[Types-sig] Interface files

[Paul Prescod]

skaller wrote:
> 
> In other words, interface files should be regarded as an _artefact_
> of the existing 'lack of syntax for defining a module'.
> [Which Viper may correct :-]

If the normative spec. is in terms of interface files then we can deal
with various situations through transformation TO interface files:

 * C modules
 * "read-only" Python modules (like library modules that you don't want
to change)
 * modules (in any language) already defined by IDL
 * Python modules with embedded declarations
 * Python modules without embedded declarations that "use"
non-conservative type inferencing

 Paul Prescod