Alan Borning did a Sketchpad influenced advance on constraint 
programming in 1977 in Smalltalk-76. This code is around and several 
people have come close to getting it going again in Squeak.

"Hard" is one of those interesting words. Ivan's Sketchpad thesis is 
gettable from MIT in pdf form, and it is quite impressive even by 
today's standards. 40+ years later it should be a nice master's 
thesis for some supergradstudent. But it would be still be a fair 
amount of work from scratch, even though Ivan had to program even the 
line drawing on the TX-2, he had to figure out, design, and build in 
macroassembler on a half MIP machine he could only use about 3 hours 
a day ..... A fabulous Squeak programmer who understands just how 
Sketchpad worked (this is known) could probably replicate the 
original Sketchpad in 1-2 months of work (somebody please prove me 
too pessimistic). OTOH, the "math" and general object model of 
Sketchpad was very (profoundly) simple, so a very clean approach to 
what it was trying to do, coupled with powerful computing so no 
serious optimizations would be required, could be a lot simpler for 
an expert. Doing the iconic UI (the original one) well would still be 
a bit of a challenge....

Cheers,

Alan

------

At 7:21 PM -0400 6/12/03, Brent Vukmer wrote:
>content-class: urn:content-classes:message
>Content-Type: multipart/alternative;
>	boundary="----_=_NextPart_001_01C33139.69604059"
>
>I was wondering -- how hard would it be to re-create Sketchpad in 
>Squeak?  Or maybe my question is really, can Squeak do everything 
>that Sketchpad could do?
>
>Are there functional specs or manual available somewhere that 
>describe in detail what Sketchpad could do?  I've seen grainy photos 
>of Sketchpad, and read some descriptions of it by Alan and others, 
>but that is about all that Google has shown me so far.


-- 
-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://lists.squeakfoundation.org/pipermail/squeak-dev/attachments/20030612/c4e7aa71/attachment.htm