[adrian_b]

But Pascal's variant records (1970-11) had very ugly design errors in comparison with the unions of Algol 68 (1968-12), which made them either useless or annoying for most applicatons.

Niklaus Wirth is well known as a critic of Algol 68 (before the design of Algol 68 was finalized), but in the case of his variant records he has completely failed to create something competitive.

[mzs]

Doesn't look too bad particually the match tagged version last:

  MyType= (Scalar4, Real4, NullTerminatedStringC);
  
  MyUntaggedRecType=
      RECORD
      CASE MyType OF
      Scalar4: (longC:  ARRAY[1..150] OF longint);
      Real4:   (floatC: ARRAY[1..150] OF real);
      END;
  
  MyTaggedRecType=
      RECORD
      CASE tag: MyType OF
      Scalar4: (longC:  ARRAY[1..150] OF longint);
      Real4:   (floatC: ARRAY[1..150] OF real);
      END;
  
  ...
  
  { set all to 0.0 without running through the MC68881 }
  FOR j := 1 TO 150 DO
      longC[j]:= 0;
  
  ...
  
  CASE tag OF
      Scalar4: percentReal = longC[1];
      floatC:  percentReal = floatC[1]*100;
  ELSE
      percentReal = 0.0/0.0;

edit: don't have a pascal compiler handy, but that's the idea

[pjmlp]

Given where Algol 68 ended up, I would say Wirth was quite right.

[adrian_b]

Algol 68 was a failure mainly due to its inappropriate documentation, not due to the quality of the language.

It included many innovations that appeared again in other programming languages only decades later.

Niklaus Wirth was a good teacher and writer and the success of his languages is due mostly to his books and due to his languages being used for teaching in many universities, not due to their technical qualities.

[pjmlp]

I beg to differ, after Modula-2 and Object Pascal (Apple designed it with Wirth's feedback).

Most of his languages ended up losing, because they weren't being shipped with a free beer OS, coupled with a free beer compiler.

[cryptonector]

Algol 68 may have been a failure because it was ahead of its time, which meant it was hard to write a compiler for it. For example, Algol 68 had closures (apparently Knuth snuck them in).

[peoplefromibiza]

> not due to their technical qualities

AFAIK Pascal is C and Algol 68 is C++

people used Pascal because the compiler was blazing fast, it was easier to implement and learn and the features it lacked against Algol did not really matter most of the time (at the time)

More features doesn't automatically means "better"

Also Pascal had quite strong technical qualities, not very common among other contemporary languages

edit: can I ask the reason for the downvote? I would really like to hear an opinion on what Pascal did wrong, having used it extensively in the late 80s until the end of the 90s and why my comment was awarded with a negative score.

[adrian_b]

Extended variants of Pascal, like Turbo Pascal, should not be confused with the Pascal language as designed by Niklaus Wirth.

Wirth's Pascal was a language designed for the purpose of teaching programming and it was adequate for that, but it was completely inappropriate for any serious work.

It had no means for writing big programs that must be divided into multiple source files and it had a lot of design errors, like including the size of an array in its data type (which made impossible the writing of any linear algebra library) or the way of handling the variant records (which was insecure and verbose).

The well known paper "Why Pascal Is Not My Favorite Programming Language" by Brian W. Kernighan contains valid arguments against Pascal (against Wirth's Pascal, there have been many extended Pascals, especially following Turbo Pascal, which have corrected some of the most egregious defects of the original Pascal).

[pjmlp]

People keep playing this tired song, while clearly ignoring that until ISO C89, even C was full of dialects, a mix of K&R C and whatever the compiler writer felt like, filled with tons of Assembly.

Small-C, RatC,....

Additionally forgetting that Modula-2 came out in 1978, as means the sort out all those issues, a language designed for systems programming, instead of the "Python" from 1970, designed for teaching.

With features that C is yet to have, 50 years later, while HN is hypping for having them in a C like syntax delivered in a Zig package.

[peoplefromibiza]

I know that paper and personally I think some of the critiques are actually qualities of pascal, making it, while certainly not a completely refined language, a more modern language than C

- no escape (AKA no casting): good!

- no default clause in case: good idea, not so good implementation (undefined behaviour)

- no break outside for loops: inconvenient, but that's how FP works. it is still debated today if breaking loops is considered a good or a bad practice

- no separated compilation: I will quote Kernighan on this Theoretically, there is no need for separate compilation - if one's compiler is very fast Pascal compiler was fast, maybe not very fast, but speed was one of the primary goals for Wirth.

many other issues were similar in other languages and in C

Pascal had obviously its faults, but every language back then had some

Pascal was simple enough to make it easy to compile and implement. That's what Wirth thaught, he's the author of Compiler Construction after all, it wasn't like learning Python today as a data scientist

make the language more complex (and more useful/interesting) and you're stuck with a very slow or very buggy compiler that very few people would know how to implement

I think there's a reason why we had Turbo Pascal and not Turbo Algol 68