[racket] TR and ports (in two senses)

Okay. Thanks! --jmj

On May 18, 2014, at 1:52 PM, Asumu Takikawa wrote:

> On 2014-05-16 10:04:17 -0700, Jordan Johnson wrote:
>>   As part of familiarizing myself with Typed Racket I thought I'd port one
>>   or two of the untyped Racket libraries to TR. This raised a few questions:
>>   1) Looking at the TR docs and GitHub repo, AFAICT new library ports go
>>   in pkgs/typed-racket-pkgs/typed-racket-more/typed -- is that right?
> 
> Yes, that's right. Though in the long term with packages, I wonder if we
> should have separate packages for the typed versions of libraries.
> 
>>   2) I don't see documentation or tests for other ported libraries in
>>   general, presumably because they're just wrappers; so, does it suffice to
>>   submit only one file -- the library itself -- or are there more files I'm
>>   not noticing, that go with each library? (Seems I should be documenting
>>   the types I define, but I don't see where those docs would go.)
> 
> You're right, we don't currently have docs or tests in place for those
> wrappers. If you'd like to add some tests, it would probably make sense
> to put them under `typed/<library>/tests` or `typed/tests/<library>`
> perhaps.
> 
>>   3) One of the libs I looked at porting, openssl, raised a question about
>>   subtyping: SSL ports. It appears to me that internally these are standard
>>   Racket input/output ports tagged as special by the openssl library. It
>>   seems straightforward enough to create an opaque type like
>> 
>>     (require/opaque-type SSL-Port ssl-port? openssl)
>> 
>>   but that doesn't capture the idea that every ssl-port should also be of
>>   type Input-Port or Output-Port (as defined in TR already). First, is that
>>   idea correct? And if so, what piece am I missing, to make that happen?
> 
> Unfortunately, there isn't currently a good way to specify that a
> datatype implements an "interface" like being a port, a synchronizable
> event, etc. in Typed Racket.
> 
> For this case, it probably makes sense to just use the built-in Port
> types, which makes the types less precise but it'll work. So you'd give
> `ssl-abandon-port` a type like `(-> Port Void)`. Similarly, the
> `tcp-abandon-port` function has that same type even though it's supposed
> to only take tcp-ports.
> 
> Cheers,
> Asumu