Progress JSView

Larger programs, better layouts.
Missing e.g. types, & program text & the inter peeps phase

11 files changed, 429 insertions, 69 deletions

diff --git a/chapter18/src/main/java/com/seaofnodes/simple/Ary.java b/chapter18/src/main/java/com/seaofnodes/simple/Ary.java
index 8654d41e..d37c284f 100644
--- a/chapter18/src/main/java/com/seaofnodes/simple/Ary.java
+++ b/chapter18/src/main/java/com/seaofnodes/simple/Ary.java
@@ -57,18 +57,6 @@ public class Ary<E> extends AbstractList<E> implements List<E> {
         return true;
     }
 
-    ///** Slow, linear-time, element insert.  Preserves order.
-    // *  @param i index to insert at, between 0 and _len inclusive.
-    // *  @param e Element to insert
-    // */
-    //public void insert( int i, E e ) {
-    //    if( i < 0 || i>_len )
-    //        throw new ArrayIndexOutOfBoundsException(""+i+" >= "+_len);
-    //    if( _len >= _es.length ) _es = Arrays.copyOf(_es,Math.max(1,_es.length<<1));
-    //    System.arraycopy(_es,i,_es,i+1,(_len++)-i);
-    //    _es[i] = e;
-    //}
-
     /** Fast, constant-time, element removal.  Does not preserve order
      *  @param i element to be removed
      *  @return element removed */
diff --git a/chapter18/src/main/java/com/seaofnodes/simple/GraphVisualizer.java b/chapter18/src/main/java/com/seaofnodes/simple/GraphVisualizer.java
index ec326a6f..eb8d8e23 100644
--- a/chapter18/src/main/java/com/seaofnodes/simple/GraphVisualizer.java
+++ b/chapter18/src/main/java/com/seaofnodes/simple/GraphVisualizer.java
@@ -27,7 +27,7 @@ public class GraphVisualizer {
 
         // Since the graph has cycles, we need to create a flat list of all the
         // nodes in the graph.
-        Collection<Node> all = findAll(stop, scope);
+        Collection<Node> all = findAll(xScopes, stop, scope);
         StringBuilder sb = new StringBuilder();
         sb.append("digraph chapter18 {\n");
         sb.append("/*\n");
@@ -263,20 +263,19 @@ public class GraphVisualizer {
     /**
      * Finds all nodes in the graph.
      */
-    private Collection<Node> findAll(Node stop, Node scope) {
+    public static Collection<Node> findAll(Stack<ScopeNode> ss, Node... ns) {
         final HashMap<Integer, Node> all = new HashMap<>();
-        for( Node n : stop._inputs )
+        for( Node n : ns )
+            walk(all, n);
+        for( Node n : ss )
             walk(all, n);
-        if( scope != null )
-            for( Node n : scope._inputs )
-                walk(all, n);
         return all.values();
     }
 
     /**
      * Walk a subgraph and populate distinct nodes in the all list.
      */
-    private void walk(HashMap<Integer,Node> all, Node n) {
+    private static void walk(HashMap<Integer,Node> all, Node n) {
         if(n == null ) return;
         if (all.get(n._nid) != null) return; // Been there, done that
         all.put(n._nid, n);
diff --git a/chapter18/src/main/java/com/seaofnodes/simple/JSViewer.java b/chapter18/src/main/java/com/seaofnodes/simple/JSViewer.java
index da361afa..48776fd5 100644
--- a/chapter18/src/main/java/com/seaofnodes/simple/JSViewer.java
+++ b/chapter18/src/main/java/com/seaofnodes/simple/JSViewer.java
@@ -1,50 +1,331 @@
 package com.seaofnodes.simple;
 
+import com.seaofnodes.simple.node.*;
+
 import java.nio.file.Paths;
+import java.io.IOException;
+import java.util.Stack;
+import java.util.Collection;
 
