[slime-devel] Re: memory leak caused by clickable value history in the SLIME REPL

[Matthias Koeppe]

Marco Baringer <mb at bese.it> writes:

> "Hoehle, Joerg-Cyril" <Joerg-Cyril.Hoehle at t-systems.com> writes:
>
>> In my particular case, huge data structures would have been ready
>> to free if SLIME had not kept that link.  How can I clear this
>> value cache, or control the cache policy?
>
> you can disable it completly by setting swank::*record-repl-results*
> to nil. you can clear the current set of values by clearing the repl
> buffer (M-x slime-repl-clear-buffer or C-c C-t).

I would like to add that the history is meant to be implemented by a
_weak_ hash table, using the SLIME backend functions
MAKE-WEAK-KEY-HASH-TABLE and MAKE-WEAK-VALUE-HASH-TABLE.  If those are
implemented properly for a CL implementation that supports weak
hashtables, the REPL history items (and other presentations) do not
cause any memory leak.

The functions are implemented both for Allegro CL and SBCL, but not
for CLISP (which Jörg might be using), which I think has excellent
support for weak hash tables.

-- 
Matthias Köppe -- http://www.math.uni-magdeburg.de/~mkoeppe