[feature] Complete intermediate AST support for CountExpression

Author: gabriele-tomassetti

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

@@ -1773,21 +1773,24 @@ throws PermissionDeniedException, EXistException, XPathException
                 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/CountClause.java

@@ -0,0 +1,69 @@
+/*
+ * eXist-db Open Source Native XML Database
+ * Copyright (C) 2001 The eXist-db Authors
+ *
+ * [email protected]
+ * http://www.exist-db.org
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
+ */
+package org.exist.xquery;
+
+import org.exist.xquery.util.ExpressionDumper;
+import org.exist.xquery.value.Item;
+import org.exist.xquery.value.Sequence;
+
+/**
+ * Implements a count clause inside a FLWOR expressions.
+ *
+ * @author <a href="mailto:[email protected]">Adam Retter</a>
+ * @author <a href="mailto:[email protected]">Gabriele Tomassetti</a>
+ */
+public class CountClause extends AbstractFLWORClause {
+
+    final String varName;
+
+    public CountClause(final XQueryContext context, final String countName) {
+        super(context);
+        this.varName = countName;
+    }
+
+    @Override
+    public ClauseType getType() {
+        return ClauseType.COUNT;
+    }
+
+    public String getVarName() {
+        return varName;
+    }
+
+    @Override
+    public void analyze(final AnalyzeContextInfo contextInfo) throws XPathException {
+
+    }
+
+    @Override
+    public Sequence eval(final Sequence contextSequence, final Item contextItem) throws XPathException {
+        return null;
+    }
+
+    @Override
+    public void dump(final ExpressionDumper dumper) {
+        dumper.display("count", this.getLine());
+        dumper.startIndent();
+        dumper.display(this.varName);
+        dumper.endIndent().nl();
+    }
+}

exist-core/src/test/java/org/exist/xquery/CountExpressionTest.java

@@ -32,6 +32,7 @@
 import java.io.StringReader;
 
 import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertTrue;
 import static org.junit.jupiter.api.Assertions.fail;
 
 /**
@@ -76,5 +77,8 @@ public void countTest() throws RecognitionException, XPathException, TokenStream
         assertEquals(XQueryParser.LITERAL_count, ast.getNextSibling().getFirstChild().getNextSibling().getNextSibling().getType());
         // rank variable binding
         assertEquals(XQueryParser.VARIABLE_BINDING, ast.getNextSibling().getFirstChild().getNextSibling().getNextSibling().getFirstChild().getType());
+        assertTrue(((ForExpr)expr.getFirst()).returnExpr instanceof OrderByClause);
+        assertTrue(((OrderByClause)(((ForExpr)expr.getFirst()).returnExpr)).returnExpr instanceof CountClause);
+        assertEquals("rank", ((CountClause)((OrderByClause)(((ForExpr)expr.getFirst()).returnExpr)).returnExpr).varName);
     }
 }