jaoswald

This is actually a bit unfair; that notation is from Baker's more mathematical description of the theory. ^oo is the text form of a "superscript infinity symbol", which is the mathematical expression of the COMFY concept "repeat forever", which you could notate however you want in your actual language. In a Lisp-based implementation, the syntax would be something like (seq (load x 1) (loop (< x 11) (print x) (inc x))) Or, in Algol-y terms seq { x = 1; loop { x < 11; print x; x += 1; } } The only tricky thing is that "seq" and "loop" have the special feature of immediately exiting the sequence or loop if any statement inside "fails", which in this example, only the < test can fail. It's this kind of "dumbing down" of things like loop tests that makes the language very simple to compile to machine code. The compiler for the 6502 example fits in a couple pages of code (although it is hard to read because Baker used i & j instead of x & y, and didn't use standard mnemonics for 6502 operations, etc. It took me several hours of reading to really understand it.) With Lispy macros, you can actually create all sorts of nifty "shortcuts." One that he introduces is basically (forx 0 12 <things to do>) which automatically compiles to LDX #0 LOOP CPX #12 BCS EXIT <things to do> INX JMP LOOP EXIT ... and the compiler is smart enough that it can emit LDX #0 LOOP CPX #12 BCC SKIP JMP EXIT SKIP <things to do> INX JMP LOOP EXIT .... in the case where <things to do> takes longer than 128 bytes. Two better articles are the ACM typeset versions of Baker: The COMFY 6502 compiler of the TeX paper and Baker: COMFY---A Comfortable Set of Control Primitives for Machine Language Programming of the COMFY.TXT if you can get through the ACM portal.