Re: 23.0.50; savehist save invalid syntax

[Stefan Monnier]

>> I think the best approach is to discard any element of command-history
>> that contains anything unreadable.  If the arguments of a command
>> include a mouse event, repeating it in another session won't make much
>> sense anyway.

> With this much complexity, my temptation would be to provide a
> print-readable function (or an optional argument to an existing printer)
> that signalled if it  were asked to print something that has no read
> syntax.  Of course, this could be done in Lisp by recursively checking the
> type of every element of every sequence, but that would traverse the tree
> twice and would fail on circular structures unless `print-circle' were
> duplicated within it.

Agreed, except that rather than failing, the function should call a callback
which could choose to print those failed elements in some way (or to signal
an error).


        Stefan