► |  | Algol 60

1 | Implementation
2 | Including Algol 60 Programs
3 | Language

Algol 60
1`` Implementation
2`` Including Algol 60 Programs
include-algol
literal-algol
3`` Language

7.2
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## Algol 60

### 1`` Implementation

The “Algol 60” language for DrRacket implements the language defined by the “Revised Report on the Algorithmic Language Algol 60,” edited by Peter Naur.

### 2`` Including Algol 60 Programs

Although Algol 60 is mainly provided as a DrRacket language, include-algol supports limited use of Algol 60 programs in larger programs.

(require algol60/algol60) | package: algol60

> syntax (include-algol path-string)

Includes the Algol 60 program indicated by path-string as an expression in a Racket program. The included Algol 60 program is closed (i.e., it doesn’t see any bindings in the included context), and the result is always #<void>.

> syntax (literal-algol string ...)

Evaluates the Algol 60 program indicated by the literal strings as an expression in a Racket program. The Algol 60 program is closed (i.e., it doesn’t see any bindings in the included context), and the result is always #<void>.

This is generally useful when combined with the at-exp reader, e.g.,

> #lang at-exp racket
> @literal-algol{
> begin
> printsln (`hello world')
> end
> }

### 3`` Language

The DrRacket and include-algol implementation departs from the Algol 60 specification in the following minor ways:

- Strings are not permitted to contain nested quotes.

- Identifiers cannot contain whitespace.

- Argument separators are constrained to be identifiers (i.e., they cannot be keywords, and they cannot consist of multiple identifiers separated by whitespace.)

- Numbers containing exponents (using the “10” subscript) are not supported.

Identifiers and keywords are case-sensitive. The boldface/underlined keywords of the report are represented by the obvious character sequence, as are most operators. A few operators do not fit into ASCII, and they are mapped as follows:

times *
quotient div
exponential ^
less or equal <=
greater or equal >=
not equal !=
equivalence ==
implication =>
and &
or |
negation !

In addition to the standard functions, the following output functions are supported:

prints(E) prints the string E
printsln(E) prints the string E followed by a newline
printn(E) prints the number E
printnln(E) prints the number E followed by a newline

A prompt in DrRacket’s interactions area accepts whole programs only for the Algol 60 language.

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