Update

svn path=/trunk/mcs/; revision=65404

diff --git a/mcs/CodingStyle b/mcs/CodingStyle
index 9ca84959917b39c875168e8a4dce2d382cc3bbc0..43d74117a55e2ee774230289e53da143618ff600 100644 (file)
--- a/mcs/CodingStyle
+++ b/mcs/CodingStyle
@@ -464,4 +464,44 @@ class X : Y {
                }
        }
 }
-       
+
+* Conditional compilation
+
+       Ideally we would not need conditional compilation, and the use
+       of #ifdef is strongly discouraged.  But due to our support for
+       old C# 1.0 compilers we have to use it in a few places.
+
+       Try to avoid negative tests that have an else clause, for
+       example:
+
+           #if !NET_2_0
+               CODE_FOR_1_0
+            #else
+               CODE_FOR_2_0
+           #endif
+
+        Instead use:
+
+           #if NET_2_0
+               CODE_FOR_2_0
+           #else
+               CODE_FOR_1_0
+            #endif
+
+       When a major feature differs across compilation targets, try
+       to factor out the code into a separate class, a helper class
+       or a separate file, and include that in your profile while
+       surrounding that helper file/class with the ifdefs to reduce
+       the amount of ifdefs in the code.
+
+       For instance, this is used for some parts of Grasshopper where
+       the code is ifdefed out, when large parts of a file would have
+       been ifdefed out, we moved the code into a MyOtherFile.jvm.cs
+
+       For 2.0 classes, this is even simpler as code can be trivially
+       factored out into 
+
+                MyHelperClass.cli.cs
+                MyHelperClass.jvm.cs
+
+       By using partial classes.
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