ALGOL W

By now mostly forgotten, but at the time a superior implementation of ALGOL available for the IBM System/360 and based on the earlier Euler ALGOL variant. Source code for the Stanford distribution can be found here. Algol-W like its immediate predecessor Euler Algol was written by Niklaus Wirth in PL/360, and is in turn the immediate predecessor to Pascal, although the latter language is smaller as it was not intended to be a systems language like Algol-W and Euler. Notably the original Prolog implementation, one of the few programming languages today that are not related in any way to ALGOL was actually developed in Algol-W.

Links

 * The original Algol-W proposals are now lost, but the Manual still exists.