Transform antlr visitor to be compatible with #2589

antlr4-wrapper.xml

@@ -15,29 +15,103 @@
 
     <property name="target-package-dir" value="${antlr4.outputDirectory}/net/sourceforge/pmd/lang/${lang-terse-name}/ast"/>
 
+
+    <property name="lang-ast-package" value="net.sourceforge.pmd.lang.${lang-terse-name}.ast" />
+    <property name="ast-api-package" value="net.sourceforge.pmd.lang.ast" />
+    <property name="ast-impl-package" value="${ast-api-package}.impl.antlr4" />
+
+
+    <property name="parser-name" value="${lang-name}Parser"/>
+    <property name="parser-file" value="${target-package-dir}/${parser-name}.java"/>
+
+    <property name="visitor-name" value="${lang-name}Visitor"/>
+    <property name="visitor-file" value="${target-package-dir}/${visitor-name}.java"/>
+
+    <property name="base-visitor-name" value="${lang-name}BaseVisitor"/>
+    <property name="base-visitor-file" value="${target-package-dir}/${base-visitor-name}.java"/>
+
+    <property name="node-itf-name" value="${lang-name}Node"/>
+    <property name="base-class-name" value="Abstract${lang-name}Node"/>
+
     <target name="adapt-antlr-sources" description="Adapt antlr sources to the PMD codebase">
 
-        <replace file="${target-package-dir}/${lang-name}Parser.java"
+        <!-- Adapt parser. -->
-                 token="${root-node-name}Context extends ${lang-name}InnerNode"
+        <replace file="${parser-file}">
+            <replacefilter token="${root-node-name}Context extends ${lang-name}InnerNode"
                            value="${root-node-name}Context extends ${lang-name}InnerNode implements net.sourceforge.pmd.lang.ast.RootNode"/>
 
-        <replace file="${target-package-dir}/${lang-name}Parser.java"
+            <replacefilter token="_ctx = _localctx;"
-                 token="_ctx = _localctx;"
                            value="_ctx = _localctx.asAntlrNode();"/>
 
-        <replace file="${target-package-dir}/${lang-name}Parser.java"
+            <replacefilter token="public &lt;T> T accept(ParseTreeVisitor&lt;? extends T> visitor)"
-                 token="else return visitor.visitChildren(this);"
+                           value="public &lt;P, R> R acceptVisitor(AstVisitor&lt;? super P, ? extends R> visitor, P data)" />
-                 value="
-else if (visitor instanceof PmdAntlrVisitor) return ((PmdAntlrVisitor&lt;? extends T>) visitor).visitChildren(this);
-else return visitor.visitChildren(asAntlrNode());"/>
 
-        <replaceregexp flags="g" file="${target-package-dir}/${lang-name}Parser.java">
+            <replacefilter token="((${visitor-name}&lt;? extends T>)visitor)"
+                           value="((${visitor-name}&lt;? super P, ? extends R>) visitor)" />
+
+            <replacefilter token="return visitor.visitChildren(this);"
+                           value="return visitor.visitNode(this, data);" />
+
+        </replace>
+
+        <replaceregexp flags="g" file="${parser-file}">
+            <regexp pattern="\.visit(\w++)\(this\);"/>
+            <substitution expression=".visit\1(this, data);"/>
+        </replaceregexp>
+
+        <replaceregexp flags="g" file="${parser-file}">
             <regexp pattern="_sempred\(\((\w+)\)_localctx,"/>
             <substitution expression="_sempred\((\1) asPmdNode(_localctx),"/>
         </replaceregexp>
 
