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Show HN: Underscore.js for Objective-C

120 points by robert-boehnke 14y ago

tubbo 14y ago
It's cool that we have an Underscore for Obj-C now, but I'm really excited about this because of the project's opinion that bracket syntax sucks. It's always been a curiosity that a company like Apple, who prides themselves on making great user interfaces can't even get it together to make a programming language that's nice to look at. They seem to care about everyone BUT their own kind these days...
- speg 14y ago
  I just spent the last month learning about iOS (and Obj-C). I didn't find the square brackets that terrible. Explicit is better than implicit after all. It seems like dot notation is best used for properties, but I will reserve judgement until I have more than just a month of casual experience.
  - jparishy 14y ago
    Indeed. Plus I think well-designed Objective-C is some of the prettiest code out there. Though I've been using it for a few years now almost exclusively (for the most part) so maybe I am a bit biased.
- jawngee 14y ago
  You realize objective-c is almost 30 years old and started as preprocessor for C?
- deleted 14y ago
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- deleted 14y ago
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- mcmatterson 14y ago
  I hear this sort of thing frequently, and I've never really understood it. I personally find Objective C wonderfully easy to read & understand, both in terms of interface and implementation. In fact, it's the only language other than Ruby where I frequently catch myself in moments of joy while using it. I find it hard to believe that a compiled, largely static language can feel so flexible in terms of typing and runtime, while at the same time have a strong enough type system that Clang can run the magic it does. I'm not being contradictory here, I'm genuinely curious: what in particular do people find ugly about ObjC. What languages would you appeal to for design hints in light of the needs of Objective C?
- robert-boehnke 14y ago
  I am not saying that named arguments are a bad idea, in fact they are awesome! Often, they make code a lot more readable, consider for example [UIMelon melonWithNumberOfSeeds:10 andPriceInDollars:10]; which is a lot more self explanatory than new Melon(10, 10) That being said, for a lot of common and well known fuctions (including map, filter, reduce), Objective-C tends to be overly verbose. I think everybody is looking forward to the new literals, that will allow you to replace [NSDictionary dictionaryWithObjectsAndKeys:foo, @"foo", bar, @"bar", nil]; with the much more concise @{@"foo": foo, @"bar": bar} Underscore.m tries to achieve something similar. I hope that people will be able see past the - granted, inconventional - syntax to focus on the actual operations done on the data structures. For example: // - (NSDictionary *)transformedDictionary; NSMutableDictionary *result = [NSMutableDictionary dictionary]; [myDict enumerateKeysAndObjectsUsingBlock:^(id key, id obj) { [result setValue:[obj transformedObject] forKey:key]; }]; return result; vs. return _dict(myDict).map(^id (id key, id obj) { return [obj transformedObject]; }) .unwrap;
- batista 14y ago
  >It's cool that we have an Underscore for Obj-C now, but I'm really excited about this because of the project's opinion that bracket syntax sucks. It's always been a curiosity that a company like Apple, who prides themselves on making great user interfaces can't even get it together to make a programming language that's nice to look at. They seem to care about everyone BUT their own kind these days... Yes, and other people have the uninformed idiotic opition that significant whitespace sucks, or that lots of parenthesis a la Lisp suck. Alternative syntaxes do not "suck", nor are superficial features like whitespace, brackets and parenthesis the real essence of a syntax (actually those are not even syntactical, they are lexical, and are handled by the lexer, not the parser). Objective-C is an established language with great features for what it has to do (be dynamic and bridge low level and high level while keeping performance on par with C/C++ when needed). And it has a HUGE API library for both Mobile and Desktop. Not to mention that it has a noble history of being the language on which both the first web browser and the first modern first person shooter were written in.
