr;
+		}
 	}
 
 	@Override
@@ -196,7 +192,8 @@
 	}
 
 	@Override
-	public void remove(Expression oldExpr) throws XPathException {
+	public void remove(final Expression oldExpr) throws XPathException {
+		// no-op
 	}
 
 	/* END RewritableExpression API */