4 ms·

I'd say we should have a proper looping facility that allows for building lists without the fuzz of having special syntax. Common lisp has one. The ITER macro i

by bjoli 7y ago

I'd say we should have a proper looping facility that allows for building lists without the fuzz of having special syntax. Common lisp has one. The ITER macro in CL has is user-extensible, as are racket's for-loops. For non-lazy languages, you either need some sort of loop fusion or a construct like transducers to get similar functionality.

lispm 7y ago
Some LOOP implementations are user-extensible, too.
- bjoli 7y ago
  You made me read sbcls loop implementation. 1900 lines of macro code :)
  - lispm 7y ago
    In SBCL one could use ADD-LOOP-PATH... see also here: https://github.com/sshirokov/CLSQL/blob/master/sql/loop-extension.lisp https://github.com/sshirokov/CLSQL/blob/master/sql/loop-exte...
omaranto 7y ago
Common Lisp's iter or loop macros are special syntax for, among other things, building lists. I think maybe you should have said instead that it's nice when a language let's you add such special syntax in libraries. :)
- bjoli 7y ago
  That is not quite what I want to get across. I think python's list comprehensions are great, but I think they are a shit replacement for a proper looping facility that does everything python's list comprehensions do and more. Racket's for loops are also macros that expand to tail recursive procedures within a letrec, but they are "standard syntax" (in the sense that they are included in the base library) just as loop is.
  - omaranto 7y ago
    Well, Python does have a looping facility that can do everything it's comprehensions can do and more. It's just more special syntax and looks somewhat different from the comprehensions (though they do share keywords where appropriate). I mean, I too prefer loop or iter but Python isn't looping-poor.
    - bjoli 7y ago
      It can't return a list :) It is as if someone said "wow! Returning something from a loop is useful", but instead of going all the way they added special syntax for it.

by bjoli 7y ago

lispm 7y ago

Some LOOP implementations are user-extensible, too.

bjoli 7y ago
You made me read sbcls loop implementation. 1900 lines of macro code :)
- lispm 7y ago
  In SBCL one could use ADD-LOOP-PATH... see also here: https://github.com/sshirokov/CLSQL/blob/master/sql/loop-extension.lisp https://github.com/sshirokov/CLSQL/blob/master/sql/loop-exte...

omaranto 7y ago

Common Lisp's iter or loop macros are special syntax for, among other things, building lists. I think maybe you should have said instead that it's nice when a language let's you add such special syntax in libraries. :)

bjoli 7y ago
That is not quite what I want to get across. I think python's list comprehensions are great, but I think they are a shit replacement for a proper looping facility that does everything python's list comprehensions do and more. Racket's for loops are also macros that expand to tail recursive procedures within a letrec, but they are "standard syntax" (in the sense that they are included in the base library) just as loop is.
- omaranto 7y ago
  Well, Python does have a looping facility that can do everything it's comprehensions can do and more. It's just more special syntax and looks somewhat different from the comprehensions (though they do share keywords where appropriate). I mean, I too prefer loop or iter but Python isn't looping-poor.
  - bjoli 7y ago
    It can't return a list :) It is as if someone said "wow! Returning something from a loop is useful", but instead of going all the way they added special syntax for it.