-public class JSViewer {
+public class JSViewer implements AutoCloseable {
+    // Display programs in an endless loop
     public static void main( String[] args ) throws Exception {
-        // Launch server
-        try( SimpleWebSocket server = new SimpleWebSocket(Paths.get("docs/index.html").toUri(),12345) ) {
-            int N=0;
-            while( true ) {
-                String src = server.get();
-                if( src==null || src.equals("null") )
-                    break;
+        try(var js = new JSViewer()) {
+            js.run();
+        }
+    }
+
+    static boolean SHOW;
+
+    // WebSocket to the browser for display
+    static SimpleWebSocket SERVER;
+
+    static int N;               // Dot frames
+    static Parser P;            //
+    static StopNode STOP;       //
+
+    JSViewer() throws Exception {
+        // Launch server; hand shake
+        SERVER = new SimpleWebSocket(Paths.get("docs/index.html").toUri(),12345) ;
+    }
+
+    void run( ) throws Exception {
+        while( true ) {
+            String src = SERVER.get();
+            switch( src ) {
+            case null: return;
+            case "null": return;
+            case "+": break;    // Client requests more frames, but we send them all anyways
+            default:
                 System.out.println(src);
-                // Client requests another frame
-                if( src.charAt(0)=='+' ) {
-                    if( N<2 ) {
-                        StringBuilder sb = new StringBuilder();
-                        sb.append("digraph jsviewer_1 {\n");
-                        sb.append("\tnode [shape=circle, style=filled];\n");
-                        sb.append("\tSRC [label=\"").append("next frame").append("\", shape=oval];\n");
-                        sb.append("}");
-                        server.put(sb.toString());
-                        System.out.println("Sent graph "+N);
-                        N++;
-                    } else {
-                        // no more frames, send nothing
+                try {
+                    N=0;
+                    // Use parser scope, xscope when building views
+                    P = new Parser(src);
+                    STOP = P.STOP;
+                    SHOW = true;
+                    show();
+                    // Parse program, generating views at every parse point
+                    P.parse();
+                    // No longer user parse internal state when building views
+                    P = null;
+
+
+
+                    // Catch and ignore Parser errors
+                } catch(RuntimeException re) {
+                } finally {
+                    SHOW = false;
+                    SERVER.put("#"); // Final frame
+                }
+                break;
+            }
+        }
+    }
+
+    @Override public void close() throws IOException {
+        SERVER.close();
+        SERVER=null;
+    }
+
+    public static void show() { if( SERVER!=null && SHOW ) _show(); }
+    private static void _show() {
+        Collection<Node> all = GraphVisualizer.findAll(P==null ? null : P._xScopes, STOP, P==null ? null : P._scope);
+        SB sb = new SB();
+        sb.p("digraph view_").p(N++).p(" {\n").ii();
+
+        // To keep the Scopes below the graph and pointing up into the graph we
+        // need to group the Nodes in a subgraph cluster, and the scopes into a
+        // different subgraph cluster.  THEN we can draw edges between the
+        // scopes and nodes.  If we try to cross subgraph cluster borders while
+        // still making the subgraphs DOT gets confused.
+        sb.i().p("rankdir=BT;\n"); // Force Nodes before Scopes
+
+        // CNC - turned off Apr/8/2024, gives more flex in the layout and
+        // removes some of the more ludicrous layout choices.
+        // Preserve node input order
+        //sb.append("ordering=\"in\";\n");
+
+        // Merge multiple edges hitting the same node.  Makes common shared
+        // nodes much prettier to look at.
+        sb.i().p("concentrate=\"true\";\n");
+
+        // Force nested scopes to order
+        sb.i().p("compound=\"true\";\n");
+
+        // Just the Nodes first, in a cluster no edges
+        nodes(sb, all);
+
+        // Now the scopes, in a cluster no edges
+        if( P!=null )
+            for( ScopeNode xscope : P._xScopes )
+                if( !xscope.isDead() )
+                    scope( sb, xscope );
+
+        // Walk the Node edges
+        nodeEdges(sb, P!=null && !P._xScopes.empty() ? P._xScopes.peek() : null, all);
+
+        // Walk the active Scope edges
+        if( P!=null )
+            for( ScopeNode xscope : P._xScopes )
+                if( !xscope.isDead() )
+                    scopeEdges( sb, xscope );
+
+
+        sb.p("}\n").di();
+        // Tell client another DOT frame
+        String dot = sb.toString();
+        System.out.println(dot);
+        try {
+            SERVER.put(dot);
+        } catch( IOException ioe ) {
+            try { SERVER.close();} catch( IOException ignored ){}
+        }
+    }
+
+
+
+    private static void nodes(SB sb, Collection<Node> all) {
+        // Just the Nodes first, in a cluster no edges
+        sb.i().p("subgraph cluster_Nodes {\n").ii(); // Magic "cluster_" in the subgraph name
+        for (Node n : all) {
+            if( n instanceof ProjNode || n instanceof CProjNode || n instanceof ScopeMinNode || n==Parser.XCTRL )
+                continue; // Do not emit, rolled into MultiNode or Scope cluster already
+            sb.i().p(n.uniqueName()).p(" [ ");
+            String lab = n.glabel();
+            if( n instanceof MultiNode ) {
+                // Make a box with the MultiNode on top, and all the projections on the bottom
+                sb.    p("shape=plaintext label=<\n").ii();
+                sb.i().p("<TABLE BORDER=\"0\" CELLBORDER=\"1\" CELLSPACING=\"0\" CELLPADDING=\"4\">\n");
+                // Row over single cell for node label
+                cell(sb.i().p("<TR>"), lab, null, true, false).p("</TR>\n");
+                // Row over single cell, for nested table
+                sb.i().p("<TR><TD>\n").ii();
+                sb.i().p("<TABLE BORDER=\"0\" CELLBORDER=\"1\" CELLSPACING=\"0\">").p("\n");
+                sb.i().p("<TR>");
+                n._outputs.sort((x,y) -> x instanceof ProjNode xp && y instanceof ProjNode yp ? (xp._idx - yp._idx) : ((x==null ? 99999 : x._nid) - (y==null ? 99999 : y._nid)));
+                boolean empty_row=true;
+                for( Node use : n._outputs )
+                    if( use instanceof MultiUse muse ) {
+                        cell(sb,use.glabel(),"p"+muse.idx(),use instanceof CFGNode,use.isMem());
+                        empty_row=false;
                     }
-                } else {
+                // At least one cell on row
+                if( empty_row )
+                    cell(sb,"",null,false,false);
+                sb.    p("</TR>").p("\n");
+                sb.i().p("</TABLE>").p("\n").di();
+                sb.i().p("</TD></TR>\n");
+                sb.i().p("</TABLE>>\n").di();
+                sb.i().p("];\n");
 
