On 12/1/10 10:14 PM, Hendrik Boom wrote:
On Wed, Dec 01, 2010 at 09:09:04PM -0500, David Van Horn wrote:
On 12/1/10 9:03 PM, YC wrote:
Thanks - I have read the substitution part of PLAI and thought of using
substitution as well, but it seems that substitution does not constitute
the full solution:
* it only work with side-effect free code
This is not entirely true, but substitution and effects are subtle.
The actual prblem is that the parameter is reevaluated every time it's
used in teh called function. THis lacke efficiency, but occasionally
(as in Algol 60's call-by-name it's exactly what you need,)
* it does not address closure
You don't need closures in a substitution model.
No, as long as you take care to use systematic renaming of variables.
You luck out and get to avoid this issue if you implement a
call-by-value language.
David
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