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> The great thing about toys is they are very easy to put down for a while and then pick back up again later with very little effort. That matches my experienc

> The great thing about toys is they are very easy to put down for a while and then pick back up again later with very little effort. That matches my experience. I've written programs in Haskell, and it was very satisfying. But going back to the project after 6 months of work in other languages was very hard. I took some time to remember the concepts, the abstractions and what the cryptic operators meant in their contexts. I've kept away of Rust for this reason: maintenance would be hard if I only dabble episodicly in Rust. On the other side, my own experience with Lua was not very nice. I contributed (and patched for my needs) Koreader, an ebook reader with 180k lines of Lua. The lack of explicit types and data structures was a strong impediment. And the language has subtle traps... Everything is a table, but not all tables are equals: some tables are sequences (indexed by 1..n) with special operators (like # whose result is undetermined for other tables (which hurts like the famous Undefined Behavior of C++). With Lua, simple questions like "Is this table empty?" or "What is the size of a table?" are too hard for beginners. So, complex artefacts are hard to go back after a long break, but many toys break easily when you come back after a pause, having forgotten how fragile they were.

nequo 2y ago
I find Rust much better on this front than Haskell. Haskell has a much stronger culture of using library-specific operators and abbreviations for function, variable, and type names, than Rust does. In Rust, you can’t even define a custom operator. If you understand borrowing and some of the basic traits, you’re a long way there. There aren’t new DSLs to learn or relearn, and the documentation is good at closing any gaps that open up while you’re away from Rust.
samatman 2y ago
> Everything is a table, but not all tables are equals: some tables are sequences (indexed by 1..n) with special operators (like # whose result is undetermined for other tables (which hurts like the famous Undefined Behavior of C++). > #{} 0
- int_19h 2y ago
  {} is explicitly defined as a sequence of length 0 by the language spec. But for any table which has a nil in it between two non-nil values - i.e. non-sequences - there's basically no guarantees on which one of the several possible values # will return. https://www.lua.org/manual/5.4/manual.html#3.4.7 https://www.lua.org/manual/5.4/manual.html#3.4.7
  - samatman 2y ago
    Yes, that's true. What isn't true is that "some tables are sequences" which have "special operators" whose results are "undetermined for other tables". A table has an array portion, it has contents or it doesn't, you can check this as I illustrated (I didn't intend it to check if the table is entirely empty, the sibling comment to yours shows how to do that). `#` works on any table. It is in fact the case that if you start sticking `nil` into the contiguous array portion of the table, you'll have problems: `#` and `ipairs` won't work correctly. That's part of why `false` (and therefore `true`) were added to the language. It's a quirk you have to know to use Lua effectively, that's all. In years of programming Lua, I've never had a bug which originated from adding `nil` within the array portion. As the only composite data structure in the entire language, it's reasonable to expect people to learn how they work if they're using Lua. The one correct observation in the post I was replying is that there's no obvious or cheap way to find the number of entries in a table (other than the array portion). Luajit has `table.nkeys`, and that should have been imported into stock Lua. There are a lot of anecdotes in this thread which amount to "my experience with Lua was as a means to an end: I was using it as a scripting language for something else, and it subverted my expectations in some way or another (mostly by not being Python)". Understandable in a way, but it should take half a day at most to read the entire manual and the online edition of Programming in Lua, and there's no sense in blaming the language because a user wanted to get something done and figured they would skip that part.
    - int_19h 2y ago
      The point is that # is basically unusable for non-sequence tables because there are no guarantees on which border it will return. But at the same time, when that happens, you do not get any clear error, either. That is the nasty part here, and it is exacerbated by the lack of any kind of static or even dynamic typing to distinguish sequences from non-sequences - e.g. Python is also a very dynamic language, and has a rich set of built-in data structures, but there's no point at which len() will silently do the wrong thing for any of them. Either a given collection type supports it, in which case you get a meaningful value, or it doesn't, in which case you get an error. In Lua, if you ever get an invalid table as input, you will silently get the wrong value which is nevertheless indexable, and so when you use it you get another wrong value etc, and eventually your computation just produces garbage output with no obvious clues as to where the error was introduced. That is a clear design defect in the language. As far as personal experiences, I can't speak for OP, but I've learned Lua in early 00s, long before Python. As languages go, I don't think it's the worst dynamically typed language by far - it sure beats JavaScript, and Python could learn some things from it as well. But when it comes to long-term maintainability of large amounts of code, it is subpar.

