[slime-devel] ABCL reversion in 2008-12-30 (Re: Compilation output goes to *inferior-lisp* buffer under ABCL

[Mark Evenson]

After some investigation, I still don't understand what is going wrong 
here, but can report that after 2008-12-30, ABCL's SLIME definitely has 
the symptom that all output goes to the *inferior-lisp* buffer as 
opposed to the REPL bugger.  And I should at least report what I have 
been able to determine more exactly about my confusion.

My main (mis)undestanding is that it seems as if the use of the 
WITH-CONNECTION macro is not properly binding *STANDARD-OUTPUT* to the 
output stream stored in the ENV field of the CONNECTION structure.   Nor 
does the binding of the rest of the standard streams *ERROR-OUTPUT*, 
*DEBUG-IO*, *TERMINAL-IO* look correct.  The code in 
CALL-WITH-CONNECTION, used by the WITH-CONNECTION macro reads:

(defun call-with-connection (connection function)
   (if (eq *emacs-connection* connection)
       (funcall function)
       (let ((*emacs-connection* connection)
             (*pending-slime-interrupts* '()))
         (without-slime-interrupts
           (with-swank-error-handler (*emacs-connection*)
             (with-io-redirection (*emacs-connection*)
               (call-with-debugger-hook #'swank-debugger-hook 
function)))))))

meaning that the WITH-IO-REDIRECTION macro will never be invoked if the 
REPL is being used as (eq *emacs-connection* connection)?  This is the 
opposite of what I would expect from my understanding of what 
*emacs-connection* means.

But ECL seems to work with this code which is odd as ECL uses the same 
communication style (NIL) as ABCL, but ECL doesn't exhibit these sort of 
problems.  I don't really undestand the intricacy of the closure that is 
made over the reader function created in the invocation of 
MAKE-REPL-INPUT-STREAM.  The only difference in the code used by SLIME 
between ECL and ABCL is that ABCL doesn't use Gray streams (it doesn't 
really have them) as opposed to ECL, which does, in the 
MAKE-INPUT-STREAM/MAKE-OUTPUT-STREAM definitions.  I can't think of what 
distinction might make, but I note it in case it strikes a chord with 
someone else.

The following function

(defun fix-standard-output (connection)
   (setf *standard-output*
         (cdr (find '*standard-output*
                    (connection.env connection)
                    :test #'equal :key #'car))))

when invoked on the REPL after SLIME starts via

CL-USER> (fix-standard-output swank::*emacs-connection*)

seems to restore the output behavior. Similar functions are probably 
needed for the other standard streams.

When I tried to bind *STANDARD-OUTPUT* to the value stored in 
CONNECTION.ENV at the same place *STANDARD-INPUT* is bound in 
SIMPLE-SERVE-REQUESTS, I get a stack overflow in the running of 
SWANK-LOADER.











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