Added support for dumping AST to console, text file or dot file

compiler/java/com/google/dart/compiler/ast/viz/DotWriter.java

Index: compiler/java/com/google/dart/compiler/ast/viz/DotWriter.java
===================================================================
--- compiler/java/com/google/dart/compiler/ast/viz/DotWriter.java	(revision 0)
+++ compiler/java/com/google/dart/compiler/ast/viz/DotWriter.java	(revision 0)
@@ -0,0 +1,118 @@
+// Copyright (c) 2011, the Dart project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+
+package com.google.dart.compiler.ast.viz;
+
+import java.io.File;
+import java.io.FileWriter;
+import java.io.IOException;
+import java.util.HashMap;
+import java.util.Map;
+
+import com.google.dart.compiler.ast.DartNode;
+import com.google.dart.compiler.ast.DartUnit;
+
+/**
+ * Write the AST in Dot format. Output file is placed
+ * next to the JS file in the output directory
+ */
+public class DotWriter extends BaseASTWriter{
+
+  Map<DartNode,String> nodeMap;

[zundel, 2011/11/15 14:49:54]

make final

[shauvik, 2011/11/15 23:53:14]

Can't make final. I am reusing this class for all units. This comment helped me
find a bug. Basically nodes need to be reinitialized for every Dart Unit. Added
a fix for that.

On 2011/11/15 14:49:54, zundel wrote:

+  FileWriter out;
+  StringBuffer edges = new StringBuffer();

[zundel, 2011/11/15 14:49:54]

make final

[shauvik, 2011/11/15 23:53:14]

same as above

On 2011/11/15 14:49:54, zundel wrote:

+  StringBuffer nodes = new StringBuffer();

[zundel, 2011/11/15 14:49:54]

make final

[shauvik, 2011/11/15 23:53:14]

same as above

On 2011/11/15 14:49:54, zundel wrote:

+  
+  public DotWriter(String outputDir) {
+    super(outputDir);
+    this.nodeMap = new HashMap<DartNode, String>();
+  }
+  
+  @Override
+  protected void startHook() {
+    String nodeData = String.format("%s", currentUnit.getSourceName());
+    nodeMap.put(this.currentUnit, nodeData);
+  }
+  
+  @Override
+  protected void endHook() {
+    if(edges.length() > 0){
+      String dotGraph = "digraph G{\n" +nodes.toString() 
+          + edges.toString() + "}";
+      try {
+        out.append(dotGraph);
+        out.flush();
+        out.close();
+      } catch (IOException e) {
+        System.err.println("Error while writing AST to dot file");
+        e.printStackTrace();
+      }
+    }
+  }
+  
+  public void write(String nodeType, DartNode node){
+    write(nodeType, node, "");
+  }
+  
+  public void write(String nodeType, DartNode node, String data) {
+    String nodeData = node.getSourceLine() + ":"+node.getSourceStart() 
+        + ":" +node.getSourceLength() + "_" + nodeType;
+    this.nodeMap.put(node, nodeData);
+    DartNode parent = node.getParent();
+    if(parent == null){
+      parent = this.currentUnit;
+    }
+    String styleAttr = getStyleAttr(nodeType, node);
+    String label = getLabel(nodeType,data);
+    nodes.append(String.format("\"%s\" [label=\"%s\"%s];\n", 
+        nodeData, label, styleAttr));
+    edges.append(String.format("\"%s\" -> \"%s\";\n", 
+        nodeMap.get(parent), nodeData));
+  }
+  
+  private String getLabel(String nodeType, String data) {
+    StringBuffer label = new StringBuffer(nodeType);
+    if(nodeType.endsWith("Literal") || "DartIdentifier".equals(nodeType) 
+      || "DartClass".equals(nodeType) || "DartMethodDefinition".equals(nodeType)
+      || "DartVariable".equals(nodeType) || "DartField".equals(nodeType)
+      || "DartParameter".equals(nodeType) || nodeType.endsWith("Expression")) {
+      label.append(String.format("\\n%s",data.replaceAll("\"", "'")));

[zundel, 2011/11/15 14:49:54]

space after ,

[shauvik, 2011/11/15 23:53:14]

Done.

+    }
+    return label.toString();
+  }
+
+  private String getStyleAttr(String nodeType, DartNode node) {
+    StringBuffer style = new StringBuffer();
+    if(nodeType.endsWith("Literal") || "DartIdentifier".equals(nodeType)) {
+      style.append(", shape=box"); // OR style=filled, color=yellow
+    }else if("DartClass".equals(nodeType)) {
+      style.append(", shape=doubleoctagon");
+    }else if("DartMethodDefinition".equals(nodeType)) {
+      style.append(", color=blue");
+    }
+    return style.toString();
+  }
+
+  @Override
+  public void visitChildren(DartNode node) {

[zundel, 2011/11/15 14:49:54]

is this override necessary? 

[shauvik, 2011/11/15 23:53:14]

Done.

+    node.visitChildren(this);
+  }
+  
+  @Override
+  public Object visitUnit(DartUnit node) {
+    if(!isIgnored(node)){
+      String dotFilePath = outputDir + File.separator 
+          + currentUnit.getSource().getUri() + ".ast.dot";
+      makeParentDirs(dotFilePath);
+      try {
+        out = new FileWriter(new File(dotFilePath));
+      } catch (IOException e) {
+        e.printStackTrace();
+      }
+      visitChildren(node);
+    }
+    return null;
+  }
+
+}