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Re: [Chicken-users] basic Scheme question
From: |
Peter Bex |
Subject: |
Re: [Chicken-users] basic Scheme question |
Date: |
Fri, 24 Oct 2008 08:44:06 +0200 |
User-agent: |
Mutt/1.4.2.3i |
On Thu, Oct 23, 2008 at 10:27:18PM -0700, Shawn Rutledge wrote:
> #;10> (begin (define update #f) (let ([v 'foo]) (set! update (lambda
> (d s) (printf "~s was ~s~%" d (eval d)) (set! d s)))))
> #;11> (update 'v 'bar)
> Error: unbound variable: v
>
> What I'm trying to do is pass the name of a let-bound variable in to a
> lambda defined within the let context, in order to tell that lambda to
> access that let-bound variable. eval doesn't work because it looks in
> the outer environment, right? (in which v is not bound)
Eval only sees the top-level environment. It may be possible to use
the environments egg to construct your own environment containing v.
Cheers,
Peter
--
http://sjamaan.ath.cx
--
"The process of preparing programs for a digital computer
is especially attractive, not only because it can be economically
and scientifically rewarding, but also because it can be an aesthetic
experience much like composing poetry or music."
-- Donald Knuth
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- [Chicken-users] basic Scheme question, Shawn Rutledge, 2008/10/24
- Re: [Chicken-users] basic Scheme question,
Peter Bex <=
- Re: [Chicken-users] basic Scheme question, Shawn Rutledge, 2008/10/24
- Re: [Chicken-users] basic Scheme question, Drake Wilson, 2008/10/24
- Re: [Chicken-users] basic Scheme question, Shawn Rutledge, 2008/10/24
- Re: [Chicken-users] basic Scheme question, Drake Wilson, 2008/10/24
- Re: [Chicken-users] basic Scheme question, Shawn Rutledge, 2008/10/24
- Re: [Chicken-users] basic Scheme question, Drake Wilson, 2008/10/24
- Re: [Chicken-users] basic Scheme question, John Cowan, 2008/10/24
- Re: [Chicken-users] basic Scheme question, Shawn Rutledge, 2008/10/26
- Re: [Chicken-users] basic Scheme question, John Cowan, 2008/10/24
- Re: [Chicken-users] basic Scheme question, Elf, 2008/10/28