3 ms·

If you're quite used to Haskell, it's nbd. If you're coming from another language with for loops and someone tells you it's a for loop, you might be surprised t

If you're quite used to Haskell, it's nbd. If you're coming from another language with for loops and someone tells you it's a for loop, you might be surprised that you need to use $ and the loop variable comes after the sequence for x in range(10): print(x) forM_ [0..10] $ \x -> putStrLn x

karmakurtisaani 2y ago
I'm convinced the people who came up with Haskell syntax were on some sort of bath salts.
- nequo 2y ago
  The reason it looks the way it does is that forM_ is just a function like any other, not a keyword in a dedicated syntactic construct.
  - karmakurtisaani 2y ago
    Yep, and then there's the $, \ and PutStrLn. As a non-Haskell programmer none of those mean anything to me.
    - nequo 2y ago
      $ is short for “put everything to the right inside parentheses” and \x -> y defines an anonymous function. Why do you expect to understand the syntax of a language you never studied?
      - karmakurtisaani 2y ago
        > $ is short for “put everything to the right inside parentheses” There's, you know, also the actual parentheses that everyone already knows. > Why do you expect to understand the syntax of a language you never studied? Because most languages have a syntax that you can grasp almost immediately, since they conform to a common syntax, rather than invent everything all over again. Then you can focus on the actual features of the language and are not bogged down by syntax.
        nequo 2y ago
        It doesn't take more than two minutes to understand what $ and \x -> y do, and if you start writing out those parentheses, you will also realize why $ is part of idiomatic Haskell.
        tasuki 2y ago
        You know, perhaps Haskell isn't the right language for you. That's fine. Why should it conform to your syntactic preferences?
        eru 2y ago
        > There's, you know, also the actual parentheses that everyone already knows. Those are also available, and are legal syntax in Haskell. > Because most languages have a syntax that you can grasp almost immediately, since they conform to a common syntax, rather than invent everything all over again. I hope you don't count C's `for(something, something; something; something) {` as part of that intuitive bunch? Btw, Haskell didn't re-invent the wheel for most of its syntax: they stuck to the common and already established syntax of the ML family of languages. ML is from 1973. (For comparison, Wikipedia says C is from 1972.)
        karmakurtisaani 2y ago
        > Those are also available, and are legal syntax in Haskell. I don't especially like the idea of making multiple notations for the same thing, to be honest. > I hope you don't count C's `for(something, something; something; something) {` as part of that intuitive bunch? Not my favorite, but at least widely used. I find the style in for example Rust the most easy on the eye. > Btw, Haskell didn't re-invent the wheel for most of its syntax Yeah I actually suspected this was the case.
        eru 2y ago
        > I don't especially like the idea of making multiple notations for the same thing, to be honest. I can appreciate that sentiment, but I'm afraid the designers of Haskell had a different approach there. There often a few different ways to express something. But at least they can often be understood as thin syntactic sugaring of one into the other. It's not like C++ or Perl (or even Ruby with its different types of closures) where you have tons of overlapping ways to express something, and they are all subtly different. > I find the style in for example Rust the most easy on the eye. I'm not sure about easy-on-the-eye, but I find Rust mostly quite bearable, too.
- tome 2y ago
  I think what you're complaining about is not syntax, but lack of syntax. There's nothing syntactially special about this "for loop"! What's the benefit of this then? Firstly, less to learn. If you already understand $ and lambdas, then you understand this structure, and can reuse your knowledge in many places, for example withTempFile "foo" $ \tmpFile -> do <do something with tmpFile> flip fmap myList $ \e -> do <do something with each element i> And you can even create your own constructs. You're not limited to the ones that are built in. (The [0..10] is actually syntax, and I think that's quite unfortunate. `range 0 10` would have been just as good.)
  - eru 2y ago
    > (The [0..10] is actually syntax, and I think that's quite unfortunate. `range 0 10` would have been just as good.) Well, Haskell is in fact flexible enough that you can define that range function. But one reason to make it syntax is that you can define things like [0..], which would be between awkward to impossible to do with a single `range` function in Haskell.
    - tome 2y ago
      Yes, indeed they are both functions, enumFromTo and enumFrom! https://www.stackage.org/haddock/lts-22.22/base-4.18.2.1/Prelude.html#v:enumFrom https://www.stackage.org/haddock/lts-22.22/base-4.18.2.1/Pre... https://www.stackage.org/haddock/lts-22.22/base-4.18.2.1/Prelude.html#v:enumFromTo https://www.stackage.org/haddock/lts-22.22/base-4.18.2.1/Pre...
eru 2y ago
You don't need the $ anymore with `BlockArguments`. But overall, Haskell isn't really any worse here than Rust's for-each; or even C's weird for-loop (where you just have to rote learn what the three parts in the header of the loop do). I agree it's worse than Python's or Rust's vanilla for-loop. I mostly like Python's syntax, I just wish they would make their would declare their indentation syntax to be sugar for a curly brace syntax (like Haskell does), and their would make their statements and blocks give values, like Haskell and Rust do. (Of course, I have some other things I don't like in Python. But her syntax is by-and-large fine.)

