Re: [Chicken-users] Bug with #!optional in Chicken 4.8.0

[Felix]

From: John Croisant <address@hidden>
Subject: [Chicken-users] Bug with #!optional in Chicken 4.8.0
Date: Sat, 13 Oct 2012 20:34:26 -0400

> In Chicken 4.8.0, procedures defined with #!optional no longer signal
> an exception if invoked with too many arguments. For example:
> 
> (define (foo x #!optional y) (list x y))
> (foo 'x 'y 'too 'many 'args)
> 
> In Chicken 4.7, this would signal an exception, because the foo
> procedure expects a maximum of 2 arguments. In Chicken 4.8, the extra
> arguments are simply ignored.
> 
> I think this is a bug, because the docs for "Extended DSSSL style
> lambda lists" say:
> 
>> If there is no rest-parameter  and no keyword-parameters in the
>> parameter-list, then it shall be an error for any extra arguments to
>> be passed to the procedure.

That is correct. The check has been removed and conflicts with
the documentation. I will update the docs accordingly. 

The check has been removed to accomodate a terrible hack for handling
re-initialization of parameters with "parameterize", and for a slight
performance win. The hack is so terrible, I hardly dare to talk about
it in public. On the other hand, I see no problem in allowing extra
parameters to lambdas with rest/optional arguments being silently
dropped - it has been done before.


cheers,
felix