nequo 2y ago

I find Rust much better on this front than Haskell. Haskell has a much stronger culture of using library-specific operators and abbreviations for function, variable, and type names, than Rust does. In Rust, you can’t even define a custom operator. If you understand borrowing and some of the basic traits, you’re a long way there. There aren’t new DSLs to learn or relearn, and the documentation is good at closing any gaps that open up while you’re away from Rust.

samatman 2y ago

> Everything is a table, but not all tables are equals: some tables are sequences (indexed by 1..n) with special operators (like # whose result is undetermined for other tables (which hurts like the famous Undefined Behavior of C++). > #{} 0

int_19h 2y ago
{} is explicitly defined as a sequence of length 0 by the language spec. But for any table which has a nil in it between two non-nil values - i.e. non-sequences - there's basically no guarantees on which one of the several possible values # will return. https://www.lua.org/manual/5.4/manual.html#3.4.7 https://www.lua.org/manual/5.4/manual.html#3.4.7
- samatman 2y ago
  Yes, that's true. What isn't true is that "some tables are sequences" which have "special operators" whose results are "undetermined for other tables". A table has an array portion, it has contents or it doesn't, you can check this as I illustrated (I didn't intend it to check if the table is entirely empty, the sibling comment to yours shows how to do that). `#` works on any table. It is in fact the case that if you start sticking `nil` into the contiguous array portion of the table, you'll have problems: `#` and `ipairs` won't work correctly. That's part of why `false` (and therefore `true`) were added to the language. It's a quirk you have to know to use Lua effectively, that's all. In years of programming Lua, I've never had a bug which originated from adding `nil` within the array portion. As the only composite data structure in the entire language, it's reasonable to expect people to learn how they work if they're using Lua. The one correct observation in the post I was replying is that there's no obvious or cheap way to find the number of entries in a table (other than the array portion). Luajit has `table.nkeys`, and that should have been imported into stock Lua. There are a lot of anecdotes in this thread which amount to "my experience with Lua was as a means to an end: I was using it as a scripting language for something else, and it subverted my expectations in some way or another (mostly by not being Python)". Understandable in a way, but it should take half a day at most to read the entire manual and the online edition of Programming in Lua, and there's no sense in blaming the language because a user wanted to get something done and figured they would skip that part.
  - int_19h 2y ago
    The point is that # is basically unusable for non-sequence tables because there are no guarantees on which border it will return. But at the same time, when that happens, you do not get any clear error, either. That is the nasty part here, and it is exacerbated by the lack of any kind of static or even dynamic typing to distinguish sequences from non-sequences - e.g. Python is also a very dynamic language, and has a rich set of built-in data structures, but there's no point at which len() will silently do the wrong thing for any of them. Either a given collection type supports it, in which case you get a meaningful value, or it doesn't, in which case you get an error. In Lua, if you ever get an invalid table as input, you will silently get the wrong value which is nevertheless indexable, and so when you use it you get another wrong value etc, and eventually your computation just produces garbage output with no obvious clues as to where the error was introduced. That is a clear design defect in the language. As far as personal experiences, I can't speak for OP, but I've learned Lua in early 00s, long before Python. As languages go, I don't think it's the worst dynamically typed language by far - it sure beats JavaScript, and Python could learn some things from it as well. But when it comes to long-term maintainability of large amounts of code, it is subpar.