On compiling. (Was a way off topic subject)

Paul K got it right: "Any language can be interpreted or compiled. For some languages, like LISP and TECO, interpreting is a rather natural implementation techniques, while for others (C, ALGOL) compilation is the obvious answer. But either is possible." A few quick notes... Back around 1973, I wrote a compiler for InterLISP on the Burroughs B6700, with the target code being a new P-code invented just for LISP (by, I think, Bill Gord, based on Peter Deutsch and Ken Bowles P-code work). Yeah, some parts of the P-code machine had to invoke the interpreter, but that's philosophically no different than the next note... Around 1977/1978, Hewlett-Packard released the source code for their COBOL compiler for the HP 3000. My friend looked at the source and said: every statement compiles into a bunch of subroutine calls! So, technically....it was a compiler. But, essentially no machine code was emitted :) In 1984, HP announced their PA-RISC systems (HP 3000 and HP 9000), and that their ALGOL-like language, SPL, used by them and customers on the HP 3000, would not be ported to PA-RISC (because "it wasn't possible"). We looked at it and said: we can. And, we did (without the "subroutine call" mechanism :) In some cases, we emulate a 16-bit wide CISC architecture (e.g., if you use the SPL construct "ASSEMBLE (...)", we compile it...into PA-RISC code emulating the old architecture). It's still in use today, and can now emit either PA-RISC code or C source code (for a form of cross-compiling). What HP missed, and many people miss, is that any language can be compiled. The main question one might ask is the degree of closeness to machine code that's emitted :) Stan