-                    StringBuilder sb = new StringBuilder();
-                    sb.append("digraph jsviewer_0 {\n");
-                    sb.append("\tnode [shape=circle, style=filled];\n");
-                    sb.append("\tSRC [label=\"").append(src).append("\", shape=oval];\n");
-                    sb.append("}");
-                    server.put(sb.toString());
-                    System.out.println("Sent graph "+N);
-                    N++;
+            } else {
+                // control nodes have box shape
+                // other nodes are ellipses, i.e. default shape
+                if( n instanceof CFGNode ) sb.p("shape=box style=filled fillcolor=yellow ");
+                else if (n instanceof PhiNode) sb.p("style=filled fillcolor=lightyellow ");
+                sb.p("label=\"").p(lab).p("\" ];\n");
+            }
+        }
+        // Force Region & Phis to line up
+        for (Node n : all) {
+            if (n instanceof RegionNode region) {
+                sb.i().p("{ rank=same; ");
+                sb.p(region.uniqueName()).p(";");
+                for (Node phi : region._outputs)
+                    if (phi instanceof PhiNode) sb.p(phi.uniqueName()).p(";");
+                sb.p("}\n");
+            }
+        }
+        sb.di().i().p("}").nl();     // End Node cluster
+    }
+
+    // Build a nested scope display, walking the _prev edge
+    private static void scope( SB sb, ScopeNode scope ) {
+        sb.i().p("node [shape=plaintext];\n");
+        int last = scope.nIns();
+        int max = scope._lexSize.size();
+        for( int i = 0; i < max; i++ ) {
+            int level = max-i-1;
+            String scopeName = makeScopeName(scope, level);
+            sb.i().p("subgraph cluster_").p(scopeName).p(" {\n").ii(); // Magic "cluster_" in the subgraph name
+            sb.i().p(scopeName).p(" [label=<\n").ii();
+            sb.i().p("<TABLE BORDER=\"0\" CELLBORDER=\"1\" CELLSPACING=\"0\">\n");
+            // Add the scope level
+            sb.i().p("<TR><TD BGCOLOR=\"cyan\">").p(level).p("</TD>");
+            int lexStart=scope._lexSize.at(level);
+            // Special for memory ScopeMinNode
+            ScopeMinNode n = scope.nIns()>1 ? scope.mem() : null;
+            if( level==0 && n!=null && n.nIns()>2 ) {
+                sb.    p("<TD BGCOLOR=\"blue\" BORDER=0 colspan=\"").p(last-lexStart-1).p("\">\n");
+                sb.i().p("\t<TABLE><TR>");
+                for( int m=2; m<n.nIns(); m++ ) {
+                    sb.p("<TD>").p(m).p("</TD>");
+                    throw Utils.TODO(); // Need port names for edges
                 }
+                sb.p("</TR></TABLE>\n");
+                sb.i().p("</TD>");
+            }
+            sb.    p("</TR>\n"); // End scope level
+            sb.i().p("<TR>\n");
+            for( int j=lexStart; j<last; j++ ) {
+                var v = scope._vars.at(j);
+                cell(sb.i(),v._name,makePortName(scopeName, v._name),j==0,j==1).nl();
+            }
+            last = lexStart;
+            sb.i().p("</TR>\n");
+            sb.i().p("</TABLE>>];\n").di();
+        }
+        // Scope clusters nest, so the graphics shows the nested scopes, so
+        // they are not closed as they are printed; so they just keep nesting.
+        // We close them all at once here.
+        for( int i=0; i<max; i++ )
+            sb.di().i().p("}\n");
+    }
 
