[Mono-bugs] [Bug 35169][Min] New - #else in tokenizer

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Changed by f_azi@hotmail.com.

http://bugzilla.ximian.com/show_bug.cgi?id=35169

--- shadow/35169	Thu Dec  5 16:43:50 2002
+++ shadow/35169.tmp.30028	Thu Dec  5 16:43:50 2002
@@ -0,0 +1,89 @@
+Bug#: 35169
+Product: Mono/MCS
+Version: unspecified
+OS: 
+OS Details: 
+Status: NEW   
+Resolution: 
+Severity: 
+Priority: Minor
+Component: Misc
+AssignedTo: mono-bugs@ximian.com                            
+ReportedBy: f_azi@hotmail.com               
+QAContact: mono-bugs@ximian.com
+TargetMilestone: ---
+URL: 
+Cc: 
+Summary: #else in tokenizer
+
+Please fill in this template when reporting a bug, unless you know what 
+you are doing.
+Description of Problem:
+Using hte snapshot of Dec 04/02.
+Problems parsing code with stacked #if, #else, #endif directives.
+
+
+Steps to reproduce the problem:
+The following code will reproduce the problem:
+#if FLAG_FALSE
+	namespace ns1
+#else
+	#if FLAG_FALSE
+			#if FLAG_FALSE
+				namespace ns2
+			#else
+				namespace ns3
+			#endif
+	#else
+		#if FLAG_TRUE
+			namespace ns4
+		#else
+			namespace ns5
+		#endif
+	#endif
+#endif
+{
+	public class TheClass
+	{
+		public TheClass() 
+		{
+		}
+	}
+} 
+
+The problem is on the procesing of the #else. In the current code the 
+status on the stack is not updated when processing the 'else' so 
+the 'if''s status is keept in the stack. Then the son's of the else have 
+the wrong parent information on the stack.
+One way of solving the issue is as follow:
+
+case "else":
+    if (ifstack == null || ifstack.Count == 0){
+        Report.Error (1028, Location,"Unexpected processor directive (no 
+#if for this #else)");
+        return true;
+    } else {
+        int state = (int) ifstack.Peek ();
+
+        if ((state & ELSE_SEEN) != 0){
+            Error_UnexpectedDirective ("#else within #else");
+            return true;
+	}
+
+	ifstack.Pop ();
+
+	bool bRet;
+	if ((state & TAKEN_BEFORE) == 0){
+	    bRet = ((state & PARENT_TAKING) != 0);
+	} else
+	    bRet = false;
+
+	if (bRet)
+	    state |= TAKING;
+	else
+	    state &= ~TAKING;
+
+	ifstack.Push (state | ELSE_SEEN);
+
+	return bRet;
+    }