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People confuse code at the exploratory phase with final production code. Linked lists are a massively flexible data structure which can be great when you are s

People confuse code at the exploratory phase with final production code. Linked lists are a massively flexible data structure which can be great when you are still feeling your way around a problem domain. Once you have a good sense for the shape of your data it is relatively trivial to go back and update the codebase with performance optimized structures.

samatman 3y ago
That may or may not be the case (that they're great for exploratory code, I have actually mixed feelings about that), but it in fact points directly at the problem I was referring to: using Common Lisp in the idiomatic and expected way involves reading and writing a whole bunch of list processing code. It's not so much that it's a foreign language in the syntactic sense (although it is) but the idiomatic semantics are also pretty foreign to the modern developer. That's a barrier whether or not the promised land is on the far side of the hill.
- hajile 3y ago
  How is the idiom of linked lists foreign to modern devs? You create a list of items. You can add/remove elements to the start, end, and even the middle and even indexing is just as easy with the `nth` function. From a programmer perspective linked lists are universally better. That is to say that if a computer could perform operations on a linked list as quickly and with as little memory as it could for an array, nobody would ever choose to use arrays. We only use arrays because the computer forces us to.
  - gmfawcett 3y ago
    > if a computer could perform operations on a linked list as quickly and with as little memory as it could for an array, nobody would ever choose to use arrays You can start from a false premise, and draw any conclusion you like. If a computer could perform operations on a linked list as quickly and with as little memory as it could for an array, purple unicorns would be grazing on my lawn right now. :)
    - hajile 3y ago
      My assertion is that linked lists map BETTER to the human and WORSE to the computer. The thought experiment is simply a way to prove that fact and is not a premise let alone a false one. If arrays and linked lists had the same performance characteristics, we'd pick linked lists every time because they map better to how humans think about problems while arrays map better to how computers think about problems. Thus we can conclude the exact opposite of the assertion I was responding to. People naturally gravitate toward linked lists then get forcibly re-educated to use arrays because that's what makes the computer happy.
      - CyberDildonics 3y ago
        My assertion is that linked lists map BETTER to the human That's your assertion, but you didn't back it up by anything other than saying you can insert into the middle of a list (which is rare to need and can be done with a sorted map). Thus we can conclude the exact opposite of the assertion I was responding to You can't conclude anything from someone making the same assertion with no evidence over and over. Pragmatically what people use over and over are arrays and hash maps. There's a reason perl, python, lua and javascript all thrived by having arrays and hash maps built in to the core of the language. If you want to loop through something or index by an offset you use an array. If you want to access by key, you use a hash map. In the rare scenario you need to insert into the middle of a specific order, use a sorted map. Modern programming has no place for basic linked lists of granular data and they aren't missed in any sort of real scenario. If can back up what you're saying with any sort of evidence or a specific scenario, go ahead.
CyberDildonics 3y ago
Linked lists in their basic form are essentially obsolete. Having small items linked by pointers on a modern computer means following the pointer, allocation and deallocation are all more expensive than using data. This sounds like a backwards rationalization without a technical explanation. Why would a linked list be any better for 'exploratory' programming? The vast majority of data structures are arrays, hash maps and occasionally a sorted map for the times where you need to insert something in a specific place. What scenario is a linked list valuable in 'exploratory' programming where it wouldn't make more sense to use a different basic data structure?
bigbillheck 3y ago
I've felt my way around a new problem domains many times, and my experience is that a vector and a map will do just fine.

samatman 3y ago

That may or may not be the case (that they're great for exploratory code, I have actually mixed feelings about that), but it in fact points directly at the problem I was referring to: using Common Lisp in the idiomatic and expected way involves reading and writing a whole bunch of list processing code. It's not so much that it's a foreign language in the syntactic sense (although it is) but the idiomatic semantics are also pretty foreign to the modern developer. That's a barrier whether or not the promised land is on the far side of the hill.

hajile 3y ago
How is the idiom of linked lists foreign to modern devs? You create a list of items. You can add/remove elements to the start, end, and even the middle and even indexing is just as easy with the `nth` function. From a programmer perspective linked lists are universally better. That is to say that if a computer could perform operations on a linked list as quickly and with as little memory as it could for an array, nobody would ever choose to use arrays. We only use arrays because the computer forces us to.
- gmfawcett 3y ago
  > if a computer could perform operations on a linked list as quickly and with as little memory as it could for an array, nobody would ever choose to use arrays You can start from a false premise, and draw any conclusion you like. If a computer could perform operations on a linked list as quickly and with as little memory as it could for an array, purple unicorns would be grazing on my lawn right now. :)
  - hajile 3y ago
    My assertion is that linked lists map BETTER to the human and WORSE to the computer. The thought experiment is simply a way to prove that fact and is not a premise let alone a false one. If arrays and linked lists had the same performance characteristics, we'd pick linked lists every time because they map better to how humans think about problems while arrays map better to how computers think about problems. Thus we can conclude the exact opposite of the assertion I was responding to. People naturally gravitate toward linked lists then get forcibly re-educated to use arrays because that's what makes the computer happy.
    - CyberDildonics 3y ago
      My assertion is that linked lists map BETTER to the human That's your assertion, but you didn't back it up by anything other than saying you can insert into the middle of a list (which is rare to need and can be done with a sorted map). Thus we can conclude the exact opposite of the assertion I was responding to You can't conclude anything from someone making the same assertion with no evidence over and over. Pragmatically what people use over and over are arrays and hash maps. There's a reason perl, python, lua and javascript all thrived by having arrays and hash maps built in to the core of the language. If you want to loop through something or index by an offset you use an array. If you want to access by key, you use a hash map. In the rare scenario you need to insert into the middle of a specific order, use a sorted map. Modern programming has no place for basic linked lists of granular data and they aren't missed in any sort of real scenario. If can back up what you're saying with any sort of evidence or a specific scenario, go ahead.

CyberDildonics 3y ago

Linked lists in their basic form are essentially obsolete. Having small items linked by pointers on a modern computer means following the pointer, allocation and deallocation are all more expensive than using data. This sounds like a backwards rationalization without a technical explanation. Why would a linked list be any better for 'exploratory' programming? The vast majority of data structures are arrays, hash maps and occasionally a sorted map for the times where you need to insert something in a specific place. What scenario is a linked list valuable in 'exploratory' programming where it wouldn't make more sense to use a different basic data structure?

bigbillheck 3y ago

I've felt my way around a new problem domains many times, and my experience is that a vector and a map will do just fine.