-                //// Client reset, send new program
-                //server.put("!");
+    // Append a cell, with color
+    private static SB cell(SB sb, String text, String port, boolean isCFG, boolean isMem) {
+        sb.p("<TD ");
+        if( port!=null )  sb.p("PORT=\"").p(port).p("\"");
+        if( isCFG ) sb.p(" BGCOLOR=\"yellow\"");
+        if( isMem ) sb.p(" BGCOLOR=\"blue\"");
+        sb.p(">");
+        if( isMem ) sb.p("<FONT color=\"white\">");
+        sb.p(text);
+        if( isMem ) sb.p("</FONT>");
+        sb.p("</TD>");
+        return sb;
+    }
+
+    private static String makeScopeName(ScopeNode sn, int level) { return sn.uniqueName() + "_" + level; }
+    private static String makePortName(String scopeName, String varName) { return scopeName + "_" + varName; }
+
+    // Walk the node edges
+    private static void nodeEdges(SB sb, ScopeNode scope, Collection<Node> all) {
+        // All them edge labels
+        String scopeName = scope!=null ? makeScopeName(scope, 0) : null;
+        sb.i().p("edge [ fontname=Helvetica, fontsize=8 ];\n");
+        for( Node n : all ) {
+            // Do not display the Constant->Start edge;
+            if( n instanceof ConstantNode ||
+                n instanceof XCtrlNode ||
+                // ProjNodes handled by Multi;
+                n instanceof ProjNode ||
+                n instanceof CProjNode ||
+                // ScopeNodes are done separately
+                n instanceof ScopeNode ||
+                n instanceof ScopeMinNode
+                )
+                continue;
+            if( n.isDead() )
+                throw Utils.TODO();
+            // Normal edges
+            for( int i=0; i<n.nIns(); i++ ) {
+                Node def = n.in(i);
+                if( def==null ) continue;
+                sb.i().p(n.uniqueName()).p(" -> ");
+                if( n instanceof PhiNode && def instanceof RegionNode ) {
+                    // Draw a dotted use->def edge from Phi to Region.
+                    sb.p(def.uniqueName());
+                    sb.p(" [style=dotted taillabel=").p(i).p("];\n");
+                } else {
+                    // Most edges land here use->def
+                    if( def instanceof CProjNode proj ) {
+                        String mname = proj.ctrl().uniqueName();
+                        sb.p(mname).p(":p").p(proj._idx);
+                    } else if( def instanceof ProjNode proj ) {
+                        String mname = proj.in(0).uniqueName();
+                        sb.p(mname).p(":p").p(proj._idx);
+                    } else sb.p(def.uniqueName());
+                    // Number edges, so we can see how they track
+                    sb.p("[taillabel=").p(i);
+                    // The edge from New to ctrl is just for anchoring the New
+                    if ( n instanceof NewNode )
+                        sb.p(" color=green");
+                    // control edges are colored red
+                    else if( def instanceof CFGNode )
+                        sb.p(" color=red");
+                    else if( def.isMem() )
+                        sb.p(" color=blue");
+                    // Backedges do not add a ranking constraint
+                    if( i==2 && (n instanceof PhiNode || n instanceof LoopNode) )
+                        sb.p(" constraint=false");
+                    sb.p("];\n");
+                }
+            }
+
+            // Bonus edge if hooked by parser
+            if( (n.iskeep() || n.isUnused()) && scopeName != null ) {
+                sb.i().p(scopeName).p(" -> ").p(n.uniqueName()).p(" [ stype=dotted color=grey]\n");
             }
-            System.out.println("Client requested shutdown");
-            server.close();
         }
+    }
 
