objective c - My own @{} literals -

as know apple has provided @ literals such classes nsnumber, nsdictionary, nsarray, can create object way, example

nsarray *array = @[obj1, obj2]; 

so wonder, if there way create such literals own classes? example, want write smth.

myclass *object = myclass[value1, value2]; 

and don't want write long parsers :)

@ syntax literals, feature of clang compiler. since compiler feature, no, cannot define own literals.

for more informations compilers literals, please refer clang 3.4 documentation - objective-c literals

edit: also, found this interesting discussion

edit: booranger mentioned @ comments, there exists method create [] accessors (the collection literals way) access custom objects. called object subscripting. using this, can access in custom class myobject[@"somekey"]. read more @ nshipster.

here example implementation of "subcriptable" object. example simplicity, accesses internal dictionary. header:

@interface lksubscriptableobject : nsobject  //  object subscripting - (id)objectforkeyedsubscript:(id <nscopying>)key; - (void)setobject:(id)obj forkeyedsubscript:(id <nscopying>)key;  @end 

implementation:

@implementation lksubscriptableobject {      nsmutabledictionary     *_dictionary; }  - (id)init {     self = [super init];     if (self) {         _dictionary = [nsmutabledictionary dictionary];     }     return self; }  - (id)objectforkeyedsubscript:(id <nscopying>)key {     return _dictionary[key]; }  - (void)setobject:(id)obj forkeyedsubscript:(id <nscopying>)key {     _dictionary[key] = obj; }  @end 

you can access in object using square brackets:

lksubscriptableobject *subsobj = [[lksubscriptableobject alloc] init];  subsobj[@"string"] = @"value 1"; subsobj[@"number"] = @2; subsobj[@"array"] = @[@"arr1", @"arr2", @"arr3"];  nslog(@"string: %@", subsobj[@"string"]); nslog(@"number: %@", subsobj[@"number"]); nslog(@"array: %@", subsobj[@"array"]);