Opal (programming language)

This article is about the functional programming language. For the Ruby interpreter, see Ruby (programming language) § Alternative implementations.

OPAL (OPtimized Applicative Language) is a functional programming language first developed at Technische Universität Berlin. There is a later framework for static code analysis also called Opal.

Example program

This is an example OPAL program, which calculates the GCD recursively.

Signature file (declaration)

SIGNATURE GCD FUN GCD: nat ** nat -> nat

Implementation file (definition)

IMPLEMENTATION GCD IMPORT Nat COMPLETELY DEF GCD(a,b) == IF a % b = 0 THEN b ELSE IF a-b < b THEN GCD(b,a-b) ELSE GCD(a-b,b) FI FI

External links

• The OPAL Home Page, archived, last modified 30 September 2010.
• OPAL Installation Guide, archived.