This module generates Haskell code for serialising and deserialising libevent tagged data structures, as implemented in libevent-1.4.0-beta.

A single .rpc file (containing one or more structures) is mapped to a single Haskell file. Take this example:

 struct test {
   required int a = 1;
   optional string b = 2;
   repeated struct[test2] c = 3;
 }

This will result in a data decl for Test, having named members: test_a, test_b and test_c. Required elements are simple, optional elements are wrapped in a Maybe and repeated elements in a list.

Types are mapped thus:

• int -> Word32
• string -> String
• bytes -> ByteString (strict)
• bytes[n] -> ByteString (with runtime checks on the size)
• struct[name] -> Name (the struct must be defined in the same file)

In the example above, test2 is required to be in the same .rpc file.

For a structure named test, the following would also be generated:

• testEmpty - a Test filled with default values
• testDeserialise - a strict Get instance to deserialise a test. Note that these structures are self-deliminating, so additional garbage at the end will be consumed and will probably result in an error
• testDeserialiseBS - a function with type ByteString -> Either String Test where the String is an error message
• testSerialise - a Put Test function. Again, recall that these structures aren't self deliminating
• testSerialiseBS - a function with type Test -> ByteString

Each structure will also be an instance of the TaggedStructure class that you can find in Codec.Libevent.Class