cce at ccs.neu.edu
Fri Jun 22 14:11:28 EDT 2007
On 6/22/07, Onnie Winebarger <owinebar at gmail.com> wrote:
> Is this the only way to achieve that goal, or just a convenient one?
> It is an unfortunate decision, in any case. The Scheme that makes
> impurity second-class is not the true Scheme.
In this setup, it's easy to achieve a guarantee of purity (don't
import set-c[ad]r!), and easy to achieve impurity (import them). It's
a one-line difference. In previous Schemes, impurity is the default
but achieving purity requires examining the whole program, and there
was no builtin mechanism to guarantee it. I think the R6RS solution
comes closer to making both kinds of programming first-class.
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