+    // Walk the scope edges
+    private static void scopeEdges( SB sb, ScopeNode scope ) {
+        sb.i().p("edge [style=dashed color=cornflowerblue];\n");
+        int level=0;
+        for( var v : scope._vars ) {
+            if( v._idx==1 ) continue; // Memory done seperately
+            Node def = scope.in(v._idx);
+            while( def instanceof ScopeNode lazy )
+                def = lazy.in(v._idx);
+            if( def==null ) continue;
+            while( level < scope._lexSize.size() && v._idx >= scope._lexSize.at(level) )
+                level++;
+            String scopeName = makeScopeName(scope, level-1);
+            sb.i()
+                .p(scopeName).p(":")
+                .p('"').p(makePortName(scopeName, v._name)).p('"') // wrap port name with quotes because $ctrl is not valid unquoted
+                .p(" -> ");
+            if( def instanceof CProjNode proj ) {
+                sb.p(def.in(0).uniqueName()).p(":p").p(proj._idx);
+            } else if( def instanceof ProjNode proj ) {
+                sb.p(def.in(0).uniqueName()).p(":p").p(proj._idx);
+            } else sb.p(def.uniqueName());
+            sb.p(";\n");
+        }
     }
 
+
 }
diff --git a/chapter18/src/main/java/com/seaofnodes/simple/Parser.java b/chapter18/src/main/java/com/seaofnodes/simple/Parser.java
index 94575559..123841e8 100644
--- a/chapter18/src/main/java/com/seaofnodes/simple/Parser.java
+++ b/chapter18/src/main/java/com/seaofnodes/simple/Parser.java
@@ -82,7 +82,6 @@ public class Parser {
             add("while");
         }};
 