xsmasher 14y ago
Interesting if you're already used to underscore.js. The more Objective-C way to do this, without the dot syntax and the need for wrapping, is to add categories (sets of extra methods) to the NSArray and NSDictionary classes. The square brackets don't impair chaining in any way - you can still [[[myDict allKeys] filter:filterMethod] invoke: invokeMethod]
- robert-boehnke 14y ago
  I've tried that, but once you pass in blocks as arguments, the whole thing becomes a lot harder to read. I have no clue how to indent [[array filter:^BOOL (id obj) { return [obj passesTest]; }] map:^id (id obj) { return [obj transformedObject] }]; Edit: Also, it's good practice to prefix your categories methods so they don't clash with other category's, so you'd have something like us_map:, us_filter:, reducing readability even further.
  - jawngee 14y ago
    It should be a category on NSObject so it supports anything that supports fast enumeration which could be anything. And the indentation in the above is correct. The way you've implemented it is "anti-conventional" and bad form, imho.
    - natesm 14y ago
      Objective-C is a superset of C, functions can be just that - a function. Especially for higher-order functions like map and filter. Not everything needs to be glued to an object.
      - jawngee 14y ago
        No shit sherlock. That's not what he's doing, he's exposing blocks as properties because he couldn't wrap his head around indentation which is the wrong motivation. Maybe read the source before condescending next time.
cpr 14y ago
If you embrace the Smalltalk roots of Objective-C, you'll be a lot happier, and "all those braces" are completely comprehensible.
- travisjeffery 14y ago
  No, you need to embrace how Objective-C is written today because blocks (and all those braces) are a fundamental part.
  - cpr 14y ago
    I think that's what I was trying to say, but apparently didn't make it clear.
draegtun 14y ago
There are also ports of Underscore.js to Perl & Lua: * http://vti.github.com/underscore-perl/ http://vti.github.com/underscore-perl/ * http://mirven.github.com/underscore.lua/ http://mirven.github.com/underscore.lua/
- iron_ball 14y ago
  And AS3, if you're into that sort of thing (self-plug): https://github.com/amacdougall/underscore.as https://github.com/amacdougall/underscore.as
mullr 14y ago
This brings to mind google's warning re: the use of functional idioms in Java: http://code.google.com/p/guava-libraries/wiki/FunctionalExplained http://code.google.com/p/guava-libraries/wiki/FunctionalExpl... Objective-C blocks make things smoother than Java, but it still feels to me like the language wants you to have a bunch of small objects sending message to each other. (rather than doing function composition) That said, I use underscore.js in nearly all of my browser and node.js code, so I'll certainly consider this when the iPhone train comes back around.
natesm 14y ago
What's the advantage of implementing map/filter as property accessors of a wrapper object instead of just doing: NSArray* map(id<NSFastEnumeration> enumerable, id(^)(id object) block); ? Obviously, you'd still want to have a prefix of some sort for namespacing.
- robert-boehnke 14y ago
  In the case of NSDictionary, Underscore.m's map iterates over objects and keys. Fast Enumeration only iterates over the dictionary's keys, when you probably want the value or both. But I agree, supporting any class that implements NSFastEnumeration would be nice to have.
  - joubert 14y ago
    You may already know this, but you can also enumerate over NSDictionary entries using enumerateKeysAndObjectsUsingBlock: [1] and enumerateKeysAndObjectsWithOptions:usingBlock: [2]. The latter giving you the ability to enumerate in reverse order or spread the enumeration across multiple cores using Grand Central Dispatch. [1] https://developer.apple.com/library/mac/documentation/Cocoa/Reference/Foundation/Classes/nsdictionary_Class/Reference/Reference.html#//apple_ref/occ/instm/NSDictionary/enumerateKeysAndObjectsUsingBlock https://developer.apple.com/library/mac/documentation/Cocoa/...: [2] https://developer.apple.com/library/mac/documentation/Cocoa/Reference/Foundation/Classes/nsdictionary_Class/Reference/Reference.html#//apple_ref/occ/instm/NSDictionary/enumerateKeysAndObjectsWithOptions:usingBlock https://developer.apple.com/library/mac/documentation/Cocoa/...:
    - robert-boehnke 14y ago
      It's exactly what's used internally :)

