Re: srfi-9 record type checking

[Neil Jerram]

address@hidden (Ludovic Courtès) writes:

> Kevin Ryde <address@hidden> writes:
>
>> I guess `define-record-type' should be making a stricter procedure
>> than `record-accessor' gives.
>>
>> I got bitten by this using `record-accessor' the other day.  For some
>> reason I thought it had strict type checking and scratched my head for
>> a while until realizing I was passing a wrong record and getting back
>> #f.  Is that #f a feature?  Would there be scope to add an option to
>> ask for a strict checking version?  Or make that the default?
>
> I don't think we can add an optional argument to `record-accessor' while
> preserving the current behavior by default.  That optional argument
> would have to be more than just a default value: typically it would have
> to be a wrong-type-arg handling procedure, and this would add too much
> overhead IMO (OTOH, one may argue that we shouldn't worry too much about
> overhead in error conditions).
>
> Instead, we could perhaps add `record-type-strict-accessor'?

I vote for just fixing record-accessor to be strict by default;
i.e. treating current behaviour as a bug.  I'd be surprised if anyone
was relying on this, and if they are it's easy to code a workaround.

Regards,
      Neil