Hugh Perkins wrote:
Now, arguably the fact that we are pattern matching on the receiver at least means we dont do anything with the invalid data sent, but this is not rocket science: the standard technique to ensure decent compile time validation in rpc-type things is to use an interface.
The interface defines the method names and parameters that you can send across. Both the receiver and the sender have access to the interface definition, and it is trivial to check it at compile time.
(Caveat: havent looked enough into Erlang to know if there is a good reason for not using an interface?)
Remember that Erlang is an untyped language and that you are allowed to send any kind of data. However, there is more to consider here: A certain amount of dynamism wrt the message content (high level protocol) is necessary for systems for which Erlang was designed, namely large distributed control systems with minimum down-times. For large distributed installations it is a matter of practicality to be able to upgrade one component w/o needing to recompile (and then re-start) all the other components that it communicates with -- for systems with expected down-times of 3 Minutes per year it is a matter of being able to meet the specifications. You'll have a hard time finding high-availability or large control systems which use an IDL approach for communication. Cheers Ben