-        <replace file="${target-package-dir}/${lang-name}Visitor.java"
+        <!-- Transform the visitor to PMD-style. -->
-                 token="extends ParseTreeVisitor"
+        <replace file="${visitor-file}">
-                 value="extends net.sourceforge.pmd.lang.ast.impl.antlr4.PmdAntlrVisitor"/>
+
+            <replacefilter token="Visitor&lt;T> extends ParseTreeVisitor&lt;T> {"
+                           value="Visitor&lt;P, R> extends net.sourceforge.pmd.lang.ast.AstVisitor&lt;P, R> {&#10;
+&#10;
+    /**&#10;
+     * The default visit method for ${lang-name} nodes. Unless overridden,&#10;
+     * the default implementations of the methods of this interface delegate&#10;
+     * to this method. The default calls {@link #visitNode(Node, Object)}.&#10;
+     * &#10;
+     * @param node Node to visit&#10;
+     * @param data Parameter of the visit&#10;
+     * @return Result of the visit&#10;
+     */&#10;
+     default R visit${node-itf-name}(${node-itf-name} node, P data) { return visitNode(node, data); }&#10;&#10;
+&#10;
+"/>
+
+            <replacefilter token="T visit" value="default R visit"/>
+            <replacefilter token="ctx);" value="node, P data) { return visit${node-itf-name}(node, data); }"/>
+
+        </replace>
+
+        <replace file="${visitor-file}">
+
+            <replacefilter token="Visitor&lt;T> extends ParseTreeVisitor&lt;T> {"
+                           value="Visitor&lt;P, R> extends net.sourceforge.pmd.lang.ast.AstVisitor&lt;P, R> {&#10;
+&#10;
+    /**&#10;
+     * The default visit method for ${lang-name} nodes. Unless overridden,&#10;
+     * the default implementations of the methods of this interface delegate&#10;
+     * to this method. The default calls {@link #visitNode(Node, Object)}.&#10;
+     * &#10;
+     * @param node Node to visit&#10;
+     * @param data Parameter of the visit&#10;
+     * @return Result of the visit&#10;
+     */&#10;
+     default R visit${node-itf-name}(${node-itf-name} node, P data) { return visitNode(node, data); }&#10;&#10;
+&#10;
+"/>
+
+            <replacefilter token="T visit" value="default R visit"/>
+            <replacefilter token="ctx);" value="node, P data) { return visit${node-itf-name}(node, data); }"/>
+
+        </replace>
+
+        <!-- This is in the main sources (not much to do). -->
+        <delete file="${base-visitor-file}" />
     </target>
 </project>

pmd-core/src/main/java/net/sourceforge/pmd/lang/ast/AstVisitor.java

@@ -0,0 +1,12 @@
+/*
+ * BSD-style license; for more info see http://pmd.sourceforge.net/license.html
+ */
+
+package net.sourceforge.pmd.lang.ast;
+
+// The AstVisitor of #2589
+public interface AstVisitor<P, R> {
+
+    R visitNode(Node node, P param);
+
+}

pmd-core/src/main/java/net/sourceforge/pmd/lang/ast/AstVisitorBase.java

@@ -0,0 +1,22 @@
+/*
+ * BSD-style license; for more info see http://pmd.sourceforge.net/license.html
+ */
+
+package net.sourceforge.pmd.lang.ast;
+
+// The AstVisitorBase of #2589 (simplified, keep the other instead)
+public abstract class AstVisitorBase<P, R> implements AstVisitor<P, R> {
+
+    protected R visitChildren(Node node, P data) {
+        for (Node child : node.children()) {
+            child.acceptVisitor(this, data);
+        }
+        return null;
+    }
+
+    @Override
+    public R visitNode(Node node, P param) {
+        return visitChildren(node, param);
+    }
+
+}

pmd-core/src/main/java/net/sourceforge/pmd/lang/ast/Node.java

@@ -244,6 +244,7 @@ public interface Node {
         }
     }
 
+
     /**
      * Returns a data map used to store additional information on this node.
      *
@@ -251,6 +252,13 @@ public interface Node {
      */
     DataMap<DataKey<?, ?>> getUserMap();
 
+
+    // The acceptVisitor of #2589
+    default <P, R> R acceptVisitor(AstVisitor<? super P, ? extends R> visitor, P data) {
+        return visitor.visitNode(this, data);
+    }
+
+
     /**
      * Returns the parent of this node, or null if this is the {@linkplain RootNode root}
      * of the tree.
@@ -259,6 +267,7 @@ public interface Node {
      */
     Node getParent();
 
+
     /**
      * Returns the child of this node at the given index.
      *

pmd-core/src/main/java/net/sourceforge/pmd/lang/ast/impl/antlr4/AntlrBaseRule.java

