Re: Value history

[Neil Jerram]

>>>>> "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?

Regards,
        Neil