adding comments

tls/Network/TLS/Extension.hs-boot

@@ -1,3 +1,15 @@
+-- This is a breaker for cyclic imports:
+--
+-- - Network.TLS.Extension imports Network.TLS.Struct
+-- - Network.TLS.Extension imports Network.TLS.Packet
+--
+-- - Network.TLS.Struct imports Network.TLS.Extension
+--
+-- - Network.TLS.Packet imports Network.TLS.Struct
+--
+-- Originally, ExtensionRaw was defined in Network.TLS.Struct and no
+-- cyclic imports exist. It is moved into Network.TLS.Extension for
+-- pretty-printing, so the cyclic imports happen.
 module Network.TLS.Extension where
 
 import Data.ByteString

tls/Network/TLS/Types/Cipher.hs

@@ -28,6 +28,10 @@ instance Show CipherID where
         eqID c = cipherID c == CipherID n
         dict = unsafePerformIO $ readIORef globalCipherDict
 
+-- "ciphersuite" is designed extensible.
+-- So, it's not available from internal modules.
+-- This is a compromise to gule "ciphersuite" to Show CipherID.
+
 {-# NOINLINE globalCipherDict #-}
 globalCipherDict :: IORef [Cipher]
 globalCipherDict = unsafePerformIO $ newIORef []