- Added TreeCloner.java

1 files changed, 78 insertions, 0 deletions

diff --git a/sources/scalac/ast/TreeCloner.java b/sources/scalac/ast/TreeCloner.java
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+++ b/sources/scalac/ast/TreeCloner.java
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+/*     ____ ____  ____ ____  ______                                     *\
+**    / __// __ \/ __// __ \/ ____/    SOcos COmpiles Scala             **
+**  __\_ \/ /_/ / /__/ /_/ /\_ \       (c) 2002, LAMP/EPFL              **
+** /_____/\____/\___/\____/____/                                        **
+\*                                                                      */
+
+// $Id$
+
+package scalac.ast;
+
+import java.util.Map;
+
+import scalac.Global;
+import scalac.symtab.Symbol;
+import scalac.symtab.Type;
+import scalac.util.Debug;
+
+/**
+ * This class implements a deep tree cloner. It provides support to
+ * change tree symbols and tree types on the fly.
+ */
+public class TreeCloner extends Transformer {
+
+    //########################################################################
+    // Private Fields
+
+    /** The symbol substitution to apply to tree symbols */
+    private final Map/*<Symbol,Symbol>*/ symbols;
+
+    /** The type map to apply to tree types */
+    private final Type.Map types;
+
+    //########################################################################
+    // Public Constructors
+
+    /** Initializes a new instance. */
+    public TreeCloner(Global global, Map symbols, Type.Map types) {
+        super(global, global.make, new StrictTreeCopier(global.make));
+        this.symbols = symbols;
+        this.types = types;
+    }
+
+    //########################################################################
+    // Public Methods
+
+    /**
+     * Returns the symbol for the given cloned tree. The default
+     * implementation returns the result of the application of the
+     * symbol substitution to the given tree's symbol. If there is no
+     * mapping for that symbol returns that same symbol.
+     */
+    public Symbol getSymbolFor(Tree tree) {
+        Symbol oldsym = tree.symbol();
+        Symbol newsym = (Symbol)symbols.get(oldsym);
+        // cloned definitions must have a cloned symbol
+        assert newsym != null || !tree.definesSymbol() : Debug.show(oldsym);
+        return newsym != null ? newsym : oldsym;
+    }
+
+    /**
+     * Returns the type for the given cloned tree. The default
+     * implementation returns the result of the application of the
+     * type map to the given tree's type.
+     */
+    public Type getTypeFor(Tree tree) {
+        return types.apply(tree.type());
+    }
+
+    /** Traverses the given tree and returns a deeply cloned one. */
+    public Tree transform(Tree tree) {
+        tree = super.transform(tree);
+        if (tree.hasSymbol()) tree.setSymbol(getSymbolFor(tree));
+        tree.setType(getTypeFor(tree));
+        return tree;
+    }
+
+    //########################################################################
+}