Subjective-Script makes Objective-C more scripty!
Note: Subjective-Script requires ARC to be enabled on your Objective-C project.
My language of preference is CoffeeScript and whenever I develop in Objective-C, I find myself often having to look up [NSSomething reallyLongFunctionName:YES withAVerboseParameterName:YES and:[NSSomethingElse whichAddsMoreBrackets]] and it isn't very enjoyable or speedy!
While I was porting a test for _.m from the original Underscore.js that was easy to read:
var people = [{name : 'curly', age : 50}, {name : 'moe', age : 30}];
people = _.sortBy(people, function(person){ return person.age; });
equal(_.pluck(people, 'name').join(', '), 'moe, curly', 'stooges sorted by age');It looked like this in Objective-C:
NSArray *people = [NSArray arrayWithObjects:
[NSDictionary dictionaryWithObjectsAndKeys: @"moe", @"name", [NSNumber numberWithInt:30], @"age", nil],
[NSDictionary dictionaryWithObjectsAndKeys: @"curly", @"name", [NSNumber numberWithInt:50], @"age", nil],
nil];
STAssertEqualObjects([_.pluck(people, @"name") componentsJoinedByString:@", "],
@"moe, curly",
@"stooges sorted by age");
The keys were in the wrong order, there was too much typing involved, and it became unreadable. So I wrote Subjective-Script and ported QUnit.m to end up with this:
A* people = AO(OKV({@"name", @"curly"}, {@"age", N.I(50)}), OKV({@"name", @"moe"}, {@"age", N.I(30)}));
people = _.sortBy(people, ^(O* person){ return person.get(@"age"); });
equal(_.pluck(people, @"name").join(@", "), @"moe, curly", @"stooges sorted by age");
Much better! And best of all, I can reuse my knowledge of JavaScript for function names so I can stop looking things up and get stuff done!
While JavaScript allows flexibility in variable types, Objective-C requires explicit variable types. To try to keep it brief, I tried to condense types down to the shortest name possible:
typedef BOOL B;
typedef NSInteger I;
typedef NSUInteger UI;
typedef float F;
typedef double D;
typedef id KV[2]; // key-value pair
#define NSO NSObject
#define A NSMutableArray
#define NSA NSArray
#define O NSMutableDictionary
#define NSD NSDictionary
#define S NSMutableString
#define NSS NSString
#define Date NSDate
#define N NSNumber
#define E NSException
and I tried to shorten NSNumbers, too, using the above abbreviations (B, I, UI, F, D):
N* value = N.B(true);
equal(value.B, true, @"YES it is!")
I tried many different ways, but this seemed to be easy-to-read and brief (with key-value pair matching checked by the compiler):
A* arrayOfInts = AI(1, 2, 3);
A* arrayOfObjects = AO(N.I(1), N.F(2.0), @"hello", nil, O.new);
I intValue = arrayOfInts.getAt(0).I; // or: intValue = arrayOfInts.get(@"1").I;
arrayOfInts.setAt(0, N.I(intValue+1)); // or: arrayOfInts.set(@"1", N.I(intValue+1));
O* obj = OKV({@"int", N.I(1)}, {@"float", N.F(2.0)}, {@"string", @"hello"}, {@"nil", nil}, {@"dictionary", O.new});
intValue = obj.get(@"int").I;
obj.set(@"int", N.I(intValue+1));
would be equivalent to the following Javascript:
var arrayOfInts = [1, 2, 3];
var arrayOfObjects = [1, 2.0, 'hello', null, {}];
var intValue = arrayOfInts[0];
arrayOfInts[0] = intValue+1;
var obj = {int: 1, float: 2.0, string: 'hello', nil: null, dictionary:{}};
intValue = obj.int; // or: intValue = obj['int'];
obj.int = intValue+1; // or: obj['int'] = intValue+1;
and if you are interested, Objective-C may make the syntax even lighter using Objective-C literals in the future:
NSA* arrayOfInts = @[@1, @2, @3];
NSA* arrayOfObjects = @[@1, @2.0, @"hello", NSNull.null, @{}];
NSD* obj = @{@int: @1, @float: @2.0, @string: @"hello", @nil: NSNull.null, @dictionary:@{}};
To be able to reuse my JavaScript knowledge and not have to look through StackOverflow for really basic things that are hard to remember in Objective-C, I've ported some common JavaScript functions.