@@ -6,9 +6,8 @@ package net.sourceforge.pmd.lang.ast.impl.antlr4;
 
 import java.util.List;
 
-import org.antlr.v4.runtime.tree.ParseTreeVisitor;
-
 import net.sourceforge.pmd.RuleContext;
+import net.sourceforge.pmd.lang.ast.AstVisitor;
 import net.sourceforge.pmd.lang.ast.Node;
 import net.sourceforge.pmd.lang.rule.AbstractRule;
 
@@ -23,13 +22,11 @@ public abstract class AntlrBaseRule extends AbstractRule {
 
     @Override
     public void apply(List<? extends Node> nodes, RuleContext ctx) {
-        ParseTreeVisitor<Void> visitor = buildVisitor(ctx);
+        AstVisitor<RuleContext, ?> visitor = buildVisitor();
         assert visitor != null : "Rule should provide a non-null visitor";
 
         for (Node node : nodes) {
-            assert node instanceof BaseAntlrNode : "Incorrect node type " + node + " passed to " + this;
+            node.acceptVisitor(visitor, ctx);
-
-            ((BaseAntlrNode<?, ?>) node).accept(visitor);
         }
     }
 
@@ -38,10 +35,8 @@ public abstract class AntlrBaseRule extends AbstractRule {
      * This visitor should explore the nodes it's interested in and report
      * violations on the given rule context.
      *
-     * @param ruleCtx Object that accumulates rule violations
-     *
      * @return A visitor bound to the given rule context
      */
-    public abstract ParseTreeVisitor<Void> buildVisitor(RuleContext ruleCtx);
+    public abstract AstVisitor<RuleContext, ?> buildVisitor();
 
 }

pmd-core/src/main/java/net/sourceforge/pmd/lang/ast/impl/antlr4/AntlrNode.java

@@ -4,8 +4,6 @@
 
 package net.sourceforge.pmd.lang.ast.impl.antlr4;
 
-import org.antlr.v4.runtime.tree.ParseTreeVisitor;
-
 import net.sourceforge.pmd.lang.ast.impl.GenericNode;
 
 /**
@@ -13,6 +11,4 @@ import net.sourceforge.pmd.lang.ast.impl.GenericNode;
  */
 public interface AntlrNode<N extends AntlrNode<N>> extends GenericNode<N> {
 
-    <T> T accept(ParseTreeVisitor<? extends T> visitor);
-
 }

pmd-core/src/main/java/net/sourceforge/pmd/lang/ast/impl/antlr4/BaseAntlrErrorNode.java

@@ -5,7 +5,6 @@
 package net.sourceforge.pmd.lang.ast.impl.antlr4;
 
 import org.antlr.v4.runtime.Token;
-import org.antlr.v4.runtime.tree.ParseTreeVisitor;
 import org.checkerframework.checker.nullness.qual.NonNull;
 
 public abstract class BaseAntlrErrorNode<N extends AntlrNode<N>> extends BaseAntlrTerminalNode<N> {
@@ -20,12 +19,6 @@ public abstract class BaseAntlrErrorNode<N extends AntlrNode<N>> extends BaseAnt
     }
 
 
-    @Override
-    public <T> T accept(ParseTreeVisitor<? extends T> visitor) {
-        return visitor.visitErrorNode(asAntlrNode());
-    }
-
-
     @Override
     public @NonNull String getText() {
         return getFirstAntlrToken().getText();

pmd-core/src/main/java/net/sourceforge/pmd/lang/ast/impl/antlr4/BaseAntlrInnerNode.java

@@ -102,12 +102,6 @@ public abstract class BaseAntlrInnerNode<N extends AntlrNode<N>> extends BaseAnt
         // default does nothing
     }
 
-
-    @Override
-    public <T> T accept(ParseTreeVisitor<? extends T> visitor) {
-        return visitor.visitChildren(asAntlrNode());
-    }
-
     protected static class PmdAsAntlrInnerNode<N extends AntlrNode<N>> extends ParserRuleContext implements RuleNode, AntlrToPmdParseTreeAdapter<N> {
 
         private final BaseAntlrInnerNode<N> pmdNode;
@@ -154,9 +148,7 @@ public abstract class BaseAntlrInnerNode<N extends AntlrNode<N>> extends BaseAnt
 
