PAL (programming language)

PAL, the Pedagogic Algorithmic Language, is a programming language developed at the Massachusetts Institute of Technology in around 1967 to help teach programming language semantics and design.^[1][2] It is a "direct descendant" of ISWIM and owes much of its philosophy to Christopher Strachey.^[3]

Pedagogic Algorithmic Language (PAL)
Paradigms	functional, imperative
Designed by	Original: Peter Landin, James H. Morris, Jr. Redesign: Martin Richards, Thomas J. Barkalow, Arthur Evans, Jr., Robert M. Graham, James Morris, John Wozencraft
Developer	Massachusetts Institute of Technology
First appeared	1967; 58 years ago (1967)
Final release	RPAL 0.2.0-rc1 / 4 October 2006; 18 years ago (2006-10-04)
Typing discipline	dynamic
Scope	lexical
Implementation language	Original: Lisp Redesign: BCPL
Platform	IBM 7090, 7094; System/360
OS	Compatible Time-Sharing System, BOS/360, TOS/360, DOS/360, OS/360
Website	rpal.sourceforge.net
Dialects
Right-reference Pedagogic Algorithmic Language (RPAL)
Influenced by
ISWIM

The initial implementation of PAL, in Lisp, was written by Peter Landin and James H. Morris, Jr. and ran on the Compatible Time-Sharing System (CTSS). It was later redesigned by Martin Richards, Thomas J. Barkalow, Arthur Evans, Jr., Robert M. Graham, James Morris, and John Wozencraft. It was implemented by Richards and Barkalow in BCPL as an intermediate-code interpreter and ran on the IBM System/360; this was called PAL/360.^[4]

RPAL

The Right-reference Pedagogic Algorithmic Language (RPAL), is a functional programming subset of PAL with an implementation on SourceForge.^[5] It is used at the University of Florida to teach the construction of programming languages and functional programming. Programs are strictly functional, with no sequence or assignment operations.