karmakurtisaani 2y ago

I'm convinced the people who came up with Haskell syntax were on some sort of bath salts.

nequo 2y ago
The reason it looks the way it does is that forM_ is just a function like any other, not a keyword in a dedicated syntactic construct.
- karmakurtisaani 2y ago
  Yep, and then there's the $, \ and PutStrLn. As a non-Haskell programmer none of those mean anything to me.
  - nequo 2y ago
    $ is short for “put everything to the right inside parentheses” and \x -> y defines an anonymous function. Why do you expect to understand the syntax of a language you never studied?
    - karmakurtisaani 2y ago
      > $ is short for “put everything to the right inside parentheses” There's, you know, also the actual parentheses that everyone already knows. > Why do you expect to understand the syntax of a language you never studied? Because most languages have a syntax that you can grasp almost immediately, since they conform to a common syntax, rather than invent everything all over again. Then you can focus on the actual features of the language and are not bogged down by syntax.
      - nequo 2y ago
        It doesn't take more than two minutes to understand what $ and \x -> y do, and if you start writing out those parentheses, you will also realize why $ is part of idiomatic Haskell.
      - tasuki 2y ago
        You know, perhaps Haskell isn't the right language for you. That's fine. Why should it conform to your syntactic preferences?
      - eru 2y ago
        > There's, you know, also the actual parentheses that everyone already knows. Those are also available, and are legal syntax in Haskell. > Because most languages have a syntax that you can grasp almost immediately, since they conform to a common syntax, rather than invent everything all over again. I hope you don't count C's `for(something, something; something; something) {` as part of that intuitive bunch? Btw, Haskell didn't re-invent the wheel for most of its syntax: they stuck to the common and already established syntax of the ML family of languages. ML is from 1973. (For comparison, Wikipedia says C is from 1972.)
        karmakurtisaani 2y ago
        > Those are also available, and are legal syntax in Haskell. I don't especially like the idea of making multiple notations for the same thing, to be honest. > I hope you don't count C's `for(something, something; something; something) {` as part of that intuitive bunch? Not my favorite, but at least widely used. I find the style in for example Rust the most easy on the eye. > Btw, Haskell didn't re-invent the wheel for most of its syntax Yeah I actually suspected this was the case.
        eru 2y ago
        > I don't especially like the idea of making multiple notations for the same thing, to be honest. I can appreciate that sentiment, but I'm afraid the designers of Haskell had a different approach there. There often a few different ways to express something. But at least they can often be understood as thin syntactic sugaring of one into the other. It's not like C++ or Perl (or even Ruby with its different types of closures) where you have tons of overlapping ways to express something, and they are all subtly different. > I find the style in for example Rust the most easy on the eye. I'm not sure about easy-on-the-eye, but I find Rust mostly quite bearable, too.
tome 2y ago
I think what you're complaining about is not syntax, but lack of syntax. There's nothing syntactially special about this "for loop"! What's the benefit of this then? Firstly, less to learn. If you already understand $ and lambdas, then you understand this structure, and can reuse your knowledge in many places, for example withTempFile "foo" $ \tmpFile -> do <do something with tmpFile> flip fmap myList $ \e -> do <do something with each element i> And you can even create your own constructs. You're not limited to the ones that are built in. (The [0..10] is actually syntax, and I think that's quite unfortunate. `range 0 10` would have been just as good.)
- eru 2y ago
  > (The [0..10] is actually syntax, and I think that's quite unfortunate. `range 0 10` would have been just as good.) Well, Haskell is in fact flexible enough that you can define that range function. But one reason to make it syntax is that you can define things like [0..], which would be between awkward to impossible to do with a single `range` function in Haskell.
  - tome 2y ago
    Yes, indeed they are both functions, enumFromTo and enumFrom! https://www.stackage.org/haddock/lts-22.22/base-4.18.2.1/Prelude.html#v:enumFrom https://www.stackage.org/haddock/lts-22.22/base-4.18.2.1/Pre... https://www.stackage.org/haddock/lts-22.22/base-4.18.2.1/Prelude.html#v:enumFromTo https://www.stackage.org/haddock/lts-22.22/base-4.18.2.1/Pre...

eru 2y ago

You don't need the $ anymore with `BlockArguments`. But overall, Haskell isn't really any worse here than Rust's for-each; or even C's weird for-loop (where you just have to rote learn what the three parts in the header of the loop do). I agree it's worse than Python's or Rust's vanilla for-loop. I mostly like Python's syntax, I just wish they would make their would declare their indentation syntax to be sugar for a curly brace syntax (like Haskell does), and their would make their statements and blocks give values, like Haskell and Rust do. (Of course, I have some other things I don't like in Python. But her syntax is by-and-large fine.)