-
     /**
      * We clone ScopeNodes when control flows branch; it is useful to have
      * a list of all active ScopeNodes for purposes of visualization of the SoN graph
@@ -100,6 +99,7 @@ public class Parser {
     // Mapping from a type name to the constructor for a Type.
     public final HashMap<String, StructNode> INITS;
 
+    public Parser(String source) { this(source, TypeInteger.BOT); }
 
     public Parser(String source, TypeInteger arg) {
         Node.reset();
@@ -117,10 +117,6 @@ public class Parser {
         INITS = new HashMap<>();
     }
 
-    public Parser(String source) {
-        this(source, TypeInteger.BOT);
-    }
-
     @Override
     public String toString() { return _lexer.toString(); }
 
@@ -162,6 +158,7 @@ public class Parser {
         mem.addDef(                                           new  ProjNode(START, 1, ScopeNode.MEM0).peephole());
         _scope.define(ScopeNode.MEM0, TypeMem.TOP    , false, mem                                    .peephole());
         _scope.define(ScopeNode.ARG0, TypeInteger.BOT, false, new  ProjNode(START, 2, ScopeNode.ARG0).peephole());
+        JSViewer.show();
 
         // Parse whole program
         parseBlock(false);
diff --git a/chapter18/src/main/java/com/seaofnodes/simple/SB.java b/chapter18/src/main/java/com/seaofnodes/simple/SB.java
new file mode 100644
index 00000000..6f5a29ee
--- /dev/null
+++ b/chapter18/src/main/java/com/seaofnodes/simple/SB.java
@@ -0,0 +1,74 @@
+package com.seaofnodes.simple;
+
+/** Tight/tiny StringBuilder wrapper.
+ *  Short short names on purpose; so they don't obscure the printing.
+ *  Can't believe this wasn't done long, long ago. */
+public final class SB {
+  private final StringBuilder _sb;
+  private int _indent = 0;
+  public SB(        ) { _sb = new StringBuilder( ); }
+  public SB(String s) { _sb = new StringBuilder(s); }
+  public SB p( String s ) { _sb.append(s); return this; }
+  public SB p( float  s ) {
+    if( Float.isNaN(s) )
+      _sb.append( "Float.NaN");
+    else if( Float.isInfinite(s) ) {
+      _sb.append(s > 0 ? "Float.POSITIVE_INFINITY" : "Float.NEGATIVE_INFINITY");
+    } else _sb.append(s);
+    return this;
+  }
+  public SB p( double s ) {
+    if( Double.isNaN(s) )
+      _sb.append("Double.NaN");
+    else if( Double.isInfinite(s) ) {
+      _sb.append(s > 0 ? "Double.POSITIVE_INFINITY" : "Double.NEGATIVE_INFINITY");
+    } else _sb.append(s);
+    return this;
+  }
+  public SB p( char   s ) { _sb.append(s); return this; }
+  public SB p( int    s ) { _sb.append(s); return this; }
+  public SB p( long   s ) { _sb.append(s); return this; }
+  public SB p( boolean s) { _sb.append(s); return this; }
+  // Not spelled "p" on purpose: too easy to accidentally say "p(1.0)" and
+  // suddenly call the autoboxed version.
+  public SB pobj( Object s ) { _sb.append(s.toString()); return this; }
+  public SB i( int d ) { for( int i=0; i<d+_indent; i++ ) p("  "); return this; }
+  public SB i( ) { return i(0); }
+  public SB ip(String s) { return i().p(s); }
+  public SB s() { _sb.append(' '); return this; }
+
+  // Increase indentation
+  public SB ii( int i) { _indent += i; return this; }
+  public SB ii() { return ii(1); }
+  // Decrease indentation
+  public SB di( int i) { _indent -= i; return this; }
+  public SB di() { return di(1); }
+
+  public SB nl( ) { return p(System.lineSeparator()); }
+  // Last printed a nl
+  public boolean was_nl() {
+    int len = _sb.length();
+    String nl = System.lineSeparator();
+    int nlen = nl.length();
+    if( len < nlen ) return false;
+    for( int i=0; i<nlen; i++ )
+      if( _sb.charAt(len-nlen+i)!=nl.charAt(i) )
+        return false;
+    return true;
+  }
+
+  // Delete last char.  Useful when doing string-joins and JSON printing and an
+  // extra separater char needs to be removed:
+  //
+  //   sb.p('[');
+  //   for( Foo foo : foos )
+  //     sb.p(foo).p(',');
+  //   sb.unchar().p(']');  // remove extra trailing comma
+  //
+  public SB unchar() { return unchar(1); }
+  public SB unchar(int x) { _sb.setLength(_sb.length()-x); return this; }
+
+  public SB clear() { _sb.setLength(0); return this; }
+  public int len() { return _sb.length(); }
+  @Override public String toString() { return _sb.toString(); }
+}
diff --git a/chapter18/src/main/java/com/seaofnodes/simple/SimpleWebSocket.java b/chapter18/src/main/java/com/seaofnodes/simple/SimpleWebSocket.java
index 86ae7c9b..114bfddd 100644
--- a/chapter18/src/main/java/com/seaofnodes/simple/SimpleWebSocket.java
+++ b/chapter18/src/main/java/com/seaofnodes/simple/SimpleWebSocket.java
@@ -60,7 +60,7 @@ class SimpleWebSocket extends ServerSocket {
         _len = _in.read(_ins);  _x=0;
         int op = rawget();
         if( (op&0x80)!=0x80 ) // FIN bit not set?
-            throw Utils.TODO("Multi-part from client: "+op); // Multi-part message
+            throw Utils.TODO("Multi-part from client: "+op); // Multipart message
         op &= 0x7F;         // Strip FIN bit
         switch( op&15) {
         case 1: {
@@ -89,9 +89,20 @@ class SimpleWebSocket extends ServerSocket {
 
