How can I know that clang::NamedDecl contains identifier of function?
I have pointer on clang::NamedDecl.
You can use isa or dyn_cast, e.g.
if (FunctionDecl *F = dyn_cast<FunctionDecl>(myNamedDecl)) {
// use F
}
Related
I want to find declarations that has '&'; such as int *m = &b, then do something translations on such declarations.
Now, I use ASTMatcher varDecl() to find all VarDecl, and use declVar->getType().getTypePtr().getAs<clang::PointerType>() to get the pointer declartions.
What functions can I use to find such 'm = &b' declarations next?
Matcher.addMatcher(varDecl(unless(parmVarDecl())).bind("varDecl"), &VarD);
virtual void run(const MatchFinder::MatchResult &Result) {
ASTContext *Context = Result.Context;
SourceManager &sourceManager_ = Context->getSourceManager();
const VarDecl *declVar = Result.Nodes.getNodeAs<VarDecl>("varDecl");
const clang::Type *type = declVar -> getType().getTypePtr();
const clang::PointerType *pointer_type = type -> getAs
<clang::PointerType>();
if(pointer_type != NULL){
// what functions can I use to find m=&b
}
}
& is the unary operator inside of the variable declaration initialization. This makes the following matcher:
varDecl(unless(parmVarDecl()), hasInitializer(unaryOperator(hasOperatorName("&"))))
NOTE: you can utilize a useful little tool by clang team: clang-query. It helps you to check your matchers interactively.
Have a happy hacking with clang!
In objective-c I am passing NSMutableDictionary to function and modifying it inside function it returns modified mutable dictionary :
NSMutableDictionary *obj2 = [[NSMutableDictionary alloc]initWithObjectsAndKeys:#"hello",#"fname",nil];
[self callerDictionary:obj2];
NSLog(#"%#",obj2[#"fname"]);//printing "Hi"
-(void)callerDictionary:(NSMutableDictionary*)obj
{
obj[#"fname"] = #"Hi";
}
Technically, Objective C always passes parameter by value, as does C, but practically when you pass an object you need to pass a pointer. While this pointer is passed by value, the semantics of Objective-C give the same effect as if you had passed an object reference; if you modify the objected that is pointed to by the pointer then you are modifying the same object instance that is pointed to in the calling context. The common terminology used in Objective C programming is "object reference" even though it is really a pointer value.
You can see from the * in the method signature that it is a pointer (or object reference in the common usage). If you are passing an intrinsic type, such as an int then it is passed by value unless you explicitly declare the method as requiring a reference:
For example:
-(void) someFunction:(int *)intPointer {
*intPointer = 5;
}
would be called as
int someInteger = 0;
[self someFunction: &someInteger];
// someInteger is now 5
The distinction between a pointer value and a true object reference can be seen in comparison to Swift which uses true references;
If I have
-(void)someFunction:(NSString *)someString {
int length = [someString length];
}
and then do
NSMutableArray *array = [NSMutableArray new];
[someFunction: (NSString *)array];
I will get a runtime exception since array doesn't have a length method, but the compiler can't confirm the type I am passing since it is a pointer.
If I attempted the equivalent in Swift then I will get a compile time error since it knows that the type coercion will always fail
All objects in Objective C passed by reference.
All C types such as NSUInteger, double etc. passed by value
C and Objective-C always pass parameters by value. Objective-C objects are always accessed through a reference (i.e. a pointer). There is a difference between a variable type (int, pointer, etc.) and the way variables are passed as function parameters. The use of the term reference in both scenarios can cause confusion.
by-value:
void f(int a) {
a = 14;
}
int a = 5;
NSLog(#"%d", a); // prints: 5
f(a);
NSLog(#"%d", a); // prints: 5
The value 5 is printed both times because the function f() is given a copy of the value of a, which is 5. The variable referenced within the function is not the same variable that was passed in; it is a copy.
In C++, you can have functions that take parameters by reference.
by-reference:
void f(int &a) {
a = 14;
}
int a = 5;
NSLog(#"%d", a); // prints: 5
f(a);
NSLog(#"%d", a); // prints: 14
Note the & in the function signature. In C++ (but not C, nor Objective-C), this means that the parameter is passed by reference. What this means is that a reference (pointer) to a is passed to the function. Within the function, the a variable is implicitly dereferenced (remember, it's really a pointer, but you don't treat it as one), and the original a variable declared outside the function is changed.
