Sync changes to previous chapters (#57)

Also fix broken links in README

3 files changed, 11 insertions, 17 deletions

diff --git a/chapter05/README.md b/chapter05/README.md
index b71597a0..434fcc5e 100644
--- a/chapter05/README.md
+++ b/chapter05/README.md
@@ -113,7 +113,7 @@ This involves following:
   updated to point to the `Phi` node.
 10. Finally, we set the `Region` node as the control token, and discard the duplicated `ScopeNode`.
 
-Implementation is in [`parseIf` method in `Parser`](https://github.com/SeaOfNodes/Simple/blob/main/chapter05/src/main/java/com/seaofnodes/simple/Parser.java#L146-L186).
+Implementation is in [`parseIf` method in `Parser`](https://github.com/SeaOfNodes/Simple/blob/main/chapter05/src/main/java/com/seaofnodes/simple/Parser.java#L149-L185).
 
 ## Operations on ScopeNodes
 
@@ -129,7 +129,7 @@ Our goals are:
 2) Make the new ScopeNode a user of all the bound nodes
 3) Ensure that the order of defs in the duplicate is the same to allow easy merging
 
-For implementation [see `scopeNode.dup()`](https://github.com/SeaOfNodes/Simple/blob/main/chapter05/src/main/java/com/seaofnodes/simple/node/ScopeNode.java#L99-L119)
+For implementation [see `scopeNode.dup()`](https://github.com/SeaOfNodes/Simple/blob/main/chapter05/src/main/java/com/seaofnodes/simple/node/ScopeNode.java#L142-L154)
 
 ### Merging two ScopeNodes
 
@@ -142,7 +142,7 @@ At the merge point we merge two ScopeNodes. The goals are:
 The merging logic takes advantage of that fact that the two ScopeNodes have the bound nodes in the same order in the list of inputs. This was ensured during duplicating the ScopeNode. 
 Although only the innermost occurrence of a name can have its binding changed, we scan all the nodes in our input list, and simply ignore ones where the binding has not changed.
 
-For implementation [see `ScopeNode.mergeScopes()`](https://github.com/SeaOfNodes/Simple/blob/main/chapter05/src/main/java/com/seaofnodes/simple/node/ScopeNode.java#L121-L136)
+For implementation [see `ScopeNode.mergeScopes()`](https://github.com/SeaOfNodes/Simple/blob/main/chapter05/src/main/java/com/seaofnodes/simple/node/ScopeNode.java#L164-L173)
 
 ## Example
 
diff --git a/chapter05/src/main/java/com/seaofnodes/simple/Parser.java b/chapter05/src/main/java/com/seaofnodes/simple/Parser.java
index 3de0e9b8..99d38686 100644
--- a/chapter05/src/main/java/com/seaofnodes/simple/Parser.java
+++ b/chapter05/src/main/java/com/seaofnodes/simple/Parser.java
@@ -13,7 +13,6 @@ import java.util.*;
  * This is a simple recursive descent parser. All lexical analysis is done here as well.
  */
 public class Parser {
-
   
     /**
      * A Global Static, unique to each compilation.  This is a public, so we
@@ -88,14 +87,14 @@ public class Parser {
 
     public StopNode parse() { return parse(false); }
     public StopNode parse(boolean show) {
-	    _xScopes.push(_scope);
+        _xScopes.push(_scope);
         // Enter a new scope for the initial control and arguments
         _scope.push();
         _scope.define(ScopeNode.CTRL, new ProjNode(START, 0, ScopeNode.CTRL).peephole());
         _scope.define(ScopeNode.ARG0, new ProjNode(START, 1, ScopeNode.ARG0).peephole());
         parseBlock();
         _scope.pop();
-		_xScopes.pop();
+        _xScopes.pop();
         if (!_lexer.isEOF()) throw error("Syntax error, unexpected " + _lexer.getAnyNextToken());
         STOP.peephole();
         if( show ) showGraph();
@@ -152,7 +151,7 @@ public class Parser {
         // Parse predicate
         var pred = require(parseExpression(), ")");
         // IfNode takes current control and predicate
-        IfNode ifNode = (IfNode)new IfNode(ctrl(), pred).peephole();
+        IfNode ifNode = (IfNode)new IfNode(ctrl(), pred).<IfNode>keep().peephole();
         // Setup projection nodes
         Node ifT = new ProjNode(ifNode, 0, "True" ).peephole();
         Node ifF = new ProjNode(ifNode, 1, "False").peephole();
@@ -268,10 +267,10 @@ public class Parser {
         var lhs = parseAddition();
         if (match("==")) return new BoolNode.EQ(lhs, parseComparison()).peephole();
         if (match("!=")) return new NotNode(new BoolNode.EQ(lhs, parseComparison()).peephole()).peephole();
-        if (match("<" )) return new BoolNode.LT(lhs, parseComparison()).peephole();
         if (match("<=")) return new BoolNode.LE(lhs, parseComparison()).peephole();
-        if (match(">" )) return new BoolNode.LT(parseComparison(), lhs).peephole();
+        if (match("<" )) return new BoolNode.LT(lhs, parseComparison()).peephole();
         if (match(">=")) return new BoolNode.LE(parseComparison(), lhs).peephole();
+        if (match(">" )) return new BoolNode.LT(parseComparison(), lhs).peephole();
         return lhs;
     }
 
diff --git a/chapter05/src/main/java/com/seaofnodes/simple/node/Node.java b/chapter05/src/main/java/com/seaofnodes/simple/node/Node.java
index 3b841d8c..810f931b 100644
--- a/chapter05/src/main/java/com/seaofnodes/simple/node/Node.java
+++ b/chapter05/src/main/java/com/seaofnodes/simple/node/Node.java
@@ -81,10 +81,7 @@ public abstract class Node {
     // line (because this is what a debugger typically displays by default) and
     // has to be robust with broken graph/nodes.
     @Override
-    public final String toString() {
-        // TODO: This needs a lot of work
-        return print();
-    }
+    public final String toString() {  return print(); }
 
     // This is a *deep* print.  This version will fail on cycles, which we will
     // correct later when we can parse programs with loops.  We print with a
@@ -121,8 +118,6 @@ public abstract class Node {
 
     public boolean isCFG() { return false; }
   
-
-    
     /**
      * Change a <em>def</em> into a Node.  Keeps the edges correct, by removing
      * the corresponding <em>use->def</em> edge.  This may make the original
@@ -180,11 +175,11 @@ public abstract class Node {
     // Error is 'use' does not exist; ok for 'use' to be null.
     protected boolean delUse( Node use ) {
         Utils.del(_outputs, Utils.find(_outputs, use));
-        return _outputs.size() == 0;
+        return _outputs.isEmpty();
     }
 
     // Shortcut for "popping" n nodes.  A "pop" is basically a
-    // set_def(last,null) followed by lowering the nIns() count.
+    // setDef(last,null) followed by lowering the nIns() count.
     void popN(int n) {
         for( int i=0; i<n; i++ ) {
             Node old_def = _inputs.removeLast();