ALGOL W

ALGOL W is a programming language. It was based on a proposal for ALGOL X by Niklaus Wirth and Tony Hoare as a successor to ALGOL 60 in IFIP Working Group 2.1. When the committee decided that the proposal was not a sufficient advance over ALGOL 60, the proposal was published as A contribution to the development of ALGOL. After making small modifications to the language Wirth supervised a high quality implementation for the IBM/360 at Stanford University that was widely distributed.

It represented a relatively conservative modification of ALGOL 60, adding string, bitstring, complex number and reference to record datatypes and call-by-result passing of parameters, introducing the while statement, replacing switch with the case statement, and generally tightening up the language.

The implementation was written in PL/360, an ALGOL-like assembly language designed by Wirth. The implementation included influential debugging and profiling abilities.

Syntax and semantics

ALGOL W's syntax is built on a subset of the EBCDIC character set. In ALGOL 60 reserved words are distinct lexical items, but in ALGOL W they are merely sequences of characters, and do not need to be stropped. Reserved words and identifiers are separated by spaces. In these ways ALGOL W's syntax resembles that of Pascal and later languages.