Lambda the Ultimate

The When, Why and Why Not of the BETA Programming Language by Bent Bruun Kristensen, Ole Lehrmann Madsen, and Birger Møller-Pedersen from HOPL-III. BETA was an ambitious follow up to Simula - with orthogonality being a major design goal. The main things I found of interest are the attempts to create a unified abstraction pattern, the emphasis on modeling consistency between design and implementation, and the use of coroutines (ala Simula) for concurrency.

BETA is a programming language that has only one abstraction mechanism, the pattern, covering abstractions like record types, classes with methods, types with operations, methods, and functions. Specialization applies to patterns in general, thus providing a class/subclass mechanism for class patterns, a subtype mechanism for type patterns, and a specialization mechanism for methods and functions.

And while I'm at it, the original entry for HOPL-I on The Development of the SIMULA Languages by Kristen Nygaard and Ole-Johan Dahl is available (starts on page 3). SIMULA is one of a handful of most influential programming languages of all time. I found the following to be amusing:

In the spring of 1967 a new employee at the NCC in a very shocked voice told the switchboard operator: "Two men are fighting violently in front of the blackboard in the upstairs corridor. What shall we do?" The operator came out of her office, listened for a few seconds and then said: "Relax, it's only Dahl and Nygaard discussing SIMULA".

(Link to previous HOPL-III papers on LtU).

For those who like their PL History presented in avante guard beat poetry, a video of Steele & Gabriel's 50 in 50 speech at JAOO is made to order. Or as the link says:

A fun, artistic and enlightning presentation full of interesting facts - and who better to do it than Richard P. Gabriel and Guy L. Steele (the great Quux). Nothing more to say than the rallying cry; More cowbell!

Passing aside the Stephen Wright comic delivery of the two speakers, there are a lot of interesting thoughts, though very few are dwelled on. I think the most interesting things were the languages that they chose as expositions for the major ideas that they covered. Here's the ones that I picked out (though I ended up with only 49):

Do Loops	Fortran (Pascal,APL)	Guarded Commands	Algol-68
Array Origin	C, Fortan, Pascal, APL	Extensible Language	PPL
Domain Specific Language	APT	Structured Programming	BLISS, INTERCAL
Text vs. Environment	Algol-60, Lisp, Smalltalk	Language as Educational Tool	Logo
Stack Machines	Befunge (SECD Machine, Forth)	Formal Dynamic Semantics	SECD
Data Parallelism	APL	Enumerated Types	Pascal
Coercion	PL/I (Fortran-V)	Backtracking and Theorem Proving	Conniver (Prolog)
Hierarchical Records	COBOL	Argument Handling	Common Lisp, Ada, Python (VB, C#, Suneido, PL/pgSQ)
Pointers & Lists	IPL-V	Coding in Natural Language	Perligata (COBOL, Hypercard)
Parsing	Yacc (LR1, Recursive Descent)	Computational Drama	Shakespeare
Linked Records	AED	Reasoning	Prolog
Mathematical Syntax	MADCAP, MIRFAC, Kleerer-May System	Type Declarators	C
Line Numbers	Basic (Focal, APL)	Data Abstraction	CLU, Alphard
Visual Languages	Piet	Dynamic vs. Lexical Scoping	Scheme
Pattern Matching & Replacement	COMIT, SNOBOL	Knowledge Representation	KRL (Conniver, Microplanner)
Branding	Ada (COMIT, SNOBOL, TRAC)	Stream Processing	Lucid
Dynamic Languages	AMBIT/L	Generic Functions	Common Lisp
Program as Data	Lisp	Reflection	3-Lisp
Macro Processor	TRAC, ML/I, Limp, M4	Metacircular Interpreters	Lisp
Call By Name vs. Call By Value	C, Algol-60	Functional Programming	KRC
Dangling Else	Algol-60	Control Parallelism	Occam
Formal Static Semantics	Algol-68	Domain Specific Languages	HQ9+, MUMBLE
Algebraic Formula Manipulation	Formac (Macsyma, Mathematica)	Build Languages	Make, Ant, Rake (JCL)
Message Passing	Smalltalk (C++, C#, Java, Flavors, Common Loops, CLOS, Scheme, Dylan, Simula, Self)	Scripting	Perl
Objects	Simula (Smalltalk, C++, Java)

The 1972 paper by Alan Kay, in commemoration of the 40th anniversary of the Dynabook. (via Coding Horror.)

