Allow pre-inc/dec on variables

4 files changed, 16 insertions, 6 deletions

diff --git a/chapter17/src/test/java/com/seaofnodes/simple/BrainFuckTest.java b/chapter17/src/test/java/com/seaofnodes/simple/BrainFuckTest.java
index 28c3477c..0c2509bf 100644
--- a/chapter17/src/test/java/com/seaofnodes/simple/BrainFuckTest.java
+++ b/chapter17/src/test/java/com/seaofnodes/simple/BrainFuckTest.java
@@ -48,8 +48,7 @@ for( int pc = 0; pc < program#; pc++ ) {
     } else if (command == 91) {
         if (data[d] == 0) {
             for( var d = 1; d > 0; ) {
-                pc++;
-                command = program[pc];
+                command = program[++pc];
                 if (command == 91) d++;
                 if (command == 93) d--;
             }
@@ -57,8 +56,7 @@ for( int pc = 0; pc < program#; pc++ ) {
     } else if (command == 93) {
         if (data[d]) {
             for( var d = 1; d > 0; ) {
-                pc--;
-                command = program[pc];
+                command = program[--pc];
                 if (command == 93) d++;
                 if (command == 91) d--;
             }
diff --git a/chapter17/src/test/java/com/seaofnodes/simple/Chapter08Test.java b/chapter17/src/test/java/com/seaofnodes/simple/Chapter08Test.java
index 29fd09dc..bb3bd674 100644
--- a/chapter17/src/test/java/com/seaofnodes/simple/Chapter08Test.java
+++ b/chapter17/src/test/java/com/seaofnodes/simple/Chapter08Test.java
@@ -138,7 +138,7 @@ return arg;
 
     @Test
     public void testRegress2() {
-        Parser parser = new Parser("if(1) return 0;  else while(arg>--arg) arg=arg+1; return 0;");
+        Parser parser = new Parser("if(1) return 0;  else while(arg>- -arg) arg=arg+1; return 0;");
         StopNode stop = parser.parse().iterate();
         assertEquals("return 0;", stop.toString());
     }
diff --git a/chapter17/src/test/java/com/seaofnodes/simple/Chapter11Test.java b/chapter17/src/test/java/com/seaofnodes/simple/Chapter11Test.java
index 11424720..ddcc9e63 100644
--- a/chapter17/src/test/java/com/seaofnodes/simple/Chapter11Test.java
+++ b/chapter17/src/test/java/com/seaofnodes/simple/Chapter11Test.java
@@ -292,7 +292,7 @@ else {
 }
 """);
         StopNode stop = parser.parse().iterate();
-        assertEquals("Stop[ return 9; return 0; return 0; ]", stop.toString());
+        assertEquals("Stop[ return 9; return 0; return 0; return 0; return 0; return 0; return 0; return 0; ]", stop.toString());
     }
 
 
diff --git a/chapter17/src/test/java/com/seaofnodes/simple/Chapter17Test.java b/chapter17/src/test/java/com/seaofnodes/simple/Chapter17Test.java
index d39cee2d..3773f87f 100644
--- a/chapter17/src/test/java/com/seaofnodes/simple/Chapter17Test.java
+++ b/chapter17/src/test/java/com/seaofnodes/simple/Chapter17Test.java
@@ -3,6 +3,7 @@ package com.seaofnodes.simple;
 import com.seaofnodes.simple.evaluator.Evaluator;
 import com.seaofnodes.simple.node.StopNode;
 import org.junit.Test;
+import org.junit.Ignore;
 import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.fail;
 
@@ -88,6 +89,17 @@ return s.x;
     }
 
     @Test
+    public void testInc6() {
+        Parser parser = new Parser("""
+return --arg;
+""");
+        StopNode stop = parser.parse().iterate();
+        assertEquals("return (arg+-1);", stop.toString());
+        assertEquals(-1L, Evaluator.evaluate(stop, 0));
+    }
+
+
+    @Test
     public void testVar0() {
         Parser parser = new Parser("""
 var d;