         @Override
         public <T> T accept(ParseTreeVisitor<? extends T> visitor) {
-            // note: this delegate to the PMD node, giving
+            throw new UnsupportedOperationException("Cannot visit the underlying antlr nodes");
-            // control of the visit back to the first-class nodes
-            return pmdNode.accept(visitor);
         }
     }
 }

pmd-core/src/main/java/net/sourceforge/pmd/lang/ast/impl/antlr4/BaseAntlrTerminalNode.java

@@ -62,11 +62,6 @@ public abstract class BaseAntlrTerminalNode<N extends AntlrNode<N>>
         return 0;
     }
 
-    @Override
-    public <T> T accept(ParseTreeVisitor<? extends T> visitor) {
-        return visitor.visitTerminal(asAntlrNode());
-    }
-
     protected int getTokenKind() {
         return antlrNode.symbol.getTokenIndex();
     }

pmd-core/src/main/java/net/sourceforge/pmd/lang/ast/impl/antlr4/PmdAntlrVisitor.java

@@ -1,27 +0,0 @@
-/*
- * BSD-style license; for more info see http://pmd.sourceforge.net/license.html
- */
-
-package net.sourceforge.pmd.lang.ast.impl.antlr4;
-
-import org.antlr.v4.runtime.tree.ParseTreeVisitor;
-import org.antlr.v4.runtime.tree.RuleNode;
-
-/**
- * Interface for parse tree visitors that can also visit PMD nodes. The
- * antlr rewrite makes the generated visitor interface extend this.
- */
-public interface PmdAntlrVisitor<T> extends ParseTreeVisitor<T> {
-
-    @Override
-    T visitChildren(RuleNode node);
-
-
-    /**
-     * This is added for compatibility.
-     */
-    default T visitChildren(BaseAntlrInnerNode<?> node) {
-        return visitChildren(node.asAntlrNode());
-    }
-
-}

pmd-swift/src/main/antlr4/net/sourceforge/pmd/lang/swift/ast/Swift.g4

@@ -35,6 +35,7 @@ grammar Swift;
 
 @header {
 import net.sourceforge.pmd.lang.ast.impl.antlr4.*;
+import net.sourceforge.pmd.lang.ast.AstVisitor;
 }
 
 

pmd-swift/src/main/java/net/sourceforge/pmd/lang/swift/AbstractSwiftRule.java

@@ -4,9 +4,8 @@
 
 package net.sourceforge.pmd.lang.swift;
 
-import org.antlr.v4.runtime.tree.ParseTreeVisitor;
-
 import net.sourceforge.pmd.RuleContext;
+import net.sourceforge.pmd.lang.ast.AstVisitor;
 import net.sourceforge.pmd.lang.ast.impl.antlr4.AntlrBaseRule;
 
 public abstract class AbstractSwiftRule extends AntlrBaseRule {
@@ -16,5 +15,5 @@ public abstract class AbstractSwiftRule extends AntlrBaseRule {
     }
 
     @Override
-    public abstract ParseTreeVisitor<Void> buildVisitor(RuleContext ruleCtx);
+    public abstract AstVisitor<RuleContext, ?> buildVisitor();
 }

pmd-swift/src/main/java/net/sourceforge/pmd/lang/swift/ast/SwiftInnerNode.java

@@ -6,6 +6,7 @@ package net.sourceforge.pmd.lang.swift.ast;
 
 import org.antlr.v4.runtime.ParserRuleContext;
 
+import net.sourceforge.pmd.lang.ast.AstVisitor;
 import net.sourceforge.pmd.lang.ast.impl.antlr4.BaseAntlrInnerNode;
 
 public abstract class SwiftInnerNode
@@ -19,6 +20,16 @@ public abstract class SwiftInnerNode
         super(parent, invokingStateNumber);
     }
 
