The Algol 60 Programming Language
Table of Contents
1 Why Algol 60?
Programming language researchers have a soft spot for Algol 60. When you first take a look at Algol 60, it will probably not impress you. It's an old, obsolete programming language, with no facility for defining user-defined types, no standard IO library, a very weak static type system, and numerous other limitations. It has no mechanism for allocating memory at run-time; Not even equivalent of the malloc function in C… In many ways, it's more limiting than COBOL (another dead language). And yet,
1.1 Call-by-Name
1.2 Why program in Algol 60 today?
The answer is simple: Algol 60 is the only [once] generally-known programming language available today that will let you experience what it is like to program with the call-by-name parameter-passing mechanism.
Lapidem quem reprobaverunt ædificantes hic factus est in caput anguli
2 Algol 60 compilers
2.1 GNU Marst
Marst is a full implementation of Algol 60. The language is implemented as an Algol-to-C compiler, and the resulting code is then compiled using gcc, linking both to an Algol library as well as the C math library. Compiling to C is a great choice in this case, because it means that Marst is effortlessly portable to many operating systems. I automate the compilation of algol code by using GNU Make, and teaching it the following rule:
.SUFFIXES: .a60
%: %.a60
marst $*.a60 -o $*.c
gcc $*.c -lalgol -lm -o $*
The standard suffix for Algol 60 source files seems to be .alg, but since I tinker, on occasion with Algol 68, which is quite different from Algol 60, I prefer to use .a60 to distinguish source files in the two languages. If you prefer the .alg suffix, then simply change the .a60 strings in the above makefile to .alg.
2.2 PLT Dr Scheme Racket
Racket is a dialect of LISP that developed from a compiler and IDE for Scheme that went by the name of Dr Scheme. Racket comes with what its authors call “experimental languages”, which include an implementation of Algol 60. While Racket seems to be developing rapidly, the Algol implementation appears to lag behind: It is convenient to use, thoughlimited, and suffers from bugs that have not been fixed in years. for these reasons I do not recommend it unless you absolutely cannot use Marst.