     // Classic put to browser client.  No encoding.
     public void put(String msg) throws IOException {
-        assert msg.length() < 125;
-        _out.write(129); // FIN
-        _out.write(msg.length());
+        int len = msg.length();
+        if( len <= 125 ) {
+            _out.write(129); // FIN, opcode 1 - whole text message
+            _out.write(len);
+            for( int i=0; i<msg.length(); i++ )
+                _out.write(msg.charAt(i));
+            return;
+        }
+        if( len > 65535 )
+            throw Utils.TODO("MOAR LENGTH");
+        _out.write(129);        // FIN, opcode 1 - whole text message
+        _out.write(126);        // Length is 16b
+        _out.write(len>>>8);
+        _out.write(len&255);
         for( int i=0; i<msg.length(); i++ )
             _out.write(msg.charAt(i));
     }
diff --git a/chapter18/src/main/java/com/seaofnodes/simple/node/CProjNode.java b/chapter18/src/main/java/com/seaofnodes/simple/node/CProjNode.java
index d2f1bbe1..0b9d89d2 100644
--- a/chapter18/src/main/java/com/seaofnodes/simple/node/CProjNode.java
+++ b/chapter18/src/main/java/com/seaofnodes/simple/node/CProjNode.java
@@ -6,7 +6,7 @@ import com.seaofnodes.simple.type.TypeMem;
 import com.seaofnodes.simple.type.TypeTuple;
 import java.util.BitSet;
 
-public class CProjNode extends CFGNode {
+public class CProjNode extends CFGNode implements MultiUse {
 
     // Which slice of the incoming multipart value
     public final int _idx;
@@ -21,6 +21,7 @@ public class CProjNode extends CFGNode {
     }
 
     @Override public String label() { return _label; }
+    @Override public int idx() { return _idx; }
 
