LAmbda calculus evaluator (interactive)

[David C. Ullrich]

On Sun, 23 Apr 2000 00:48:08 -0400, "Tim Peters"
<tim_one at email.msn.com> wrote:

>[Kragen Sitaker]
>> ...
>> Many years ago, Colby Kraybill suggested to me that it would be nice
>> to have something similar for mathematical expressions --- something
>> that would do nothing on its own, but would do the grunt-work involved
>> in an action like "take the reciprocal of both sides" or "divide both
>> the top and bottom by (x-1)".
>
>Hyland Software's "Merlyn" program does that; see
>
>    http://www.hylandsoftware.com/
>
>It's based on a general term-rewriting system, and is programmable by the
>end-user (indeed, almost all the builtin rules are exposed in files you can
>edit too).  However, it's proprietary, costs money, source for the engine
>itself is not available, and it works only on Windows.  I often use it
>instead of, e.g., Macsyma, because the high-powered systems drive me nuts
>with the pervasive & often unhelpful transformations they make in an
>eyeblink; Merlyn never does anything unless it's told to.
>
>Similar but weaker symbolic facilities can be found, e.g., in Dave
>Gillespie's Emacs calc, and high-end HP calculators.
>
>If the world were sane, they would have written all these things in Python
><wink>.

	So if they'd written them in Python what would the source
code look like? 

>the-temptation-to-use-the-time-machine-is-often-overwhelming-ly y'rs  - tim

	So you have a time machine - so "too busy" is no excuse...

DU