120 points by robert-boehnke 14y ago

tubbo 14y ago

It's cool that we have an Underscore for Obj-C now, but I'm really excited about this because of the project's opinion that bracket syntax sucks. It's always been a curiosity that a company like Apple, who prides themselves on making great user interfaces can't even get it together to make a programming language that's nice to look at. They seem to care about everyone BUT their own kind these days...

speg 14y ago
I just spent the last month learning about iOS (and Obj-C). I didn't find the square brackets that terrible. Explicit is better than implicit after all. It seems like dot notation is best used for properties, but I will reserve judgement until I have more than just a month of casual experience.
- jparishy 14y ago
  Indeed. Plus I think well-designed Objective-C is some of the prettiest code out there. Though I've been using it for a few years now almost exclusively (for the most part) so maybe I am a bit biased.
jawngee 14y ago
You realize objective-c is almost 30 years old and started as preprocessor for C?
deleted 14y ago
[deleted]
deleted 14y ago
[deleted]
mcmatterson 14y ago
I hear this sort of thing frequently, and I've never really understood it. I personally find Objective C wonderfully easy to read & understand, both in terms of interface and implementation. In fact, it's the only language other than Ruby where I frequently catch myself in moments of joy while using it. I find it hard to believe that a compiled, largely static language can feel so flexible in terms of typing and runtime, while at the same time have a strong enough type system that Clang can run the magic it does. I'm not being contradictory here, I'm genuinely curious: what in particular do people find ugly about ObjC. What languages would you appeal to for design hints in light of the needs of Objective C?
robert-boehnke 14y ago
I am not saying that named arguments are a bad idea, in fact they are awesome! Often, they make code a lot more readable, consider for example [UIMelon melonWithNumberOfSeeds:10 andPriceInDollars:10]; which is a lot more self explanatory than new Melon(10, 10) That being said, for a lot of common and well known fuctions (including map, filter, reduce), Objective-C tends to be overly verbose. I think everybody is looking forward to the new literals, that will allow you to replace [NSDictionary dictionaryWithObjectsAndKeys:foo, @"foo", bar, @"bar", nil]; with the much more concise @{@"foo": foo, @"bar": bar} Underscore.m tries to achieve something similar. I hope that people will be able see past the - granted, inconventional - syntax to focus on the actual operations done on the data structures. For example: // - (NSDictionary *)transformedDictionary; NSMutableDictionary *result = [NSMutableDictionary dictionary]; [myDict enumerateKeysAndObjectsUsingBlock:^(id key, id obj) { [result setValue:[obj transformedObject] forKey:key]; }]; return result; vs. return _dict(myDict).map(^id (id key, id obj) { return [obj transformedObject]; }) .unwrap;
batista 14y ago
>It's cool that we have an Underscore for Obj-C now, but I'm really excited about this because of the project's opinion that bracket syntax sucks. It's always been a curiosity that a company like Apple, who prides themselves on making great user interfaces can't even get it together to make a programming language that's nice to look at. They seem to care about everyone BUT their own kind these days... Yes, and other people have the uninformed idiotic opition that significant whitespace sucks, or that lots of parenthesis a la Lisp suck. Alternative syntaxes do not "suck", nor are superficial features like whitespace, brackets and parenthesis the real essence of a syntax (actually those are not even syntactical, they are lexical, and are handled by the lexer, not the parser). Objective-C is an established language with great features for what it has to do (be dynamic and bridge low level and high level while keeping performance on par with C/C++ when needed). And it has a HUGE API library for both Mobile and Desktop. Not to mention that it has a noble history of being the language on which both the first web browser and the first modern first person shooter were written in.

