Compiler
The Interactive ALGOL 68 compiler for ALGOL 68 was made available by Peter Craven of Algol Applications from 1984.[1] Then in 1994 from OCCL (Oxford and Cambridge Compilers Ltd) until 2004.[2]
Extensions to standard ALGOL 68
[edit]- 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.
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
[edit]- 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.
