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Show HN: Dollar and Cent – A functional tool belt for Swift

55 points by agp2572 12y ago

agp2572 12y ago
Dollar is a Swift library that provides useful functional programming helper methods without extending any built in objects. It is similar to Lo-Dash or Underscore in Javascript. Cent is a library that extends certain Swift object types using the extension feature like ActiceSupport in ruby and gives its two cents to Swift language.
randomguy7788 12y ago
its unfortunate that it repeats the same mistakes that underscore and lodash does (imo) and makes it very hard to do composition (data comes in first instead of the predicate/function)
- ankurpatel 12y ago
  The plan is to implement extensions as well.
  - randomguy7788 12y ago
    that is awesome to hear!
MrGando 12y ago
Hate this stuff, Swift != Javascript.
- ankurpatel 12y ago
  Haters gonna hate :) But really functions are first class citizens in Swift and it is designed to be a hybrid between OO and functional programming language. It doesn't implement some of the common helper functions like pluck, difference, intersection, etc. This is where this or another library comes in.
- jaxytee 12y ago
  A lot of these functions transcend javascript, and are a product the functional world.
- Nekorosu 12y ago
  It's not Objective C also. Move on. The new world awaits. Though dollar swift is a little bit cheesy for my taste.
  - MrGando 12y ago
    A little bit cheesy? People should file Apple radars if they there's functionality missing in a Beta Language. Not just try to catch attention and stars in Github with useless (at least in this stage) projects. PS: I insist, an expressive language like Swift doesn't need '$.' Cheers.
    - ankurpatel 12y ago
      MrGando I felt '$.' was needed to avoid less typing for developers while at the same time introducing a namespace that doesn't conflict with anything in the developers project. Namespace is needed to avoid conflicts with function names as those same functions could be defined inside another function or class causing compiler errors when building. Before calling this project useless please consider the alternative which is none. Apple will take its time even if you tell them to implement these. You can either implement these helper methods yourself or you can use this or another library. Out of the thousands of people who saw this and liked it I expect few haters like you cause "If people don't hate then it won't be right"
      - Nekorosu 12y ago
        I have a feeling MRGando means the library doesn't look idiomatic enough. Though this meaning is lost behind the tone of the message.
    - Nekorosu 12y ago
      Well... actually you have a good point about some projects existing mostly (if not only) for self-promotion purpose. Talking about Swift's expressiveness. After skimming through Apple's Swift book I tend to agree with you. I misunderstood your first comment having a thought you wanted Swift code to be more like Objective C.
GuiA 12y ago
first Returns the first element in the array and terminated the chain second Returns the second element in the array and terminated the chain third Returns the third element in the array and terminated the chain fourth Returns the fourth element in the array and terminated the chain fifth Returns the fifth element in the array and terminated the chain sixth Returns the sixth element in the array and terminated the chain seventh Returns the seventh element in the array and terminated the chain eighth Returns the eighth element in the array and terminated the chain ninth Returns the ninth element in the array and terminated the chain tenth Returns the tenth element in the array and terminated the chain ... is this a joke?
- agp2572 12y ago
  Is Rail's ActiveSupport a joke? https://github.com/rails/rails/blob/a31277011814b7bdb6be41a807e14d6bf2852620/activesupport/lib/active_support/core_ext/array/access.rb#L57 https://github.com/rails/rails/blob/a31277011814b7bdb6be41a8...
  - p4lindromica 12y ago
    I think the specific example you gave actually is a joke. http://www.quora.com/Why-is-Array-forty_two-called-the-reddit-in-Ruby-on-Rails http://www.quora.com/Why-is-Array-forty_two-called-the-reddi...
    - ankurpatel 12y ago
      Yes it is :)
- Karunamon 12y ago
  Not really, it's just a way to make your code more expressive in a different way, I can see it helping in some cases since arrays are zero-indexed. arr.first is more immediately expressive to me than arr[0] - but this is a matter of opinion :)
- sanderjd 12y ago
  It's pretty interesting to compare the extent to which different libraries take this idea. I think tenth is the furthest I've seen. I find first and last useful frequently, but I think the furthest of these ordinals I've ever used in real code was second or maybe third.
vilya 12y ago
I don't understand why every result is stored into the same class-level variable. What's the aim behind that? It just seems like it would introduce unexpected behaviour without any gain, but I don't really know swift yet so maybe there's something I'm missing?
- agp2572 12y ago
  Static methods are defined using class keywork.
  - vilya 12y ago
    Ah I see I read the code too quickly - I didn't notice that not all of the functions were static. Thanks, I've learnt a bit about Swift by reading your code.
lsdafjklsd 12y ago
Not so much functional as just useful methods for working with arrays / maps. It would be functional to include a compose method... also currying is going to be painful because of how the arguments are structured (data first).

