5 ms·

LOOP gets weird flack from some purist mindset. There's no issue with it in practice.

vegai_ 5y ago
Yeah, the other, possibly worse, problem is that experienced common lisp programmers think that LOOP is ok ;)
maydup-nem 5y ago
purist? no, it's a very practical mindset. if you are into lisp, you should already appreciate the power of parenthesis. i literally have to spend time parsing the barren (longish) loop macros to understand wth is going on and what keyword is suppossed to stick to where. in other, totally unrelated news, forget about customizability and embrace the ever-crappy indentation (especially with aggressive-indent) and the awful non-sexp-based editing. what looks like purism is in fact guided by simple pain avoidance. no, fren, iterate all the way. it is regular common lisp code and doesn't make you context switch due to some _obviously_ misguided DSL design. i don't understand why some lispers are so adamantly supportive of LOOP. what's more, some of them _despise_ iterate (because reasons). i just don't get it. PS As a bonus, iterate has an actually usable manual [1]. For LOOP, i have to go to gigamonkeys and whatnot. [1] https://iterate.common-lisp.dev/doc/index.html#Top https://iterate.common-lisp.dev/doc/index.html#Top
- taeric 5y ago
  To each their own. I'm a huge fan of LOOP. Is very easy to read, feeling much more natural to how I think about those sections of code.
  - maydup-nem 5y ago
    Yes, I was a fan of LOOP too, until I found iterate. I mean, we are discussing the two things comparatively here, aren't we? So, how is loop better than iterate? Iterate has nearly the same semanitcs as LOOP. It's basically LOOP on s-exprs, with some handy idioms sprinkled in. But often times the match is 1-1. So, how is the absence of sexprs making anything easiers to read or write? It makes it harder for me in both cases.
    - taeric 5y ago
      I'll try iterate. For me it is just that loop is already very easy to read. Moving all things to s exprs doesn't seem like it would be that big of a deal. And I should say that the construct that I find easiest is the "then" clause. (Loop repeat 8 For a = 0 then b For b = 1 then c For c = 1 then (+ a b) Collect a) That just reads very easily to me. (Typed on phone...)
      - maydup-nem 5y ago
        First of all, if you are going to try it out, I recommend using this macro: (defmacro itr (&rest rest) `(iterate:iterate ,@rest)) because it keeps all the clauses on the same indentation level. Now, to the translation: iterate has previous clause. https://iterate.common-lisp.dev/doc/Previous-Values-of-Driver-Variables.html https://iterate.common-lisp.dev/doc/Previous-Values-of-Drive... which may help translate the loop form you provided into this: (itr (repeat 8) (for a previous b initially 0) (for b previous c initially 1) (for c = (+ a b)) (collect a)) However, if you wanted that exact syntax, you could try: (defmacro-clause (FOR var = init-value THEN form) `(progn (with ,var = ,init-value) (after-each (setf ,var ,form)))) to get a direct translation: (itr (repeat 8) (for a = 0 then b) (for b = 1 then c) (for c = 1 then (+ a b)) (collect a)) > Moving all things to s exprs doesn't seem like it would be that big of a deal. One of the biggest things you will "miss" from LOOP is the do keyword. The control structures is just regular lisp code. Also, I found generators to be pretty handy (not often, but I am glad I had them when it was called for). I mean, it's not exactly groundbreaking, but it does make a difference especially that a looping construct is probably the heaviest-used macro. You can certainly get away with LOOP, but I see iterate as more or less how LOOP should've been done. I also recommend reading this short discussion in the manual https://iterate.common-lisp.dev/doc/Don_0027t-Loop-Iterate.html#Don_0027t-Loop-Iterate https://iterate.common-lisp.dev/doc/Don_0027t-Loop-Iterate.h...
        taeric 5y ago
        Previous doesn't have the same flow, so does feel more cumbersome than I'd like. (That is, I specifically like the left to right flow of "this then that" for variables.) I do have a softspot for how this is embracing the parens. :D This is funny in that it seems to dodge the biggest complaint of loop, that it has different syntax for lists and vectors/hashtables.
da39a3ee 5y ago
Why does this crazy macro exist for one part of the language but not others? It feels obviously out of place and gives you the feeling that you're using a legacy language with historical oddities rather than a coherently designed system.
- taeric 5y ago
  Me thinks you just haven't looked at more parts. FORMAT, in particular, is just as dense.
  - maydup-nem 5y ago
    Is there an alternative to FORMAT?
    - taeric 5y ago
      I mean. Not really, though I have seen folks make a herculean effort with print and friends.

