No way to make user defined data types translatable

[flambard]

There should be some clearly defined way of making user defined data types 'Erlang translatable'.

i.e. define the CLERIC:ENCODE method for your new data type and make it transform your object into valid Erlang terms.

When a new data type is Erlang translatable it must also be a subtype of ERLANG-TRANSLATABLE (see type-erlang-translatable.lisp.)