Re: Value history

[Dirk Herrmann]

On 2 Mar 2001, Neil Jerram wrote:

> >>>>> "Dirk" == Dirk Herrmann <address@hidden> writes:
> 
>     Dirk> On Thu, 1 Mar 2001, Keisuke Nishida wrote:
>     >> This is a quick hack that enables a value history in the
>     >> current repl.
> 
>     Dirk> Very nice!  Can this be made into a module that the user may
>     Dirk> load on demand?  If so, I would like this to be added!  Btw,
>     Dirk> IIRC there was a similar proposal some time ago that used a
>     Dirk> ring buffer instead of a module.
> 
> That was my implementation.  I think the differences from Keisuke's
> approach are:
> - uses a read hash extension to retrieve a saved value rather than
>   creating new bindings; so can't clash with application variables
>   called `$1' etc
> - the value history has a limited size, so old values are eventually
>   dropped and can be GC'd
> - it works for multiple REPLs running simultaneously (in different
>   dynamic roots)
> - allows the user to choose whether or not to activate value history
> - uses a new hook to hook into boot-9.scm, rather than adding
>   something like `value-history-save' explicitly.
> 
> Should I repost it for comparison?

Yes, please.  I seem to remember that you had planned to extract the ring
buffer code into a module of its own, right?  In general, I like the idea
to use hooks to extend the functionality of the repl, but this could be
easily done with Keisuke's approach as well.

Best regards,
Dirk Herrmann