Skip lone ident statments or for-loop assignments

SL's LSL supports lone idents:

    integer x;
    x;

as well as lone idents in for-loop assignments:

    for (x; x < 10; x++) { ... }

while those are errors in C# (MONO at least). This patch skips lone
idents in such places.

Fixes Mantis #3042.

OpenSim/Region/ScriptEngine/Shared/CodeTools/CSCodeGenerator.cs

@@ -90,7 +90,7 @@ namespace OpenSim.Region.ScriptEngine.Shared.CodeTools
             m_warnings.Clear();
             ResetCounters();
             Parser p = new LSLSyntax(new yyLSLSyntax(), new ErrorHandler(true));
-            // Obviously this needs to be in a try/except block.
+
             LSL2CSCodeTransformer codeTransformer;
             try
             {
@@ -446,8 +446,11 @@ namespace OpenSim.Region.ScriptEngine.Shared.CodeTools
                 // Jump label prints its own colon, we don't need a semicolon.
                 printSemicolon = !(s.kids.Top is JumpLabel);
 
-                foreach (SYMBOL kid in s.kids)
+                // If we encounter a lone Ident, we skip it, since that's a C#
-                    retstr += GenerateNode(kid);
+                // (MONO) error.
+                if (!(s.kids.Top is IdentExpression && 1 == s.kids.Count))
+                    foreach (SYMBOL kid in s.kids)
+                        retstr += GenerateNode(kid);
             }
 
             if (printSemicolon)
@@ -711,6 +714,14 @@ namespace OpenSim.Region.ScriptEngine.Shared.CodeTools
 
             int comma = fls.kids.Count - 1;  // tells us whether to print a comma
 
+            // It's possible that all we have is an empty Ident, for example:
+            //
+            //     for (x; x < 10; x++) { ... }
+            //
+            // Which is illegal in C# (MONO). We'll skip it.
+            if (fls.kids.Top is IdentExpression && 1 == fls.kids.Count)
+                return retstr;
+
             foreach (SYMBOL s in fls.kids)
             {
                 retstr += GenerateNode(s);

OpenSim/Region/ScriptEngine/Shared/CodeTools/Tests/CSCodeGeneratorTest.cs

@@ -132,6 +132,32 @@ state another_state
             Assert.AreEqual(expected, output);
         }
 
+        [Test]
+        public void TestLoneIdent()
+        {
+			// A lone ident should be removed completely as it's an error in C#
+			// (MONO at least).
+            string input = @"default
+{
+    touch_start(integer num_detected)
+    {
+        integer x;
+        x;
+    }
+}
+";
+            string expected =
+                "\n        public void default_event_touch_start(LSL_Types.LSLInteger num_detected)" +
+                "\n        {" +
+                "\n            LSL_Types.LSLInteger x = new LSL_Types.LSLInteger(0);" +
+				"\n            ;" +
+                "\n        }\n";
+
+            CSCodeGenerator cg = new CSCodeGenerator();
+            string output = cg.Convert(input);
+            Assert.AreEqual(expected, output);
+        }
+
         [Test]
         public void TestAssignments()
         {
@@ -1540,6 +1566,31 @@ default
             Assert.AreEqual(expected, output);
         }
 
+        [Test]
+        public void TestForLoopWithOnlyIdentInAssignment()
+        {
+            string input = @"default
+{
+    state_entry()
+    {
+        integer x = 4;
+        for (x; 1<0; x += 2);
+    }
+}";
+
+            string expected =
+                "\n        public void default_event_state_entry()" +
+                "\n        {" +
+                "\n            LSL_Types.LSLInteger x = new LSL_Types.LSLInteger(4);" +
+                "\n            for (; new LSL_Types.LSLInteger(1) < new LSL_Types.LSLInteger(0); x += new LSL_Types.LSLInteger(2))" +
+                "\n                ;" +
+                "\n        }\n";
+
+            CSCodeGenerator cg = new CSCodeGenerator();
+            string output = cg.Convert(input);
+            Assert.AreEqual(expected, output);
+        }
+
         [Test]
         public void TestAssignmentInIfWhileDoWhile()
         {