In C and Objective-C, passing a pointer to a function is functionally equivalent to using a reference parameter in C++. This is because a copy of the address is given to the function (remember, the parameter is still passed by value), and that address points to the same object instance that the original pointer does. The reason you don't see any explicit pointer dereferencing within the function (similar to the C++ reference) is because Objective-C syntax for object access always implicitly dereferences -- being within a function doesn't change this behavior.
I i'm getting the error "Implicit conversion of 'int' to 'id' is disallowed with ARC" at the line marked with "faulty line". I guess it have something to do with that i'm checking for an integer in an array, that contains objects instead of integers.
#import "RandomGenerator.h"
#implementation RandomGenerator
NSMutableArray *drawnNumbers;
-(int) randomNumber:(int)upperNumber {
return arc4random_uniform(upperNumber);
}
-(NSMutableArray*) lotteryNumbers :(int)withMaximumDrawnNumbers :(int)andHighestNumber {
for (int i = 1; i <= withMaximumDrawnNumbers; i++)
{
int drawnNumber = [self randomNumber:andHighestNumber];
if ([drawnNumbers containsObject:drawnNumber]) { //faulty line
//foo
}
}
return drawnNumbers;
}
#end
NSArrays can only contain objective-c objects. So actually the method containsObject: is expecting an object, not an int or any other primitive type.
If you want to store number inside an NSArray you should pack them into NSNumber objects.
NSNumber *someNumber = [NSNumber numberWithInt:3];
In your case, if we assume that drawnNumbers is already an array of NSNumbers, you should change the randomNumber: generation to:
-(NSNumber*) randomNumber:(int)upperNumber {
return [NSNumber numberWithInt:arc4random_uniform(upperNumber)];
}
And then when picking it up on the lotteryNumbers method, you should:
NSNumber *drawnNumber = [self randomNumber:andHighestNumber];
Another note would go for the method you defined for lotteryNumbers. You used a really strange name for it, I think you misunderstood how the method naming works in objective-c. You were probably looking for something more like:
-(NSMutableArray*) lotteryNumbersWithMaximumDrawnNumbers:(int)maximumDrawnNumbers andHighestNumber:(int)highestNumber;
Late edit:
Objective-C now allows a way more compact syntax for creating NSNumbers. You can do it like:
NSNumber *someNumber = #(3);
And your method could be rewritten as:
-(NSNumber*) randomNumber:(int)upperNumber {
return #(arc4random_uniform(upperNumber));
}
You are using an int where an object (presumably NSNumber) is expected. So convert before use:
if ([drawnNumbers containsObject:#( drawnNumber )])
I would like to know if they have an equivalent in Objective C of the JAVA's methode "BeanUtils.CopyProperties(bean1, Bean2);" ?
Or other solution, i would like to cast motherObject to childObject :
#interface motherBean : NSObject{ ...}
#interface childBean : motherBean { ...}
motherBean m = [motherBean new];
childBean f = m;
With the first tests it's work but I have a warning : "incompatible pointer types returning ...";
I use WSDL2Objc and it generate bean, and the name of it can change between 2 generation :-/
I prefere to work with the child and just change the name in her definition
Thanks
Anthony
Take a look at commons-beanutils package. It has lots of property method for you to copy stuff. In particular:
PropertyUtils.copyProperties(bean1, bean2);
However, as to your second question, you're trying to downcast an instance of a parent class to a child class?
I'm not sure how that would be legal in any OO language. Sure you can forcibly cast:
// This is not legal because you can't case from one class to anther
// unless the actual instance type (not the declared type of the variable,
// but the constructed type) is either the casted class or a subclass.
Parent p = new Parent();
Child c = (Child) p;
But you'd get a ClassCastException , since you can't treat an instance of a parent class as if it were a child class (only the other way around). Either of these would be legal however:
// This is legal because you're upcasting, which is fine
Child c = new Child();
Parent p = c;
// This is legal because the instance "p" is actually an
// instance of the "Child" class, so the downcast is legal.
Parent p = new Child();
Child c = (Child) p;
To answer your first question, you could easily write the code to copy property values between instances. It is easiest if you restrict properties to proper Objective-C properties (items declared using #property()) which is probably the best practice anyway. You can use the Objective-C runtime functions to get the list of all properties on a class (class_getPropertyList) and call property_getName() to get the property's name and call property_getAttributes() to make sure it is writeable. Then you can use NSObject's Key Value Coding to get and set the property values using valueForKeyPath: and setValueForKeyPath: respectively.
