- Added TreeSymbolCloner.java

1 files changed, 103 insertions, 0 deletions

diff --git a/sources/scalac/ast/TreeSymbolCloner.java b/sources/scalac/ast/TreeSymbolCloner.java
new file mode 100644
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+++ b/sources/scalac/ast/TreeSymbolCloner.java
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+/*     ____ ____  ____ ____  ______                                     *\
+**    / __// __ \/ __// __ \/ ____/    SOcos COmpiles Scala             **
+**  __\_ \/ /_/ / /__/ /_/ /\_ \       (c) 2002, LAMP/EPFL              **
+** /_____/\____/\___/\____/____/                                        **
+\*                                                                      */
+
+// $Id$
+
+package scalac.ast;
+
+import java.util.Map;
+import java.util.HashMap;
+
+import scalac.symtab.Symbol;
+import scalac.symtab.SymbolCloner;
+import scalac.util.Name;
+import scalac.util.Debug;
+
+/**
+ * This class implements a tree traverser that clones specified
+ * symbols it encounters.
+ */
+public class TreeSymbolCloner extends Traverser {
+
+    //########################################################################
+    // Private Fields
+
+    // !!! replace Idents in patterns by ValDefs and remove this field
+    /** Indicates whether we are in a pattern */
+    private boolean inPattern = false;
+
+    //########################################################################
+    // Public Fields
+
+    /** The symbol cloner used to clone symbols */
+    public final SymbolCloner cloner;
+
+    //########################################################################
+    // Public Constructors
+
+    /** Initializes a new instance. */
+    public TreeSymbolCloner(SymbolCloner cloner) {
+        this.cloner = cloner;
+    }
+
+    //########################################################################
+    // Public Methods
+
+    /**
+     * Returns true iff the symbol of the given tree symbol must be
+     * cloned. The default implementation returns true iff the tree
+     * defines a symbol and that symbol hasn't been cloned yet.
+     */
+    public boolean mustCloneSymbolOf(Tree tree) {
+        // !!! replace Idents in patterns by ValDefs and remove this switch
+        switch (tree) {
+        case Ident(Name name):
+            if (!inPattern || !name.isVariable()) return false; else break;
+        default:
+            if (!tree.definesSymbol()) return false; else break;
+        }
+        return !cloner.clones.containsKey(tree.symbol());
+    }
+
+    /**
+     * Clones the given symbol. The default implementation invokes
+     * getOwnerOfCloneOf to obtain the owner of the cloned symbol and
+     * then invokes the symbol cloner to clone the symbol.
+     */
+    public Symbol cloneSymbol(Symbol symbol) {
+        return cloner.cloneSymbol(symbol);
+    }
+
+    /**
+     * Traverses the tree and clones symbols. The default
+     * implemenation invokes cloneSymbol with the symbol of every tree
+     * nodes for which mustCloneSymbolOf returns true.
+     */
+    public void traverse(Tree tree) {
+        if (mustCloneSymbolOf(tree)) cloneSymbol(tree.symbol());
+        // !!!replace Idents in patterns by ValDefs and remove this switch
+        switch (tree) {
+        case PatDef(_, Tree pat, Tree rhs):
+            inPattern = true;
+            traverse(pat);
+            inPattern = false;
+            traverse(rhs);
+            return;
+        case CaseDef(Tree pat, Tree guard, Tree body):
+            inPattern = true;
+            traverse(pat);
+            inPattern = false;
+            traverse(guard);
+            traverse(body);
+            return;
+        default:
+            super.traverse(tree);
+            return;
+        }
+    }
+
+    //########################################################################
+}