I love the shorthand handling of string literals in Objective C with the @"string"
notation. Is there any way to get similar behavio开发者_运维问答r with NSNumber
s? I deal with numbers more and it's so tedious having [NSNumber numberWithWhatever:]
calls everywhere. Even creating a macro would work, but my knowledge of how best to do that is limited.
Since nobody has mentioned this... If you need to wrap a value in an NSNumber, the NSNumber literal syntax is as follows.
int val = 13;
NSNumber *numVal = @(val);
As of Clang v3.1 you can now use Objective-C literals.
NSNumber *fortyTwo = @42; // equivalent to [NSNumber numberWithInt:42]
NSNumber *fortyTwoUnsigned = @42U; // equivalent to [NSNumber numberWithUnsignedInt:42U]
NSNumber *fortyTwoLong = @42L; // equivalent to [NSNumber numberWithLong:42L]
NSNumber *fortyTwoLongLong = @42LL; // equivalent to [NSNumber numberWithLongLong:42LL]
So, answering your specific question:
[Tyler setArms:[[[NSNumber alloc] initWithInt:1] autorelease]];
Can now be written as:
[Tyler setArms:@1];
There are also literals for arrays and dictionaries, but they are beyond the scope of this question.
To take advantage of literals in Xcode you'll need at least version 4.4 -- this comes with Apple's LLVM 4.0 compiler.
I'm using a macro like
#define N(x) [NSNumber numberWithInt: x]
wich leads to code like
[N(123) intValue];
update:
One should be aware of the CPU and memory consumption of such a macro. While the @"…"
strings are static compiler generated strings of the constant string class (depends on foundation maybe NSConstantString
in Cocoa?) the macros create code which is evaluated at runtime and therefore create a new object every time they are called.
Xcode 4.4 has introduced the Clang features that rjstelling mentioned for literals for NSNumber
, NSArray
and NSDictionary
. The syntax is simple:
//Number literal
NSNumber *pi = @3.14;
//Array literal
NSArray *primes = @[ @2, @3, @5, @7, @11 ]; //No nil terminator needed
//Dictionary literal
NSDictionary *dict = @{
@"key1": @42,
@"key2": @"Another key",
@3: @"A NSNumber key"
}; //No nil terminator, stored in "key:value," format
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