[trivial-gray-streams-devel] [cl-plus-ssl-devel] trivial-gray-streams becomes a separate project

[Anton Vodonosov]

Hello.

BTW, there is a trivial-gray-streams-devel list...
http://lists.common-lisp.net/cgi-bin/mailman/listinfo/trivial-gray-streams-devel

What I understand:

This code provides Gray streams implementation for MCL and SCL 
(these project do not implement the Gray streams proposal)

So far trivial-gray-streams only provided compatibility layer between 
different Gray streams implementations (all the Lisps supported have 
Gray streams). trivial-gray-streams only re-export the gray stream function
provided by exisging Lisps from trivial-gray-streams package and make 
some fixes/unifications as in case of stream-read-sequence, which is 
absent in Gray streams proposal and therefore sometimes is implemented differently 
in different lisps.

If we commit this code, trivial-gray-streams will get somewhat
different purpose - in addition to be a compatibility layer on top 
of Gray streams, it will also provide the Gray streams for MCL and SCL.

Maybe it's better to commit the Gray streams to MCL and SCL...
But if it's problematic, why not commit it to trivial-gray-streams...
at least there will be no incompatibilities between trivial-gray-stream
and MCL/SCL Gray streams (but we will need to care about
compatibility between MCL/SCL Gray streams and MCL/SCL internals
used in the Gray streams implementation).

Have you tried to suggest the Gray streams implementation to MCL and SCL?

I don't have MCL (and mac to run it), and I can't say I read and understood every line
of the code, but if you say the code works...

Could you explain the issue pointed by Daniel, when the gray stream function calls a
function from CCL package, and the function in the CCL package calls the Gray streams
function? How it is resolved? By inheriting from fundamental-stream and redefining
one of the functions or how?

(defmethod stream-file-position ((stream fundamental-stream))
  (ccl:stream-position stream))

(defmethod (setf stream-file-position) (position (stream fundamental-stream))
  (ccl:stream-position stream position))

(defmethod ccl:stream-position ((stream fundamental-stream) &optional position)
  (if position
    (setf (stream-file-position stream) position)
    (stream-file-position stream)))

Best regards,
- Anton

25.06.2011, 15:58, "Chun Tian (binghe)" <binghe.lisp at gmail.com>:
> A updated version of mcl-gray-streams.lisp which could make chunga work on MCL, it replaces CLOSE and OPEN-STREAM-P into generic functions.
>
> 在 2011-6-25，13:53， Chun Tian (binghe) 写道：
>
>>  Hi, David
>>
>>  I'm not sure, but I think it's possible to change MCL's any behavior by just loading new code into it, to make it looking like having native support of Gray Streams.
>>
>>  And I think the whole purpose is just to make those packages which depends on trivial-gray-streams running well on MCL, and I'll try to analyze any issue in this process and figure out a solution to fix it.
>>
>>  For example, today, when I can try to load Chunga (depend by Hunchentoot) into MCL, I found it try to define a method on OPEN-STREAM-P, which is a standard CL ordinary function but generic function in MCL:
>>
>>  (defmethod open-stream-p ((stream chunked-stream))
>>   "A chunked stream is open if its underlying stream is open."
>>   (open-stream-p (chunked-stream-stream stream)))
>>
>>  To make above code runs on MCL, MCL's own function OPEN-STREAM-P need to be overridden, and this is quite possible and I'm just working on it.
>>
>>  Any way, I hope my initial work being merged first to have a base point, and then people like you and me could have more patches to fix any rest issue in it.
>>
>>  --binghe
>>
>>  在 2011-6-25，00:18， David Lichteblau 写道：
>>>  Quoting Chun Tian (binghe) (binghe.lisp at gmail.com):
>>>>  The MCL support code was written by Terje Norderhaug with my little
>>>>  modifications, it's partly confirmed by my own projects which depend on
>>>>  trivial-gray-streams and running on MCL;  the SCL support code is from IOlib
>>>>  project, untested (because I don't have a valid license), but I believe it
>>>>  should work, at least no harm to other platforms.
>>>  Cool, thanks.  Quick feedback:
>>>
>>>  It looks to me like many definitions are recursive, i.e. the gray
>>>  streams methods call MCL internals, which call gray steams methods.
>>>
>>>  trivial-gray-streams does not attempt to offer user code the ability to
>>>  call low-level STREAM-foo functions.  Rather, it aims to allows stream
>>>  implementors to define STREAM-foo methods such that the CL stream system
>>>  will end up calling that implementation.
>>>
>>>  I.e. the method CCL:STREAM-POSITION seems correct in calling
>>>  STREAM-FILE-POSITION, but the reverse method on STREAM-FILE-POSITION
>>>  that calls CCL:STREAM-POSITION is meaningless and should either say
>>>  (error "not implemented")
>>>  or the method could be left out entirely, leaving it to the Lisp to
>>>  signal the condition that no method is applicable.
>>>
>>>  (If I'm reading the code right.)
>>>
>>>  d.
>>>
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>
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