xsmasher 14y ago

Interesting if you're already used to underscore.js. The more Objective-C way to do this, without the dot syntax and the need for wrapping, is to add categories (sets of extra methods) to the NSArray and NSDictionary classes. The square brackets don't impair chaining in any way - you can still [[[myDict allKeys] filter:filterMethod] invoke: invokeMethod]

robert-boehnke 14y ago
I've tried that, but once you pass in blocks as arguments, the whole thing becomes a lot harder to read. I have no clue how to indent [[array filter:^BOOL (id obj) { return [obj passesTest]; }] map:^id (id obj) { return [obj transformedObject] }]; Edit: Also, it's good practice to prefix your categories methods so they don't clash with other category's, so you'd have something like us_map:, us_filter:, reducing readability even further.
- jawngee 14y ago
  It should be a category on NSObject so it supports anything that supports fast enumeration which could be anything. And the indentation in the above is correct. The way you've implemented it is "anti-conventional" and bad form, imho.
  - natesm 14y ago
    Objective-C is a superset of C, functions can be just that - a function. Especially for higher-order functions like map and filter. Not everything needs to be glued to an object.
    - jawngee 14y ago
      No shit sherlock. That's not what he's doing, he's exposing blocks as properties because he couldn't wrap his head around indentation which is the wrong motivation. Maybe read the source before condescending next time.

cpr 14y ago

If you embrace the Smalltalk roots of Objective-C, you'll be a lot happier, and "all those braces" are completely comprehensible.

travisjeffery 14y ago
No, you need to embrace how Objective-C is written today because blocks (and all those braces) are a fundamental part.
- cpr 14y ago
  I think that's what I was trying to say, but apparently didn't make it clear.

draegtun 14y ago

There are also ports of Underscore.js to Perl & Lua: * http://vti.github.com/underscore-perl/ http://vti.github.com/underscore-perl/ * http://mirven.github.com/underscore.lua/ http://mirven.github.com/underscore.lua/

iron_ball 14y ago
And AS3, if you're into that sort of thing (self-plug): https://github.com/amacdougall/underscore.as https://github.com/amacdougall/underscore.as

mullr 14y ago

This brings to mind google's warning re: the use of functional idioms in Java: http://code.google.com/p/guava-libraries/wiki/FunctionalExplained http://code.google.com/p/guava-libraries/wiki/FunctionalExpl... Objective-C blocks make things smoother than Java, but it still feels to me like the language wants you to have a bunch of small objects sending message to each other. (rather than doing function composition) That said, I use underscore.js in nearly all of my browser and node.js code, so I'll certainly consider this when the iPhone train comes back around.

natesm 14y ago

What's the advantage of implementing map/filter as property accessors of a wrapper object instead of just doing: NSArray* map(id<NSFastEnumeration> enumerable, id(^)(id object) block); ? Obviously, you'd still want to have a prefix of some sort for namespacing.

robert-boehnke 14y ago
In the case of NSDictionary, Underscore.m's map iterates over objects and keys. Fast Enumeration only iterates over the dictionary's keys, when you probably want the value or both. But I agree, supporting any class that implements NSFastEnumeration would be nice to have.
- joubert 14y ago
  You may already know this, but you can also enumerate over NSDictionary entries using enumerateKeysAndObjectsUsingBlock: [1] and enumerateKeysAndObjectsWithOptions:usingBlock: [2]. The latter giving you the ability to enumerate in reverse order or spread the enumeration across multiple cores using Grand Central Dispatch. [1] https://developer.apple.com/library/mac/documentation/Cocoa/Reference/Foundation/Classes/nsdictionary_Class/Reference/Reference.html#//apple_ref/occ/instm/NSDictionary/enumerateKeysAndObjectsUsingBlock https://developer.apple.com/library/mac/documentation/Cocoa/...: [2] https://developer.apple.com/library/mac/documentation/Cocoa/Reference/Foundation/Classes/nsdictionary_Class/Reference/Reference.html#//apple_ref/occ/instm/NSDictionary/enumerateKeysAndObjectsWithOptions:usingBlock https://developer.apple.com/library/mac/documentation/Cocoa/...:
  - robert-boehnke 14y ago
    It's exactly what's used internally :)