55 points by agp2572 12y ago

Dollar is a Swift library that provides useful functional programming helper methods without extending any built in objects. It is similar to Lo-Dash or Underscore in Javascript. Cent is a library that extends certain Swift object types using the extension feature like ActiceSupport in ruby and gives its two cents to Swift language.

randomguy7788 12y ago

its unfortunate that it repeats the same mistakes that underscore and lodash does (imo) and makes it very hard to do composition (data comes in first instead of the predicate/function)

ankurpatel 12y ago
The plan is to implement extensions as well.
- randomguy7788 12y ago
  that is awesome to hear!

MrGando 12y ago

Hate this stuff, Swift != Javascript.

ankurpatel 12y ago
Haters gonna hate :) But really functions are first class citizens in Swift and it is designed to be a hybrid between OO and functional programming language. It doesn't implement some of the common helper functions like pluck, difference, intersection, etc. This is where this or another library comes in.
jaxytee 12y ago
A lot of these functions transcend javascript, and are a product the functional world.
Nekorosu 12y ago
It's not Objective C also. Move on. The new world awaits. Though dollar swift is a little bit cheesy for my taste.
- MrGando 12y ago
  A little bit cheesy? People should file Apple radars if they there's functionality missing in a Beta Language. Not just try to catch attention and stars in Github with useless (at least in this stage) projects. PS: I insist, an expressive language like Swift doesn't need '$.' Cheers.
  - ankurpatel 12y ago
    MrGando I felt '$.' was needed to avoid less typing for developers while at the same time introducing a namespace that doesn't conflict with anything in the developers project. Namespace is needed to avoid conflicts with function names as those same functions could be defined inside another function or class causing compiler errors when building. Before calling this project useless please consider the alternative which is none. Apple will take its time even if you tell them to implement these. You can either implement these helper methods yourself or you can use this or another library. Out of the thousands of people who saw this and liked it I expect few haters like you cause "If people don't hate then it won't be right"
    - Nekorosu 12y ago
      I have a feeling MRGando means the library doesn't look idiomatic enough. Though this meaning is lost behind the tone of the message.
  - Nekorosu 12y ago
    Well... actually you have a good point about some projects existing mostly (if not only) for self-promotion purpose. Talking about Swift's expressiveness. After skimming through Apple's Swift book I tend to agree with you. I misunderstood your first comment having a thought you wanted Swift code to be more like Objective C.

GuiA 12y ago

first Returns the first element in the array and terminated the chain second Returns the second element in the array and terminated the chain third Returns the third element in the array and terminated the chain fourth Returns the fourth element in the array and terminated the chain fifth Returns the fifth element in the array and terminated the chain sixth Returns the sixth element in the array and terminated the chain seventh Returns the seventh element in the array and terminated the chain eighth Returns the eighth element in the array and terminated the chain ninth Returns the ninth element in the array and terminated the chain tenth Returns the tenth element in the array and terminated the chain ... is this a joke?

agp2572 12y ago
Is Rail's ActiveSupport a joke? https://github.com/rails/rails/blob/a31277011814b7bdb6be41a807e14d6bf2852620/activesupport/lib/active_support/core_ext/array/access.rb#L57 https://github.com/rails/rails/blob/a31277011814b7bdb6be41a8...
- p4lindromica 12y ago
  I think the specific example you gave actually is a joke. http://www.quora.com/Why-is-Array-forty_two-called-the-reddit-in-Ruby-on-Rails http://www.quora.com/Why-is-Array-forty_two-called-the-reddi...
  - ankurpatel 12y ago
    Yes it is :)
Karunamon 12y ago
Not really, it's just a way to make your code more expressive in a different way, I can see it helping in some cases since arrays are zero-indexed. arr.first is more immediately expressive to me than arr[0] - but this is a matter of opinion :)
sanderjd 12y ago
It's pretty interesting to compare the extent to which different libraries take this idea. I think tenth is the furthest I've seen. I find first and last useful frequently, but I think the furthest of these ordinals I've ever used in real code was second or maybe third.

vilya 12y ago

I don't understand why every result is stored into the same class-level variable. What's the aim behind that? It just seems like it would introduce unexpected behaviour without any gain, but I don't really know swift yet so maybe there's something I'm missing?

agp2572 12y ago
Static methods are defined using class keywork.
- vilya 12y ago
  Ah I see I read the code too quickly - I didn't notice that not all of the functions were static. Thanks, I've learnt a bit about Swift by reading your code.

lsdafjklsd 12y ago

Not so much functional as just useful methods for working with arrays / maps. It would be functional to include a compose method... also currying is going to be painful because of how the arguments are structured (data first).