3 ms·

Quadratic formula in joy: DEFINE quadratic-3 == # a b c => [root1 root2 ] [] cons cons cons

by dvh 8y ago

Quadratic formula in joy: DEFINE quadratic-3 == # a b c => [root1 root2 ] [] cons cons cons # list of parameters [ [ [ [dup * swap] dip * 4 * - sqrt ] # radical [ pop 0 swap - ] # minusb [ 2 * ] ] # divisor [i] map ] infra first [ [ [ + swap / ] # root1 [ - swap / ] ] # root2 [i] map ] infra first.

geocar 8y ago
That doesn't seem very... joyful. In q it's just {(q%x),z%q:-.5y+signum[y]sqrt(yy)-4xz} This is easy to see is correct. How do you know that Joy is correct? I'm trying to mentally execute this. I know I haven't seen Joy before, but I've used Forth, Postscript and Lisp, so I feel like I have a lot to stand on: - cons seems to have the same meaning in lisp, so x y cons -> (x . y) or in Erlangish, [x|y] right? - x [y] dip seems to be y x - [x] [y] infra seems to be the same as [x y] - swap, first, pop, sqrt all seem reasonable - wouldn't [] cons cons cons dup* be better than the extra list with [i] map ] infra first? it's not really clear to me what [i] map is doing... I see how the values have to flow, but it feels like it should be redundant. I feel like it's immediately a lot more (mental) work. It reminds me of tracing forth code before I just gave in and started using variables like a normal person. Is this really the best way to be introduced to Joy? Is this a typical problem that Joy programmers feel is the right way to program (and the right solution?) Am I missing something here?
- exikyut 8y ago
  Formatting note: It will look a bit messier for the things*involving*asterisks to be on their own line (indented two spaces), but that way Arc won't chew them. I'm mentioning this because I can't determine the original text myself.
  - geocar 8y ago
    Yeah, can't edit now. {(q%x),z%q:-.5*y+signum[y]*sqrt(y*y)-4*x*z}
mcguire 8y ago
I haven't done much with concatenate languages, but a rule of thumb is that if you see a bunch of dips, dups, and swaps, then you are probably doing something wrong. Those should be encapsulated in simple definitions.

by dvh 8y ago

geocar 8y ago

That doesn't seem very... joyful. In q it's just {(q%x),z%q:-.5y+signum[y]sqrt(yy)-4xz} This is easy to see is correct. How do you know that Joy is correct? I'm trying to mentally execute this. I know I haven't seen Joy before, but I've used Forth, Postscript and Lisp, so I feel like I have a lot to stand on: - cons seems to have the same meaning in lisp, so x y cons -> (x . y) or in Erlangish, [x|y] right? - x [y] dip seems to be y x - [x] [y] infra seems to be the same as [x y] - swap, first, pop, sqrt all seem reasonable - wouldn't [] cons cons cons dup* be better than the extra list with [i] map ] infra first? it's not really clear to me what [i] map is doing... I see how the values have to flow, but it feels like it should be redundant. I feel like it's immediately a lot more (mental) work. It reminds me of tracing forth code before I just gave in and started using variables like a normal person. Is this really the best way to be introduced to Joy? Is this a typical problem that Joy programmers feel is the right way to program (and the right solution?) Am I missing something here?

exikyut 8y ago
Formatting note: It will look a bit messier for the things*involving*asterisks to be on their own line (indented two spaces), but that way Arc won't chew them. I'm mentioning this because I can't determine the original text myself.
- geocar 8y ago
  Yeah, can't edit now. {(q%x),z%q:-.5*y+signum[y]*sqrt(y*y)-4*x*z}

mcguire 8y ago

I haven't done much with concatenate languages, but a rule of thumb is that if you see a bunch of dips, dups, and swaps, then you are probably doing something wrong. Those should be encapsulated in simple definitions.