This note speculates about the emergence of personal, portable
information manipulators and their effects when used by both
children and adults. Although it should be read as science
fiction, current trends in miniaturization and price reduction
almost guarantee that many of the notions discussed will actually
happen in the near future.

Via Patrick (who was once a LtU contributor), two interesting blog posts:

• A discussion of the uses of Lua in Lightroom and about the use of dynamic language to develop desktop software in general (blog post by a LtU member). Apparently, some 63% of the code written by the Adobe Lightroom team is in Lua.
• A brief history of IBM's Visual Age, originally written in Smalltalk (the product, not the blog post), and Digitalk (remember Digitalk?!).

A Simon Peyton Jones interview as part of the series The A-Z of Programming Languages that Naomi Hamilton has been putting together. Posting this one to the front page, not because of any bias towards functional programming, so much as it stands on its own as interesting and insightful from the standpoint of programming language design and evolution.

To supplant established languages, even in the functional programming area, like Haskell or ML or Scheme, you have to build a language that’s not only intriguing and interesting, and enables people to write programs faster, but you also need an implementation that can handle full scale applications and has lots of libraries and can handle profilers and debuggers and graphical analyzers… there’s a whole eco-system that goes with a programming language, and it’s jolly hard work building that up.

Got this in my inbox earlier this week:

Date: Tue, 5 Aug 2008 09:01:12 +0000 (GMT)
From: Jose F. Poveda 
Subject: Re: Problem compiling qsort in mondrian
To: Mondrian Team 
MIME-Version: 1.0

Nigel,
Hi again!! And thanks for your help, it's been
quite useful. I suppose I'm the only person
using Mondrian (hopefully), but the thing is
that I'm implementing quicksort in all languages
of the history. The idea is a historical and
multimedia poster with code incrustated on it,
to include it at the computer science museum of
the city of Malaga. That's why I'm tricking on
mondrian and in many other languages that
probably are useless. And I also worked with F#,
Haskell and as I told you before many many
others.

Regards and thanks again.

Jose F. Poveda
LCC Department
University of Malaga

Scary how time flies. Just eight years ago I joined Microsoft as a young man dreaming of bringing fundamentalist functional programming to the masses. Now I am an old man whose language is inducted to the graveyard of dead programming languages. Apart from this great honor, I believe Mondrian was also briefly mentioned in Guy Steele and Richard Gabriel's fantastic "fifty in fifty" performance, but I was too blown away so I am not sure. Will have to watch the rerun at JAOO extra carefully.

Information on the web about JOVIAL is rather scarce. Came across some old grainy footage of a mpeg video of Jules Schwartz giving an amusing speech for those interested in the early pioneers of PLs.

Things always seem to slow down as we approach this time of year, so I'll post a OOPSLA 2007 video interview of Guy Steele on Programming Languages that I stumbled upon. Covers a range of topics that are of interest to the current and future state of PLs. Nothing too technically deep, but tidbits of interest scattered throughout the interview (especially on DSLs).

(see also prior LtU discussion Guy Steele on Language Design).

(Maybe others have seen this before but I really like the interface that is provided for the video. The list of questions are clickable links which move you to that place in the interview where the question was asked. I hope this catches on for all technical video interviews.)

An ancient paper (July 1978: 30 years ago) from the long gone Lisp Bulletin by Harald Wertz.

The system describes attempts to improve incompletely specified Lisp programs, without however resorting to more information, in the form of specifications, test cases or the like.

A second paper on the system is Stereotyped Program Debugging: an Aid for Novice Programmers.

Mark van Atten (2008). The Development of Intuitionistic Logic. Stanford Encyclopedia of Philosophy.

This article gives an excellent account of the development of intuitionistic logic, from its roots in Brouwer's theological metaphysics, through to its formal presentation by Heyting in 1956. The account is strong on the tensions between the subjectivist motif and the urge to formalise. Via Richard Zach.