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Pascal origin, where does it come from
Blade:
Interestingly, I found a pdf that introduces Clascal, which later was renamed Object Pascal. Clascal being a play on words of Pascal, as in Pascal with Classes. This talks about the concept of Clascal, what inspired it, and differences between it and versions of Pascal at that time. Also included is a download of the Lisa Pascal manual, as it's referenced in the Clascal document and the extensions were built on top of it.
Download PDF- An Introduction To Clascal
Download PDF- Lisa Pascal Reference Manual
--- Quote from: MarkMLl on August 08, 2020, 09:49:28 am ---Another thing that tends not to be discussed is that Wirth acted as a (AIUI paid) consultant to the Ada design process. It's interesting that later on he appeared to be very hostile to OO, arguing that everything could be done adequately using records.
--- End quote ---
Yes, information about Pascal's and Wirth's connection to Ada is hard to come by too, though in looking at Ada, it becomes readily apparent. Even Wiki makes no mention of Wirth's influence on Ada, though gives a brief mention of Pascal.
As for OOP, there is a famous quote attributed to Wirth, "Nevertheless, I consider OOP as an aspect of programming in the large; that is, as an aspect that logically follows programming in the small and requires sound knowledge of procedural programming."
I can see where Wirth is coming from, because Pascal has records, nested functions, variants, and units. OOP is very much a choice, as oppose to a necessity or forced paradigm like it is in various other languages. From that perspective, OOP is used when appropriate or where it makes sense versus "if all you have is a hammer, everything looks like a nail". Wirth may have seen through the hype early, and knew OOP was not necessarily the "be all, end all". There is composition versus inheritance, modularization in contrast to OOP's take on encapsulation, and polymorphism is not owned by only OOP.
MarkMLl:
--- Quote from: Blade on August 08, 2020, 11:13:50 am ---Yes, information about Pascal's and Wirth's connection to Ada is hard to come by too, though in looking at Ada, it becomes readily apparent. Even Wiki makes no mention of Wirth's influence on Ada, though gives a brief mention of Pascal.
--- End quote ---
But equally, Ada could have been "Child of ALGOL-68" since it has a terminating END on conditionals etc., which is in neither Pascal nor ALGOL-W.
I'm afraid that I've not been through all of OP's references, but an interesting question is whether the original Modula (i.e. predating Modula-2) had an explicit terminating END. The "THEN applies to a single statement" structure is undeniably elegant and is delightfully consistent with the in-expression IF-THEN-ELSE supported by ALGOL, but is a PITA in practice.
It's most unfortunate that the Great Unwashed- which includes 95% of programmers- insists on classifying languages as "Pascal-like" or "curly-bracket" solely on the use of BEGIN vs {
MarkMLl
Blade:
"Larry Tesler worked with Niklaus Wirth to add object-oriented language extensions to the Pascal programming language."
It appears that Larry Tesler (who had an amazing career), was the person at Apple that was directing or creating the extensions (first known as Clascal, then Object Pascal) to Apple's Lisa Pascal (with consultation from Niklaus Wirth).
Among the many interesting things about Larry Tesler, he was the person Xerox assigned to show Steve Jobs around Xerox's Palo Alto Research Center in 1979. Computing legend Alan Kay (designer of Smalltalk and inventor of the term OOP) was the one who hired Tesler for Xerox in the first place, and then it was Steve Jobs who hired him away to work at Apple.
winni:
Hi!
In the 70s Xerox needed urgent new ideas. They started the Xerox Palo Alto Research Center (PARC) where crazy genious persons should develop new ideas and concepts. Often enough that were Acid dropouts - dont underestimate the influence of LSD in those days. Those persons were not able for daily work but they had great ideas: They invented the Mouse, they invented the GUI, they invented PostScript and they invented the Laser Printer. And they invented the Ethernet.
Where were we now without them??
Winni
Blade:
As we are going down memory lane and doing origins. The Lisa Pascal Reference Manual, for which Clascal (later Object Pascal) is based on, is itself based on and references the Pascal User Manual and Report (the basis of the ISO standard), created by Kathleen Jensen and Niklaus Wirth. Presented as viewable PDF.
Pascal User Manual and Report
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