Re: [Chicken-users] Protect against mutation

[Christian Kellermann]

* Bahman Movaqar <address@hidden> [141228 13:00]:
> On 12/27/2014 05:30 PM, Christian Kellermann wrote:
> > * Bahman Movaqar <address@hidden> [141227 13:51]:
> >> Consider the following snippet:
> >>
> >>  (use srfi-1)
> >>  (define (mutator lis n) (set! (first lis) n) lis)
> >>  (define ll (list 1 2 3 4))
> >>  (mutator (cdr lis) 100)
> >>  (equal? (second? lis) 100) --> #t
> >>
> >> Is there anyway to protect "lis" from mutation? TIA,
> > No, you would need immutable list objects, which an egg provides
> > IIRC.
> >
> 
> Thanks for the hint --I was hoping this to be the default behaviour.
> I guess, for me,  setting a personal ban on "set!" is easier than using
> a new vocabulary.

Depending on your use case you should consider an immutable environment
when calling eval?

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