Interactive ALGOL 68

Interactive ALGOL 68
Interactive ALGOL 68
Paradigms	structured, imperative
Family	ALGOL
Designed by	Peter Craven
Developer	Algol Applications,; Oxford and Cambridge Compilers Ltd (OCCL)
First appeared	1984; 42 years ago
Final release	Final / 2004; 22 years ago
Typing discipline	static, strong, safe, structural
Scope	lexical
Platform	Intel x86, Inmos Transputer: SPARC
OS	Linux, SunOS-4.1.3 (Solaris 1); Windows 95, NT; OS/2
License	proprietary
Influenced by
	ALGOL 68

The Interactive ALGOL 68 is a structured, imperative high-level computer programming language, a dialect of, and compiler for, ALGOL 68. It was made available by Peter Craven of Algol Applications in 1984,^[1] then in 1994 from OCCL (Oxford and Cambridge Compilers Ltd) until 2004.^[2]

Platforms

Inmos Transputer family
Linux for Intel x86 computers
OS/2 version 2.0 and after
SunOS-4.1.3 (Solaris 1) for SPARC-based computers
Microsoft Windows 95 and Windows NT for Intel

Extensions to standard ALGOL 68

Ability to include source code, and versions of source code.
Nestable comments
FORALL syntactic element for looping over arrays.
ANYMODE a union of all MODEs known to the compiler, and hence dynamic typing.
Enhanced coercions (casting) allowing stringer then "strong" coercions.
Enstructuring automatically coerces a variable from type to struct(type)
Conforming coerces UNION (THING, MOODS) to THING, but if that is not the current mood of the union, then a run-time error will be generated.
Library interface to the native operating system and other libraries.
The operator SIZE
Pseudo-operators ANDTH and OREL, and ANF and ORF for Short-circuit evaluation of Boolean expressions.
Arrays can be slices with stride to select a subset of elements.
MOID is treated differently.

Example of code

MODULE vectors
BEGIN
    INT dim=3;
    MODE VECTOR = [dim]REAL;
    OP + = (VECTOR a, b) VECTOR: ( VECTOR out; FOR i FROM LWB a TO UPB a DO out:=a[i]+b[i] OD; out ),
       - = (VECTOR a, b) VECTOR: ( VECTOR out; FOR i FROM LWB a TO UPB a DO out:=a[i]-b[i] OD; out ),
       DOT = (VECTOR a, b) REAL: ( REAL out:=0; FOR i FROM LWB a TO UPB a DO out+:=a[i]*b[i] OD; out );
END
KEEP VECTOR, +, -, DOT

Restrictions to the language from the standard ALGOL 68

Variable, Modes and Operators must be declared before use.
Anonymous procedure may use rows-declarer as a parameter.
No transient subnames of flexible arrays.
No formatted Transput (or format-texts).
Restricted use of straightening of multiple values during Transput.
Limited use of BYTES, BITS and BOOL.
restricted use of labels to follow EXIT statements.

References

^ "AB52.3.1: Survey of Viable ALGOL 68 Implementations". Archived from the original on 27 September 2007. Retrieved 26 April 2007.
^ "Oxford and Cambridge Compilers Ltd Home Page". Archived from the original on 12 June 2004. Retrieved 26 April 2007.

External links

[1] "AB52.3.1: Survey of Viable ALGOL 68 Implementations". Archived from the original on 27 September 2007. Retrieved 26 April 2007.

[2] "Oxford and Cambridge Compilers Ltd Home Page". Archived from the original on 12 June 2004. Retrieved 26 April 2007.

[1]

[2]