PLATTS@Wharton-10@sri-unix (10/22/82)
From: PLATTS at Wharton-10 (Steve Platt) first of all, this is mostly a bunch of silliness comparing "algebraic" to "rpn"; I tend to use TI (cheaper), although I haven't bought one in years (the '59, when it was <$50, was my last). I have no problems going between notations, and very few people I know do. As to the desire for a lisp-like HP machine; well, the RPN is practically there! Consider that it is a parenthesis-free notation, and the grammer you desire for the machine: expr -> value | variable expr -> op exprlist exprlist -> expr ENTER | expr ENTER exprlist is not significantly different from the current HP RPN: expr -> value | variable expr -> expr op | expr ENTER exprmid expr op exprmid -> expr op | expr op exprmid | <empty> (ugh, how technical). But the main idea is that by repeating the "op expr" section, you achieve the same effect. The main problem with the entire system is the HP's limited stack space (although this may be old; I haven't used one thoroughly in years)... Do the newer HPs have a stack greater than 4 deep? -steve platt
hdj (10/23/82)
Speaking of "HP lisp machines," one of my schoolmates (and now colleague) wrote a nearly-complete version of tiny Lisp for his HP-41c. This was a couple of years ago, before the advent of the quad memory module. Believe it. -h burdvax!hdj
puder (10/25/82)
Before all you HP41 users start flooding Herb with requests for references to the lisp (that I wrote), it was EXTREMELY TINY!!. It was done for a project in an advanced LISP course (@ Syracuse U.) just to see how it would work out. It just barely ran. That is, for example, it could reverse a three element list in a few minutes if the garbage collection didn't happen when the stack was already large. So don't expect to see it in the user's library. The only way it could ever do anything would be for HP to be convinced that "Lisp is good" and put it in microcode. This exercise does prove, though, that LISP can be put in a very small box. (Karl Puder) ...!lime!burdvax!puder