Determine first/last popped nodes statically in parser new methods

This saves having to update the firstPopped/lastPopped instance
variables at runtime on every pop call.

src/main/java/org/sablecc/sablecc/GenerateAlternativeCodeForParser.java

@@ -30,6 +30,8 @@ public class GenerateAlternativeCodeForParser extends DepthFirstAdapter
   private LinkedList listSimpleTermTransform;
   private Map<Node, String> simpleTermOrsimpleListTermTypes;
 
+  private int popCount;
+
   GenerateAlternativeCodeForParser(File pkgDir, String aParsedAltName,
                                    String raParsedAltName,
                                    BufferedWriter file,
@@ -52,6 +54,13 @@ public class GenerateAlternativeCodeForParser extends DepthFirstAdapter
     this.macros = macros;
     this.listSimpleTermTransform = listSimpleTermTransform;
     this.simpleTermOrsimpleListTermTypes = simpleTermOrsimpleListTermTypes;
+
+    this.popCount = 0;
+  }
+
+  @Override
+  public void caseAElem(final AElem node) {
+    popCount++;
   }
 
   @Override
@@ -134,6 +143,10 @@ public class GenerateAlternativeCodeForParser extends DepthFirstAdapter
         macros.apply(file, "ParserNewBodyListAdd", new String[] {type_name, "" + position});
 
       }
+      if (popCount > 0) {
+        // The nodeArrayList variables are numbered starting at 1, so the first popped variable has the number popCount and not popCount-1.
+        macros.apply(file, "ParserNewCheck", new String[] {String.valueOf(popCount)});
+      }
       macros.apply(file, "ParserNewTail");
     }
     catch(IOException e)

src/main/resources/org/sablecc/sablecc/parser.txt

@@ -39,9 +39,6 @@ public class Parser implements IParser
     private final static int ACCEPT = 2;
     private final static int ERROR = 3;
 
-    private List<Object> firstPopped = null;
-    private List<Object> lastPopped = null;
-
     public Parser(Lexer lexer)
     {
         this.lexer = lexer;
@@ -252,13 +249,7 @@ Macro:ParserCommon
 
     private List<Object> pop()
     {
-        List<Object> list = this.stack.previous().nodes;
-        if (this.firstPopped == null) {
-            this.firstPopped = list;
-        } else {
-            this.lastPopped = list;
-        }
-        return list;
+        return this.stack.previous().nodes;
     }
 
     private int index(Switchable token)
@@ -375,8 +366,6 @@ Macro:ParserNewHeader
 
     private List<Object> new$0$() /* reduce $1$ */
     {
-        this.firstPopped = null;
-        this.lastPopped = null;
         final boolean addElementsToNewList = addElementsFromListToNewList("$1$");
         List<Object> nodeList = new ArrayList<>();
 
@@ -470,8 +459,12 @@ Macro:ParserNewBodyListAdd
 
 $
 
+Macro:ParserNewCheck
+        checkResult(nodeList.get(0), nodeArrayList1, nodeArrayList$0$);
+
+$
+
 Macro:ParserNewTail
-        checkResult(nodeList.get(0), this.lastPopped, this.firstPopped);
         return nodeList;
     }