Linked lists considered harmful

  ↑    slava_pestov 4 points 5 hours ago [-]
  ↓    A perfect illustration of why single linked lists are simply the wrong data structure in
        99% of cases. Just use arrays and you won't have to choose between tail recursion, and
        front-to-back iteration order.
        permalink report reply

>>40
AND SOMEONE ALREADY SUBMITTED IT AS A THREAD?!
http://www.reddit.com/r/programming/comments/9supb/considered_harmful_slava_pestov_single_linked/

>>41
submitted 3 hours ago by Seppler90000

ಠ_ಠ

your face is considered harmful

>>38
Not if I go out first, which I did.

>>38
I disagree because there's a point where you can factor out functions but you can't really come up with meaningful names for them, so you end up with lots of tiny functions with weird ass names, but in concatenative languages you kinda have no choice but to do just that, because otherwise the stack juggling mental overhead that would ensue would drive you (and everyone who touches your code) insane. Some times it's easier to come up with meaningful variable names than names for artificially factored out functions. Plus I was asking for an example of extreme factoring's superiority over sensible variable naming, specifically one that coul only work in concatenative languages. That example right there can be reproduced in any OO language or  any language that supports currying.

>>41
MrVacBob responded!

>>38
Here's a factoring challenge for you. I have this Forth code here (modified from a piece of Forth code I wrote some time ago, works on GForth) that makes extensive use of local variables. If you can turn this into a readable, variable-free, more finely factored code, I will totaly believe everything you said about the concatenative approach. I would ask that you keep it in Forth so we could test the advantages of concatenativity alone.

: exchange ( addr1 addr2 -- ) dup c@ rot dup c@ -rot c! swap c! ;
\ exchanges the contents of two character addresses.

: permuts_do_loop { set set_size permut permut_size action -- }
   set permut permut_size + = if
       permut permut_size action execute
   else
      set_size 1- dup to set_size for
         set dup i chars + 2dup exchange
         set char+ set_size permut permut_size action recurse
         exchange
      next
   endif
;

: permuts_do ( set set_size permut_size action ) 2>r over 2r> permuts_do_loop ;

s" 0123456789" 2constant 0_to_9

0_to_9 4 :noname type cr ; permuts_do
0_to_9 type cr bye

Slava is a motherfucking troll, and his pet language is awful.

/thread

>>45
I disagree because there's a point where you can factor out functions but you can't really come up with meaningful names for them, so you end up with lots of tiny functions with weird ass names, but in concatenative languages you kinda have no choice but to do just that, because otherwise the stack juggling mental overhead that would ensue would drive you (and everyone who touches your code) insane. Some times it's easier to come up with meaningful variable names than names for artificially factored out functions.
Example?

Plus I was asking for an example of extreme factoring's superiority over sensible variable naming, specifically one that coul only work in concatenative languages. That example right there can be reproduced in any OO language or  any language that supports currying.
That was an example of a readable long function.

>>49
Example?
See >>47

>>40
Aw, man TTFF?

bump

>>52
I am very disappointed in you :(

>>53
And I'm disapointed in >>38,49. Such is life.

>>54
>>38,49 here. I'd like to try your challenge, but I haven't had time yet.

>>55
Ok then. Here's a slightly cleaner looking version.

: exchange ( addr1 addr2 -- ) tuck c@ -rot tuck c@ swap c! c! ;
\ exchanges the contents of two character addresses.

: permuts_do_loop { set set_size permut permut_size action -- }
   set permut permut_size + = if
       permut permut_size action execute
   else
      set_size 0 +do
         set dup i chars + 2dup exchange
         set char+ set_size 1- permut permut_size action recurse
         exchange
      loop
   endif
;

: permuts_do ( set set_size permut_size action -- )
   2>r over 2r> permuts_do_loop
;

s" 0123456789" 2constant 0_to_9

0_to_9 4 :noname type cr ; permuts_do
0_to_9 type cr bye

60 Name: Anonymous 2011-02-03 4:24

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