Mastodawn

As part of my history project, I was looking for a document I wrote that offered specific advice on converting Maclisp and Zetalisp to Common Lisp.

I had to laugh when I found it. It's already published as part of the Sunday Morning Edition of the Pitmanual (the webbed version of the Revised Maclisp Manual, the printed version of which was the Saturday Evening Edition).

The printed version does not contain the conversion guide. It was an "extra" I through in as part of the webbing. But it's perhaps hard to find, so I thought I'd say it out loud. It's several pages that begin here:

https://maclisp.info/pitmanual/cl-conv-01-intr.html

#Lisp #Maclisp #Zetalisp #CommonLisp #KentsHistoryProject #Lisp #ComputerHistory

cc @screwlisp @larsbrinkhoff @eswenson

Kent Pitman Apr 30

I couldn't find a copy of the memo named "Loop Iteration Macro" by Glenn Burke and David Moon, January 1981 (MIT/LCS/TM-169) at MIT's dSpace site, or anywhere else. So I scanned in my copy and have uploaded it to my web site.

NOTE WELL: This document was written prior to CLTL and describes a facility that was available in MACLISP and the Lisp Machine's Zetalisp. Common Lisp drew design ideas from this, but the syntax, semantics, and associated functions/macros described in this are NOT the same as what Common Lisp offers.

For example, my recollection from long ago (which I did not re-check before making this post) is that there are other differences in syntax because this earlier version of Loop was underconstrained in the ordering of the keywords in a way that let you write some expressions that the committee felt might confuse people with their results.

But also, for reasons that slip my mind, Common Lisp did not adopt the define-loop-path macro that is described starting on page 19.

http://nhplace.com/kent/History/maclisp/MIT-LCS-TM-169-Loop-Iteration-Macro.pdf

#lisp #maclisp #loop #iteration #ComputerHistory #KentsHistoryProject #lisp #LispM #Zetalisp #CommonLisp

cc @screwlisp

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Vassil Nikolov | Васил Николов Apr 21

P.S.

Nice fractal!

The index is a good read:
...
circular-link 60
...
no-file-system 56
...
singular-matrix 48
...

#Conditions
#ConditionSystem
#ErrorDetection
#ErrorSignalling
#Lisp
#ZetaLisp

@kentpitman @screwlisp

Kent Pitman Apr 19

@screwlisp

You can pick up the document 'Signalling and Handling Conditions' from this index page:

http://nhplace.com/kent/ZL/

It was longer than I thought it would be, but I think you'll find it interesting to see what the Zetalisp condition system (which inspired the Common Lisp condition system) looked like.

In spirit, it was much the same. The biggest differences are:

* The CL system has 'active' restarts, where the ZL system had a passive thing where you returned a value to the case context and hoped that it would do the thing you wanted. It felt quite a bit more error-prone (if you'll pardon the reuse of 'error' here, maybe I should say 'mistake-prone').

* The ZL condition system offers a lot of really low-level stuff that did not seem proper for CL.

* The set of operations offered in ZL was richer, but also a lot more complicated, I thought, and I worried people would not really see what it was trying to do.

* Obviously, the ZL system was based on Flavors, not CLOS, and made reference to a lot of LispM-specific packages.

* The document was published in January, 1983 and identifies itself as part of Symbolics Release 4.0.

There are other differences as well.

#Zetalisp #LispMachine #LispMachines #Symbolics #LispM
#ConditionHandling #ConditionSystem #ErrorSystem #ErrorHandling #CommonLisp #CL #Flavors #CLOS #History #ComputerHistory
#InternetArchive #Bitsavers