GNU is not UNIX is not UNIX is not UNIX is not UNIX is not UNIX is not UNIX is not UNIX is not UNIX is not UNIX is not UNIX is not UNIX is not UNIX is not UNIX is not UNIX is not UNIX is not UNIX is not UNIX is not UNIX is not UNIX is not UNIX is not UNIX is not UNIX is not UNIX is not UNIX is not UNIX is not UNIX is not UNIX is not UNIX is not UNIX is not UNIX is not UNIX is not UNIX is not UNIX is not UNIX is not UNIX is not UNIX is not UNIX is not UNIX is not UNIX is not UNIX is not UNIX is not UNIX is not UNIX is not UNIX is not UNIX is not UNIX is not UNIX is not UNIX is not UNIX is not UNIX is not UNIX is not UNIX is not UNIX is not UNIX is not UNIX is not UNIX is not UNIX is not UNIX is not UNIX is not UNIX is not UNIX is not UNIX is not UNIX is not UNIX is not UNIX is not UNIX is not UNIX is not UNIX is not UNIX is not UNIX is not UNIX is not UNIX is not UNIX is not UNIX[Maximum call stack size exceeded]
A tail-recursive version written in OCaml that should not reach stack limits easily. (Not an expert in OCaml, so this might be stupid. But I tried it with 10000 iterations, and it worked without any issues.)
let gnu =
let rec aux s = function
| 0 -> s
| n -> aux (s^" is Not Unix") (n-1)
in aux "GNU";;
Not an OCaml expert either but that looks tail recursive, you’re never going to blow the stack.
You can tell by how after the recursive within aux, its result does not get used within the function. That means that the compiler doesn’t need to push a return address to the stack as the only code that would be at that address is instructions to pop another address and return there, we can short-circuit all that and jump from the r base case (0) directly to where aux(10000) is supposed to return to instead of taking 10000 dumb steps (like practically all procedural languages do because they don’t have tail call optimisation).
This would’ve been different if you had concatenated the string not as an argument to aux.
That was the idea. But I’m not a functional programmer (not a programmer by profession at all lol), so I might’ve done something stupid. Hence the disclaimer. Thanks for confirming.
OCaml certainly isn’t a bad language to learn for a non-professional. It’s almost painfully sensible and well-engineered, you’re far away from hype train nonsense and startup production jank but also not out in the “the purpose of this language is to be beautiful and earn me a PhD” territory, OCaml definitely is a production language.
I thought Tail recursion just gets turned into an iterative loop by the compiler? Hence why you won’t get a stack overflow. And since in procedural languages you can just use a loop in place of a tail recursive function you would never run into this problem, right? At least this is how it was taught to me when I was learning about it in lisp.
Yes you still need the loop part I skipped over that one, only focussing on the “why no return address on the stack” part. It’s what you need to focus on to see whether a recursive call is in a tail position and if it is the compiler does the rest no need to worry about that part.
GNU is not UNiplexed Information Computing System is not UNiplexed Information Computing System is not UNiplexed Information Computing System is not UNiplexed Information Computing System is not UNiplexed Information Computing System is not UNiplexed Information Computing System is not UNiplexed Information Computing System is not UNiplexed Information Computing System is not UNiplexed Information Computing System is not UNiplexed Information Computing System is not UNiplexed Information Computing System is not UNiplexed Information Computing System is not UNiplexed Information Computing System is not UNiplexed Information Computing System is not UNiplexed Information Computing System is not UNiplexed Information Computing System
Which, if the ubuntu link is clicked, then drops you into the the real archive root… but the link is “appended” to the new path, but the same link is reproduced in the “new” folder. Click it again, and another segment added to your current path even though you’re in the same root archive, ad nauseam.
I couldn’t find this misconfiguration on stackoverflow, which leads me to believe someone at ubuntu is doing something especially special here.
I’d bet that they symlinked /ubuntu to the server’s home root - probably for continuity with some previous file structure. It sure looks silly, but I’m sure the reasons for doing it were pretty reasonable.
GNU is not UNIX is not UNIX is not UNIX is not UNIX is not UNIX is not UNIX is not UNIX is not UNIX is not UNIX is not UNIX is not UNIX is not UNIX is not UNIX is not UNIX is not UNIX is not UNIX is not UNIX is not UNIX is not UNIX is not UNIX is not UNIX is not UNIX is not UNIX is not UNIX is not UNIX is not UNIX is not UNIX is not UNIX is not UNIX is not UNIX is not UNIX is not UNIX is not UNIX is not UNIX is not UNIX is not UNIX is not UNIX is not UNIX is not UNIX is not UNIX is not UNIX is not UNIX is not UNIX is not UNIX is not UNIX is not UNIX is not UNIX is not UNIX is not UNIX is not UNIX is not UNIX is not UNIX is not UNIX is not UNIX is not UNIX is not UNIX is not UNIX is not UNIX is not UNIX is not UNIX is not UNIX is not UNIX is not UNIX is not UNIX is not UNIX is not UNIX is not UNIX is not UNIX is not UNIX is not UNIX is not UNIX is not UNIX is not UNIX is not UNIX[Maximum call stack size exceeded]
A tail-recursive version written in OCaml that should not reach stack limits easily. (Not an expert in OCaml, so this might be stupid. But I tried it with 10000 iterations, and it worked without any issues.)