Some problems with you code example are that instances should be pointers. Second, you need an explicit cast since you are assigning an instance of a class to its super class. The reverse would not require a cast. That is probably why you are getting the warning.
The method BeanUtils.copyProperties
//.h
#import <Foundation/Foundation.h>
#import <objc/runtime.h>
#interface BeanUtils : NSObject
+(void)copyProperties:(id)src dest:(id)dest;
#end
//.m
#import "BeanUtils.h"
#implementation BeanUtils
+(void)copyProperties:(id)src dest:(id)dest {
NSLog(#"classeSrc=%# dst=%#", [src class], [dest class]);
if(src == NULL || dest == NULL) {
return;
}
Class clazz = [src class];
u_int count;
objc_property_t* properties = class_copyPropertyList(clazz, &count);
NSMutableArray* propertyArray = [NSMutableArray arrayWithCapacity:count];
for (int i = 0; i < count ; i++)
{
NSString *propertyName = [NSString stringWithUTF8String:property_getName(properties[i])];
[propertyArray addObject:propertyName];
//on verifie que la prop existe dans la classe dest
objc_property_t prop = class_getProperty([dest class], [propertyName UTF8String]);
if(prop != NULL) {
id result = [src valueForKey:propertyName];
[dest setValue:result forKey: propertyName];
}
else {
[NSException raise:NSInternalInconsistencyException format:#"La propriété %# n'existe pas dans la classe %#",propertyName, [dest class] ];
}
}
free(properties);
}
#end
call :
EleveBean *eleveBean = [EleveBean new];
eleveBean.nom = #"bob";
eleveBean.prenom = #"john";
tns1_EleveBean *tnsEleve = [tns1_EleveBean new];
[BeanUtils copyProperties:eleveBean dest:tnsEleve];
STAssertEquals(eleveBean.nom, tnsEleve.nom, #"");
STAssertEquals(eleveBean.prenom, tnsEleve.prenom, #"");
This question uses CLLocationCoordinate2D as an example, but this applies to other structs as well, such as CGPoint (although ones like those are usually automatically included).
I want to use CLLocationCoordinate2D as a return value in a class method. If it were an object you could write the following at the top and it would be fine, as long as the .m file had a reference to CoreLocation.h
#class ClassName
Is there an equivalent way of telling the compiler not to worry about the struct without re-declaring it or importing the header file into the class' header file?
I do not want to import CoreLocation.h into the header file, since that would mean every file that imports that header file would inherit CoreLocation.
Thanks
I'm not totally getting the point why you do not want to import CoreLocation, but CLLocationCoordinate2D is declared in CoreLocation.h. I'm not aware about a method like #class for struct and I don't think it exists since struct are C types.
What you can do is create your own class that wraps the CLLocationCoordinate2D or return the NSValue from it, or (why not?) a dictionary.
Easiest way to do this is to just use an object instead of the struct, then you can use the #class keyword. In this case, the CLLocation object works just fine. Alternatively you can often use an NSDictionary in place of a struct, but an object is a bit easier to manage.
You return a struct like any other type. But you should be aware that when returning a struct you are returning a copy of the internal value on the stack as a temporary variable. Unlike an Objective-C object where you are actually returning a pointer.
The type you return MUST be a complete type. That means, in your method declaration you need the definition of the struct. In your case, that means, you need to include the header.
For example:
typedef struct MyStruct {
int a;
int b;
} MyStruct;
#interface MyClass : NSObject
+(MyStruct) theStruct;
#end
#implementation MyClass
+(MyStruct) theStruct {
MyStruct s = {.a = 1, .b = 2};
return s;
}
#end
int main(int argc, const char * argv[])
{
#autoreleasepool {
MyStruct s1 = [MyClass theStruct];
s1.a = 100;
s1.b = 100;
NSLog(#"s1 = {%d, %d}", s1.a, s1.b);
NSLog(#"MyStruct.theStruct = {%d, %d}", [MyClass theStruct].a, [MyClass theStruct].b);
[MyClass theStruct].a = 0; // has no effect!
}
return 0;
}
Prints:
s1 = {100, 100}
MyStruct.theStruct = {1, 2}
There is no straightforward way of doing that with single keyword.
Here you can find why it is not straightforward, although it is stated that it is not possible to do that, somewhat true but not completely.
Forward declare a struct in Objective-C
And here is the workaround of doing this
Forward declare structs in Objective C
Hope this will help.