Wirth Evolution
PL360, Algol W, and EULER are additional languages created by Wirth. PL360 was a programming language that provided low level access to IBM&#x27;s 360 mainframe hardware, Algol W made a number of improvements to Algol 60 to make it more practical--I think it was a reaction to Algol 68 which was very complex for the time and consequently ended up with very few compilers[1]. I don&#x27;t know anything about Euler.<p>I had the pleasure of meeting Nicklaus Wirth around 1977 at Texas Instruments. I worked in a department that had developed a PASCAL compiler for TI processors; Wirth had been invited to give us a demonstration of his Pascal&#x2F;Modula based system. I don&#x27;t remember the details of the impressive presentation, but I do remember him telling the joke about his name: in Europe they call him by name (sounds like &quot;Virt&quot;) while Americans call him by value saying &quot;Worth&quot; for his last name.<p>I enjoyed his books a great deal and read every published paper of his that I could get my hands on. I learned a great deal from his clear writing during formative years in my programming career.<p>--- below this line, I stray off topic ---<p>[1] For example, the Algol 68 Report used a two-level grammar (Van Wijngaarden grammar) to describe the syntax of Algol 68. Such a two level grammar had one set of rules that would expand into an arbitrarily large different set of productions describing the syntax of an Algol 68 program. Vw grammars are capable of defining recursively enumerable languages. In the Algol 68 report it was hoped that more language features could be precisely described by such a formal grammar rather than by prose that stated requirements like &quot;variable must be declared before use&quot;.<p>While admirable, such a goal isn&#x27;t practical because the set of recursively enumerable languages is essentially equivalent to the set of Turing machine programs or Chomsky&#x27;s type 0 grammars. We don&#x27;t want compilers to be burdened with solving the impossible to solve halting problem.