[usocket-devel] Portably supporting :external-format

[Douglas Crosher]

Erik Huelsmann wrote:
>> > So, to stay backward compatible, this is what I'd like to do:
>> >
>> > - If no external-format is given: just return the raw stream returned
>> > by the implementation (as we do now)
>> > - If an external-format is specified, create a raw stream with 'octet'
>> > element-type and wrap the returned stream with a flexi-stream,
>> > exposing the flexi-stream to the caller.
>> >
>> > How about that?
> 
>> Flexi-streams depends on trivial-gray-streams, which appears to
>> support the following implementations:
>>
>>  - Allegro
>>  - CMUCL
>>  - LispWorks
>>  - OpenMCL
>>  - CLISP
>>  - SBCL
>>
>> It doesn't appear to support ABCL or Scieneer CL. For that reason, we
>> can't simply make it a mandatory dependency, unless we want to give up
>> on those implementations. How do you propose we make it optional?

Could you simply add :external-format and :element-type arguments to the
'socket-connection function and allow implementations to return a suitable
stream?  The Scieneer CL has a well designed and fast stream layer capable of
supporting web services with many tens of thousands of connections, and
the function 'ext:make-fd-stream already supports character streams in
Unicode encodings plus a range of handy extensions such a compressed and
encrypted streams.

Flexi-streams is not suitable as a de facto standard - the design is just too
slow to be practical.  If implementations really need to use this then allow
them to do so in the usocket backend.

Regards
Douglas Crosher