Not an OCaml expert either but that looks tail recursive, you’re never going to blow the stack.
You can tell by how after the recursive within aux, its result does not get used within the function. That means that the compiler doesn’t need to push a return address to the stack as the only code that would be at that address is instructions to pop another address and return there, we can short-circuit all that and jump from the r base case (0) directly to where aux(10000) is supposed to return to instead of taking 10000 dumb steps (like practically all procedural languages do because they don’t have tail call optimisation).
This would’ve been different if you had concatenated the string not as an argument to aux.
That was the idea. But I’m not a functional programmer (not a programmer by profession at all lol), so I might’ve done something stupid. Hence the disclaimer. Thanks for confirming.
OCaml certainly isn’t a bad language to learn for a non-professional. It’s almost painfully sensible and well-engineered, you’re far away from hype train nonsense and startup production jank but also not out in the “the purpose of this language is to be beautiful and earn me a PhD” territory, OCaml definitely is a production language.
I thought Tail recursion just gets turned into an iterative loop by the compiler? Hence why you won’t get a stack overflow. And since in procedural languages you can just use a loop in place of a tail recursive function you would never run into this problem, right? At least this is how it was taught to me when I was learning about it in lisp.
Yes you still need the loop part I skipped over that one, only focussing on the “why no return address on the stack” part. It’s what you need to focus on to see whether a recursive call is in a tail position and if it is the compiler does the rest no need to worry about that part.
GNU is not UNiplexed Information Computing System is not UNiplexed Information Computing System is not UNiplexed Information Computing System is not UNiplexed Information Computing System is not UNiplexed Information Computing System is not UNiplexed Information Computing System is not UNiplexed Information Computing System is not UNiplexed Information Computing System is not UNiplexed Information Computing System is not UNiplexed Information Computing System is not UNiplexed Information Computing System is not UNiplexed Information Computing System is not UNiplexed Information Computing System is not UNiplexed Information Computing System is not UNiplexed Information Computing System is not UNiplexed Information Computing System
http://ubuntu.ubuntu.ubuntu.ubuntu.ubuntu.ubuntu.ubuntu.ubuntu.ubuntu.ubuntu.ubuntu.ubuntu.ubuntu.ubuntu.ubuntu.ubuntu.ubuntu.ubuntu.ubuntu.ubuntu.ubuntu.ubuntu.ubuntu.ubuntu.ubuntu.ubuntu.ubuntu.ubuntu.ubuntu.ubuntu.ubuntu.ubuntu.ubuntu.archive.ubuntu.com/ubuntu/ubuntu/ubuntu/ubuntu/ubuntu/ubuntu/ubuntu/ubuntu/ubuntu/ubuntu/ubuntu/ubuntu/ubuntu/ubuntu/ubuntu/ubuntu/ubuntu/ubuntu/ubuntu/ubuntu/ubuntu/ubuntu/ubuntu/ubuntu/ubuntu/ubuntu/ubuntu/ubuntu/ubuntu/ubuntu/ubuntu/ubuntu/ubuntu/ubuntu/ubuntu/ubuntu/ubuntu/ubuntu/ubuntu/ubuntu/ is a totally valid link
That’s great, it even goes deeper
http://ubuntu.ubuntu.ubuntu.ubuntu.ubuntu.ubuntu.ubuntu.ubuntu.ubuntu.ubuntu.ubuntu.ubuntu.ubuntu.ubuntu.ubuntu.ubuntu.ubuntu.ubuntu.ubuntu.ubuntu.ubuntu.ubuntu.ubuntu.ubuntu.ubuntu.ubuntu.ubuntu.ubuntu.ubuntu.ubuntu.ubuntu.ubuntu.ubuntu.archive.ubuntu.com/ubuntu/ubuntu/ubuntu/ubuntu/ubuntu/ubuntu/ubuntu/ubuntu/ubuntu/ubuntu/ubuntu/ubuntu/ubuntu/ubuntu/ubuntu/ubuntu/ubuntu/ubuntu/ubuntu/ubuntu/ubuntu/ubuntu/ubuntu/ubuntu/ubuntu/ubuntu/ubuntu/ubuntu/ubuntu/ubuntu/ubuntu/ubuntu/ubuntu/ubuntu/ubuntu/ubuntu/ubuntu/ubuntu/ubuntu/ubuntu/dists/mantic-backports/universe/debian-installer/binary-i386/by-hash/SHA256/e7ab72b8f37c7c9c9f6386fb8e3dfa40bf6fe4b67876703c5927e47cb8664ce4
Wtf
How is this a thing??
Yeah some kind of fucky configuration.
The root is:
http://archive.ubuntu.com
Which, if the
ubuntu
link is clicked, then drops you into the the real archive root… but the link is “appended” to the new path, but the same link is reproduced in the “new” folder. Click it again, and another segment added to your current path even though you’re in the same root archive, ad nauseam.I couldn’t find this misconfiguration on stackoverflow, which leads me to believe someone at ubuntu is doing something especially special here.
I’d bet that they symlinked
/ubuntu
to the server’s home root - probably for continuity with some previous file structure. It sure looks silly, but I’m sure the reasons for doing it were pretty reasonable.