Yeah, the other, possibly worse, problem is that experienced common lisp programmers think that LOOP is ok ;)

purist? no, it's a very practical mindset. if you are into lisp, you should already appreciate the power of parenthesis. i literally have to spend time parsing the barren (longish) loop macros to understand wth is going on and what keyword is suppossed to stick to where. in other, totally unrelated news, forget about customizability and embrace the ever-crappy indentation (especially with aggressive-indent) and the awful non-sexp-based editing. what looks like purism is in fact guided by simple pain avoidance. no, fren, iterate all the way. it is regular common lisp code and doesn't make you context switch due to some _obviously_ misguided DSL design. i don't understand why some lispers are so adamantly supportive of LOOP. what's more, some of them _despise_ iterate (because reasons). i just don't get it. PS As a bonus, iterate has an actually usable manual [1]. For LOOP, i have to go to gigamonkeys and whatnot. [1] https://iterate.common-lisp.dev/doc/index.html#Top https://iterate.common-lisp.dev/doc/index.html#Top

taeric 5y ago
To each their own. I'm a huge fan of LOOP. Is very easy to read, feeling much more natural to how I think about those sections of code.
- maydup-nem 5y ago
  Yes, I was a fan of LOOP too, until I found iterate. I mean, we are discussing the two things comparatively here, aren't we? So, how is loop better than iterate? Iterate has nearly the same semanitcs as LOOP. It's basically LOOP on s-exprs, with some handy idioms sprinkled in. But often times the match is 1-1. So, how is the absence of sexprs making anything easiers to read or write? It makes it harder for me in both cases.
  - taeric 5y ago
    I'll try iterate. For me it is just that loop is already very easy to read. Moving all things to s exprs doesn't seem like it would be that big of a deal. And I should say that the construct that I find easiest is the "then" clause. (Loop repeat 8 For a = 0 then b For b = 1 then c For c = 1 then (+ a b) Collect a) That just reads very easily to me. (Typed on phone...)
    - maydup-nem 5y ago
      First of all, if you are going to try it out, I recommend using this macro: (defmacro itr (&rest rest) `(iterate:iterate ,@rest)) because it keeps all the clauses on the same indentation level. Now, to the translation: iterate has previous clause. https://iterate.common-lisp.dev/doc/Previous-Values-of-Driver-Variables.html https://iterate.common-lisp.dev/doc/Previous-Values-of-Drive... which may help translate the loop form you provided into this: (itr (repeat 8) (for a previous b initially 0) (for b previous c initially 1) (for c = (+ a b)) (collect a)) However, if you wanted that exact syntax, you could try: (defmacro-clause (FOR var = init-value THEN form) `(progn (with ,var = ,init-value) (after-each (setf ,var ,form)))) to get a direct translation: (itr (repeat 8) (for a = 0 then b) (for b = 1 then c) (for c = 1 then (+ a b)) (collect a)) > Moving all things to s exprs doesn't seem like it would be that big of a deal. One of the biggest things you will "miss" from LOOP is the do keyword. The control structures is just regular lisp code. Also, I found generators to be pretty handy (not often, but I am glad I had them when it was called for). I mean, it's not exactly groundbreaking, but it does make a difference especially that a looping construct is probably the heaviest-used macro. You can certainly get away with LOOP, but I see iterate as more or less how LOOP should've been done. I also recommend reading this short discussion in the manual https://iterate.common-lisp.dev/doc/Don_0027t-Loop-Iterate.html#Don_0027t-Loop-Iterate https://iterate.common-lisp.dev/doc/Don_0027t-Loop-Iterate.h...
      - taeric 5y ago
        Previous doesn't have the same flow, so does feel more cumbersome than I'd like. (That is, I specifically like the left to right flow of "this then that" for variables.) I do have a softspot for how this is embracing the parens. :D This is funny in that it seems to dodge the biggest complaint of loop, that it has different syntax for lists and vectors/hashtables.

da39a3ee 5y ago

Why does this crazy macro exist for one part of the language but not others? It feels obviously out of place and gives you the feeling that you're using a legacy language with historical oddities rather than a coherently designed system.

taeric 5y ago
Me thinks you just haven't looked at more parts. FORMAT, in particular, is just as dense.
- maydup-nem 5y ago
  Is there an alternative to FORMAT?
  - taeric 5y ago
    I mean. Not really, though I have seen folks make a herculean effort with print and friends.