     @Override StringBuilder _print1(StringBuilder sb, BitSet visited) { return sb.append(_label); }
 
diff --git a/chapter18/src/main/java/com/seaofnodes/simple/node/MultiUse.java b/chapter18/src/main/java/com/seaofnodes/simple/node/MultiUse.java
new file mode 100644
index 00000000..e4548dfd
--- /dev/null
+++ b/chapter18/src/main/java/com/seaofnodes/simple/node/MultiUse.java
@@ -0,0 +1,3 @@
+package com.seaofnodes.simple.node;
+
+public interface MultiUse { abstract int idx(); }
diff --git a/chapter18/src/main/java/com/seaofnodes/simple/node/Node.java b/chapter18/src/main/java/com/seaofnodes/simple/node/Node.java
index 3827fdac..040e3a0e 100644
--- a/chapter18/src/main/java/com/seaofnodes/simple/node/Node.java
+++ b/chapter18/src/main/java/com/seaofnodes/simple/node/Node.java
@@ -1,9 +1,6 @@
 package com.seaofnodes.simple.node;
 
-import com.seaofnodes.simple.Ary;
-import com.seaofnodes.simple.IRPrinter;
-import com.seaofnodes.simple.IterPeeps;
-import com.seaofnodes.simple.Utils;
+import com.seaofnodes.simple.*;
 import com.seaofnodes.simple.type.Type;
 import com.seaofnodes.simple.type.TypeFloat;
 import java.util.*;
@@ -306,7 +303,7 @@ public abstract class Node implements OutNode {
             return this;        // Peephole optimizations turned off
         }
         Node n = peepholeOpt();
-        return n==null ? this : deadCodeElim(n.peephole()); // Cannot return null for no-progress
+        return n==null ? this : deadCodeElim(n._nid >= _nid ? n.peephole() : n); // Cannot return null for no-progress
     }
 
     /**
@@ -328,6 +325,13 @@ public abstract class Node implements OutNode {
      * </ul>
      */
     public final Node peepholeOpt( ) {
+        JSViewer.show();
+        Node n = _peepholeOpt();
+        if( n==null ) return null;
+        JSViewer.show();
+        return n;
+    }
+    private final Node _peepholeOpt( ) {
         ITER_CNT++;
         // Compute initial or improved Type
         Type old = setType(compute());
diff --git a/chapter18/src/main/java/com/seaofnodes/simple/node/ProjNode.java b/chapter18/src/main/java/com/seaofnodes/simple/node/ProjNode.java
index 73c1fa15..525b5df0 100644
--- a/chapter18/src/main/java/com/seaofnodes/simple/node/ProjNode.java
+++ b/chapter18/src/main/java/com/seaofnodes/simple/node/ProjNode.java
@@ -6,7 +6,7 @@ import com.seaofnodes.simple.type.TypeTuple;
 
 import java.util.BitSet;
 
-public class ProjNode extends Node {
+public class ProjNode extends Node implements MultiUse {
 
     // Which slice of the incoming multipart value
     public final int _idx;
@@ -21,6 +21,7 @@ public class ProjNode extends Node {
     }
 
     @Override public String label() { return _label; }
+    @Override public int idx() { return _idx; }
 
     @Override
     StringBuilder _print1(StringBuilder sb, BitSet visited) { return sb.append(_label); }
diff --git a/chapter18/src/main/java/com/seaofnodes/simple/node/StopNode.java b/chapter18/src/main/java/com/seaofnodes/simple/node/StopNode.java
index 867225cb..269c2f6c 100644
--- a/chapter18/src/main/java/com/seaofnodes/simple/node/StopNode.java
+++ b/chapter18/src/main/java/com/seaofnodes/simple/node/StopNode.java
@@ -15,6 +15,7 @@ public class StopNode extends CFGNode {
     public StopNode(String src) {
         super();
         _src = src;
+        _type = compute();
     }
 
     @Override