use Appendable rather than StringBuffer for toJava()

[sbp.git] / src / edu / berkeley / sbp / Tree.java

diff --git a/src/edu/berkeley/sbp/Tree.java b/src/edu/berkeley/sbp/Tree.java
index 989224c..cce7bfe 100644 (file)
--- a/src/edu/berkeley/sbp/Tree.java
+++ b/src/edu/berkeley/sbp/Tree.java
@@ -1,57 +1,103 @@
+// Copyright 2006-2007 all rights reserved; see LICENSE file for BSD-style license
+
 package edu.berkeley.sbp;
 import edu.berkeley.sbp.*;
-import edu.berkeley.sbp.*;
 import edu.berkeley.sbp.util.*;
 import java.io.*;
 import java.util.*;
 import java.lang.reflect.*;
 
-/** a tree (or node in a tree); see jargon.txt for details */
-public class Tree<T> {
+/** <font color=blue>a tree (or node in a tree); see jargon.txt for details</font> */
+public class Tree<NodeType>
+    extends PrintableTree<Tree<NodeType>>
+    implements Iterable<Tree<NodeType>> {
 
-    final T           head;
-          Tree<T>[]   children;
-    final Token.Location    location;
+    private static final Tree[] emptyTree = new Tree[0];
 
-    public T                 head()     { return head; }
-    public int               numChildren() { return children.length; }
-    public Iterable<Tree<T>> children() { return new ArrayIterator(children); }
+    private final Input.Region     location;
+    private final NodeType         ihead;
+    private final Tree<NodeType>[] children;
 
-    public       Token.Location    getLocation() { return location; }
+    /** the number of children the tree has */
+    public int               size() { return children.length; }
 
-    public Tree(Token.Location loc, T head)                   { this(loc, head, null); }
-    public Tree(Token.Location loc, T head, Tree<T>[] children) {
-        this.location = loc;
-        this.head = head;
-        Tree<T>[] children2 = children==null ? new Tree[0] : new Tree[children.length];
-        if (children != null) System.arraycopy(children, 0, children2, 0, children.length);
-        this.children = children2;
+    /** the element at the head of the tree */
+    public NodeType                 head()        { return ihead; }
+    public NodeType              getHead()        { return ihead; }
+
+    /** the tree's children */
+    public Iterable<Tree<NodeType>> children()    { return this; }
+
+    /** the tree's children */
+    public Iterator<Tree<NodeType>> iterator()    { return new ArrayIterator(children); }
+
+    /** get the <tt>i</t>th child */
+    public Tree<NodeType> child(int i)            { return children[i]; }
+
+    /** get the input region that this tree was parsed from */
+    public Input.Region    getRegion() { return location; }
+
+    public Tree(Input.Region loc, NodeType head) {
+        location = loc;
+        ihead = head;
+        children = emptyTree;
     }
+    public Tree(Input.Region loc, NodeType head, List<Tree<NodeType>> kids){
+        location = loc;
+        ihead = head;
+        if (kids.size() == 0)
+            children = emptyTree;
+        else {
+            children = new Tree[kids.size()];
+            kids.toArray(children);
+        }
+    }
+    public Tree(Input.Region loc, NodeType head, Tree<NodeType>[] kids) {
+        location = loc;
+        ihead = head;
+        children = (kids == null ? emptyTree : kids.clone());
+    }
+
+    // FIXME: fairly inefficient because we keep copying arrays
+    /** package-private constructor, allows setting the "lift" bit */
+    Tree(Input.Region loc, NodeType head, Tree<NodeType>[] children, boolean[] lifts) {
+        this.location = loc;
+        this.ihead = head;
 
-    /** append Java code to <tt>sb</tt> which evaluates to this instance */
-    public void toJava(StringBuffer sb) {
-        sb.append("new Tree(null, ");
-        sb.append(head==null ? "null" : "\"" + StringUtil.toJavaString(head+"") + "\"");
-        sb.append(", new Tree[] { ");
+        int count = 0;
+        for(int i=0; i<children.length; i++)
+            count += lifts[i] ? children[i].size() : 1;
+
+        this.children = new Tree[count];
+        int j = 0;
         for(int i=0; i<children.length; i++) {
-            if (children[i]==null)   sb.append("null");
-            else                   children[i].toJava(sb);
-            if (i<children.length-1) sb.append(",\n        ");
+            if (!lifts[i])
+                this.children[j++] = children[i];
+            else
+                for(int k=0; k<children[i].size(); k++)
+                    this.children[j++] = children[i].child(k);
         }
-        sb.append("})");
     }
 
-    public String toString() {
-        StringBuffer ret = new StringBuffer();
-        for(int i=0; i<children.length; i++) {
-            String q = children[i]==null ? "null" : children[i].toString();
-            if (q.length() > 0) { ret.append(q); ret.append(" "); }
+
+    // PrintableTree /////////////////////////////////////////////////////////////////////////////
+
+    protected String headToString() { return head()==null?null:head().toString(); }
+    protected String headToJava()   {
+      // FIXME
+        if (head()==null) return null;
+        if (head() instanceof ToJava) {
+            StringBuffer sb = new StringBuffer();
+            try {
+                ((ToJava)head()).toJava(sb);
+            } catch (IOException e) { throw new RuntimeException(e); }
+            return sb.toString();
         }
-        String tail = ret.toString().trim();
-        String h = (head!=null && !head.toString().equals("")) ? (tail.length() > 0 ? head+":" : head+"") : "";
-        if (tail.length() > 0) tail = "{" + tail + "}";
-        return h + tail;
+        return (head()==null?"null":("\""+StringUtil.toJavaString(head().toString())+"\""));
     }
+    protected String left()   { return "{"; }
+    protected String right()  { return "}"; }
+    protected boolean ignoreSingleton() { return false; }
 
 
 }