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Currying

wiki.haskell.org

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Re: Currying

#21

Post by yen223 »

IshKebab wrote: post #10

I always thought currying was a bad idea. It makes the code way less readable: * more difficult to distinguish arguments and return values (there's a reason most languages have distinct syntax for them) * it encourages you to put your arguments in an order that might not be the most logical And on top of that it only works for the last argument(s). Feels like a lot of disadvantages to allow an overly clever trick tha…

I much prefer partial application. It just makes more intuitive sense - you take a function with many arguments, "fix" some of those arguments, and get a new function out. No need to mess with argument ordering, or all that.

It's a shame the only language that did partial application well is, weirdly, Python.

Re: Currying

#22

Post by zarzavat »

worddepress wrote: post #9
solardev wrote: post #2

In my entire life as a programmer, this is the one thing that I've found most confusing. Our old codebase used a lot of curried Ramda functions and nobody on the team could read any of it. We spent a week ripping every single instance of it out and replaced it with regular lodash and never looked back and never had an issue with it again. After like ten or fifteen hours of trying to understand what currying is, I sti…

In Haskell it is easy. If you "forget" the last argument to a function, you get returned a function where you can provide that later on. A bit like saying "you can fill this in later". That is a "curried" function. Example add 1 2 // add is curried, you can use it like this, the "normal" way, returns 3 p = add 1 // since add is curried I can also provide just the first argument p 2 // and then apply the last argument…

It’s worth noting that even in Haskell, overuse of the so called point-free style is disliked for much the same reasons:

https://wiki.haskell.org/Pointfree

There is a sliding scale and even at the Haskellers have a limit of how much point-free they can take.

In JavaScript use of the style is problematic in another way: unlike Haskell in JS the length of the argument list is variable, which means that if someone adds another argument to either the caller or callee it can break the code in subtle and unexpected ways.

For this reason it’s good practice to always wrap functions being passed as arguments to another function in a lambda expression.

i.e instead of writing: g(f), you should usually write: g(x => f(x)) unless you have good reason to believe that g(f) is safe. This makes it difficult to use point-free style at all in JS.

For example arr.map(f) is generally unsafe in JS because if `f` adds an extra default argument of type number then your code will break and even TypeScript won’t let you know.

Re: Currying

#23

Post by kccqzy »

solardev wrote: post #2

In my entire life as a programmer, this is the one thing that I've found most confusing. Our old codebase used a lot of curried Ramda functions and nobody on the team could read any of it. We spent a week ripping every single instance of it out and replaced it with regular lodash and never looked back and never had an issue with it again. After like ten or fifteen hours of trying to understand what currying is, I sti…

> After like ten or fifteen hours of trying to understand what currying is

I have doubts on whether this is a sincere attempt at understanding the concept. The linked wiki page is like a five minute read and that's enough to understand the concept at a user's level.

What I suspect is that something else is tripping you up and causing code readability issues; but since you didn't know what currying is you incorrectly ascribed currying as the problem.

Re: Currying

#24

Post by [deleted] »

solardev wrote: post #2

In my entire life as a programmer, this is the one thing that I've found most confusing. Our old codebase used a lot of curried Ramda functions and nobody on the team could read any of it. We spent a week ripping every single instance of it out and replaced it with regular lodash and never looked back and never had an issue with it again. After like ten or fifteen hours of trying to understand what currying is, I sti…

[deleted]

Re: Currying

#25

Post by inopinatus »

solardev wrote: post #15
082349872349872 wrote: post #12

Earlier quoted context omitted.

Function arguments work like the power rule for exponents in elementary school math: f a b = g(a,b) = f' b a (x^2)^3 = x^(2*3) = (x^3)^2

You must've gone to a pretty kick ass elementary school. In mine, we'd play Connect Four and make paintings out of fake hieroglyphs...

When I were a lad, elementary school meant four hours of beatings in a muddy field, and we were glad of it

Re: Currying

#26

Post by bPspGiJT8Y »

yen223 wrote: post #21
IshKebab wrote: post #10

I always thought currying was a bad idea. It makes the code way less readable: * more difficult to distinguish arguments and return values (there's a reason most languages have distinct syntax for them) * it encourages you to put your arguments in an order that might not be the most logical And on top of that it only works for the last argument(s). Feels like a lot of disadvantages to allow an overly clever trick tha…

I much prefer partial application. It just makes more intuitive sense - you take a function with many arguments, "fix" some of those arguments, and get a new function out. No need to mess with argument ordering, or all that. It's a shame the only language that did partial application well is, weirdly, Python.

In Gleam it also seems to be done well: https://tour.gleam.run/functions/function-captures/

Re: Currying

#27

Post by threatofrain »

kccqzy wrote: post #23
solardev wrote: post #2

In my entire life as a programmer, this is the one thing that I've found most confusing. Our old codebase used a lot of curried Ramda functions and nobody on the team could read any of it. We spent a week ripping every single instance of it out and replaced it with regular lodash and never looked back and never had an issue with it again. After like ten or fifteen hours of trying to understand what currying is, I sti…

> After like ten or fifteen hours of trying to understand what currying is I have doubts on whether this is a sincere attempt at understanding the concept. The linked wiki page is like a five minute read and that's enough to understand the concept at a user's level. What I suspect is that something else is tripping you up and causing code readability issues; but since you didn't know what currying is you incorrectly…

Yeah 10-15 hours is kinda crazy for an introductory topic.

Re: Currying

#28

Post by 082349872349872 »

inopinatus wrote: post #25
solardev wrote: post #15

Earlier quoted context omitted.

You must've gone to a pretty kick ass elementary school. In mine, we'd play Connect Four and make paintings out of fake hieroglyphs...

When I were a lad, elementary school meant four hours of beatings in a muddy field, and we were glad of it

On that note, I found Orwell's posthumously-published Such, Such Were the Joys (about his boarding school days) suggests the inspirations behind large swaths of 1984.

Re: Currying

#29

Post by MarkSweep »

solardev wrote: post #14
worddepress wrote: post #7

Earlier quoted context omitted.

Almost as if an astronaut can come, do their thing in a whirlwind and leave for another company 2 years later, while the remaining plebs have to figure it all out.

Yeah, a lot of the codebase was like that. Some lone wolf mad genius that occasionally left pieces of pure brilliance behind, but more often than not, just wrote code that was incredibly idiosyncratic and unnecessarily reinvented. Like he'd spend several files making a color gradient visualization system with his own scales, with an enthusiastic but limited understanding of color theory, that ended up producing mostl…

> But then again, he's a multi millionaire now and I'm a rando nobody living paycheck to paycheck, so I'm in no place to judge lol.

If he had not made such a big mess, you might not be getting this paycheck to clean it up. I think they call this “creating scope for other people” at big companies, real staff engineer stuff. =)

Re: Currying

#30

Post by whilenot-dev »

skybrian wrote: post #11

When you pass some arguments to a constructor and then later, you pass some more arguments to a method, that’s equivalent to currying. Method calls are easier to read and work better with autocomplete.

I think you confuse currying with partial application.
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