+    @Override
+    public <P, R> R acceptVisitor(AstVisitor<? super P, ? extends R> visitor, P data) {
+        if (visitor instanceof SwiftVisitor) {
+            // some of the generated antlr nodes have no accept method...
+            return ((SwiftVisitor<? super P, ? extends R>) visitor).visitSwiftNode(this, data);
+        }
+        return visitor.visitNode(this, data);
+    }
+
+
     @Override // override to make visible in package
     protected PmdAsAntlrInnerNode<SwiftNode> asAntlrNode() {
         return super.asAntlrNode();

pmd-swift/src/main/java/net/sourceforge/pmd/lang/swift/ast/SwiftTerminalNode.java

@@ -5,7 +5,6 @@
 package net.sourceforge.pmd.lang.swift.ast;
 
 import org.antlr.v4.runtime.Token;
-import org.antlr.v4.runtime.tree.ParseTreeVisitor;
 import org.checkerframework.checker.nullness.qual.NonNull;
 
 import net.sourceforge.pmd.lang.ast.impl.antlr4.BaseAntlrTerminalNode;
@@ -28,8 +27,4 @@ public final class SwiftTerminalNode extends BaseAntlrTerminalNode<SwiftNode> im
         return SwiftParser.DICO.getXPathNameOfToken(getFirstAntlrToken().getType());
     }
 
-    @Override
-    public <T> T accept(ParseTreeVisitor<? extends T> visitor) {
-        return visitor.visitTerminal(asAntlrNode());
-    }
 }

pmd-swift/src/main/java/net/sourceforge/pmd/lang/swift/ast/SwiftVisitorBase.java

@@ -0,0 +1,14 @@
+/*
+ * BSD-style license; for more info see http://pmd.sourceforge.net/license.html
+ */
+
+package net.sourceforge.pmd.lang.swift.ast;
+
+import net.sourceforge.pmd.lang.ast.AstVisitorBase;
+
+/**
+ * Base class for swift visitors.
+ */
+public abstract class SwiftVisitorBase<P, R> extends AstVisitorBase<P, R> implements SwiftVisitor<P, R> {
+
+}

pmd-swift/src/main/java/net/sourceforge/pmd/lang/swift/rule/bestpractices/UnavailableFunctionRule.java

@@ -7,11 +7,12 @@ package net.sourceforge.pmd.lang.swift.rule.bestpractices;
 import java.util.List;
 
 import net.sourceforge.pmd.RuleContext;
+import net.sourceforge.pmd.lang.ast.AstVisitor;
 import net.sourceforge.pmd.lang.swift.AbstractSwiftRule;
-import net.sourceforge.pmd.lang.swift.ast.SwiftBaseVisitor;
 import net.sourceforge.pmd.lang.swift.ast.SwiftParser;
 import net.sourceforge.pmd.lang.swift.ast.SwiftParser.FunctionDeclarationContext;
 import net.sourceforge.pmd.lang.swift.ast.SwiftParser.InitializerDeclarationContext;
+import net.sourceforge.pmd.lang.swift.ast.SwiftVisitorBase;
 
 public class UnavailableFunctionRule extends AbstractSwiftRule {
 
@@ -25,11 +26,11 @@ public class UnavailableFunctionRule extends AbstractSwiftRule {
     }
 
     @Override
-    public SwiftBaseVisitor<Void> buildVisitor(RuleContext ruleCtx) {
+    public AstVisitor<RuleContext, ?> buildVisitor() {
-        return new SwiftBaseVisitor<Void>() {
+        return new SwiftVisitorBase<RuleContext, Void>() {
 
             @Override
-            public Void visitFunctionDeclaration(final FunctionDeclarationContext ctx) {
+            public Void visitFunctionDeclaration(final FunctionDeclarationContext ctx, RuleContext ruleCtx) {
                 if (ctx == null) {
                     return null;
                 }
@@ -45,7 +46,7 @@ public class UnavailableFunctionRule extends AbstractSwiftRule {
             }
 
             @Override
-            public Void visitInitializerDeclaration(final InitializerDeclarationContext ctx) {
+            public Void visitInitializerDeclaration(final InitializerDeclarationContext ctx, RuleContext ruleCtx) {
                 if (ctx == null) {
                     return null;
                 }