module Netplex_encap

This is a pragmatic approach to type-safe marshalling. We define type encap as an arbitrary value that carries a type identifier with it. The type identifier is generated when the functor Netplex_encap.Make_encap is applied. Every instantiation of this functor generates a new type identifier.

The idea is then that an encap value can be marshalled to another process using Marshal, and when it is unwrapped the type identifier is checked. Unwrapping is only successful when the unwrap function from the same functor instantiation is used as the wrap function.

This module is incompatible with:

• Marshalling to processes running a different executable
• Marshalling to processes that are dynamically loading modules
• The functor must be instantiated at program initialization time. Especially this must not happen in let module expressions.

Only some of these assumptions can be checked at runtime by this implementation.