N.I(1).instanceof(N.class);
// true
(A.new).instanceof(NSA.class);
// true
N.B(true).toString();
// @"true"
OKV({@"key1", @"value1"}).toString();
// @"[object Object]"
AO(AI(1,2,3),N.F(4.5),OKV({@"five", @"5"})).toString();
// @"[[1,2,3],4.5,[object Object]]
AI(1,2,3).length;
// 3
AI(1,2,3).hasOwnProperty(@"2");
// true
AI(1,2,3).get(@"2");
// N.I(3)
AI(1,2,3).concat(AI(1,2,4);
// [1,2,3,1,2,4]
AO(@"Banana", @"Orange", @"Lemon", @"Apple", @"Mango").slice(-3,-1);
// [Lemon,Apple]
AI(1,2,3).reverse();
// [3,2,1]
AO(N.I(1),AI(2,3)).flatten(true);
// [1,2,3]
AI(1,2,3).pop();
// N.I(3)
AI(1,2,3).push(N.I(4)).push(@"out the door");
// [1,2,3,4,out the door]
AI(3,2,1,2).sort(nil);
// [1,2,2,3]
AO(@"Banana", @"Orange", @"Apple", @"Lemon").splice(2,1, @"Kiwi", @"Mango", nil);
// [Banana,Orange,Kiwi,Mango,Lemon]
AI(3,4,5).unshift(N.I(1),N.I(2),nil);
// [1,2,3,4,5]
AI(1,2,3,4,5).shift();
// [2,3,4,5]
OKV({@"int", N.I(1)}, {@"float", N.F(2.0)}).hasOwnProperty(@"int");
// true
OKV({@"int", N.I(1)}, {@"float", N.F(2.0)}).delete_(@"int").hasOwnProperty(@"int");
// false
@"int".in(OKV({@"int", N.I(1)}, {@"float", N.F(2.0)}));
// true
delete obj.key or delete obj['key'] -> obj.delete_(@"key") -> what is the delete resevered word for..can it be used?
@"hello world!".split(@" ")
// [@"hello", @"world!"]
@"hello world!".split(@"");
// [@"h", @"e", @"l", @"l", @"o", @"w", @"o", @"r", @"l", @"d", @"!"]
@"hello".add(@"world!");
// @"hello world!"
S* message = S.newS(@"hello"); message.append(@" world!");
// message == @"hello world!"
SS.stringify(Date.newYMD_JS(2012, 7, 31));
// @"2012-08-30T15:00:00.000Z"
O* obj = OKV({@"mirror", ^(NSS* string){return string.add(@" mirror"); }});
@"mirror".call(obj, @"hello", nil);
// @"hello mirror"
@"mirror".apply(obj, AO(@"hello"));
// @"hello mirror"
There are a few utilities on the Subjective-Script base object rather than making them global as in JavaScript.
SS.stringify(AO(N.I(1), N.F(2.0), N.F(3.1), @"hello", nil, O.new));
// @"[1,2,3.1,\"hello\",null,{}]"
SS.parseInt(@"123");
// N.I(123)
SS.typeof_(N.B(true));
// @"boolean"
SS.typeof_(@"string");
// @"string"
SS.typeof_(Date.new);
// @"object"
__block BOOL called1 = false;
SSTimeout* timeout1 = SS.setTimeout(^{ called1 = true; }, NSEC_PER_SEC*1);
SS.clearTimeout(timeout1);
// not called
__block BOOL called2 = false;
SS.setTimeout(^{ called2 = true; }, NSEC_PER_SEC*2);
// called
You can also easily add named properties on your own objects:
@interface MyObject : O
@property (strong) NSS* name;
@end
@implementation MyObject : O
@dynamic name;
IMPLEMENT_NAMED_PROPERTIES
@end
MyObject* obj = MyObject.new;
obj.name = @"Steve";
// they call me Steve
So you can write the initial example like:
@interface Stooge : O
@property (strong) NSS* name;
@property (strong) N* age;
@end
@implementation Stooge
@dynamic name, age;
IMPLEMENT_NAMED_PROPERTIES
@end
A* people = AO(OTKV(Stooge, {@"name", @"curly"}, {@"age", N.I(50)}), OTKV(Stooge, {@"name", @"moe"}, {@"age", N.I(30)}));
people = _.sortBy(people, ^(Stooge* person){ return person.age; }); // no get(@"age") required
equal(_.pluck(people, @"name").join(@", "), @"moe, curly", @"stooges sorted by age");
To run the example project; clone the repo, and run pod install from the Project directory first.
SubjectiveScript.m is available through CocoaPods, to install it simply add the following line to your Podfile:
pod "SubjectiveScript.m"
Kevin Malakoff, [email protected]
SubjectiveScript.m is available under the MIT license. See the LICENSE file for more info.
Currently, this is still early days and there is a lot to add and test. Please help out!
If there is anything else you would like added, just implement it in a good place, write the appropriate tests, and submit a pull request on GitHub.
Also, feel free to submit your favorite features from other languages as long as they are easy to remember and help speed up development!