Firefox interprets function statements differently and apparently they broke declaration hoisting for the function declaration. ( A good read about named functions / declaration vs expression ) Why does Firefox interpret statements differently is because of the following code: if ( true ) { function test(){alert(“YAY”);} } else { function test(){alert(“FAIL”);} } test(); // should … Read more
You can forward declare your own classes in header files to save compilation time. But you can’t for classes in namespace std. According to the C++11 standard, 17.6.4.2.1: The behavior of a C++ program is undefined if it adds declarations or definitions to namespace std or to a namespace within namespace std unless otherwise specified. … Read more
C++ (like C) was designed to be implementable by a single-pass compiler. Forward references are necessary in cases where the compiler needs to know that a symbol refers to a class before the class is actually defined. The classic example of this is when two classes need to contain pointers to each other. i.e. class … Read more
This has been standardized, proposal 2764: Forward declaration of enumerations (rev. 3) allowed the forward declaration of enums if you specify the underlying type, whereas before this was not possible. The main reason is that when the underlying type is not specified the size is implementation defined and can depend on the enumerator values. From … Read more
You can’t forward declare members. Instead, bar.cpp should #include both foo.h and bar.h. Problem solved. In general, if you use the sequence: Forward declare all class types Define all class types Bodies of class members everything will be fine.
You can work around it by declaring an ancestor class: type TBaseElement = class end; TMyCollection<T: TBaseElement> = class end; TMyElement = class(TBaseElement) private FParent: TMyCollection<TBaseElement>; end;
C++ Standard ISO/IEC 14882:2003(E) 7.3.1.2 Namespace member definitions Paragraph 3 Every name first declared in a namespace is a member of that namespace. If a friend declaration in a non-local class first declares a class or function (this implies that the name of the class or function is unqualified) the friend class or function is … Read more
Use forward declaration when possible. Suppose you want to define a new class B that uses objects of class A. B only uses references or pointers to A. Use forward declaration then you don’t need to include <A.h>. This will in turn speed a little bit the compilation. class A ; class B { private: … Read more
A struct (without a typedef) often needs to (or should) be with the keyword struct when used. struct A; // forward declaration void function( struct A *a ); // using the ‘incomplete’ type only as pointer If you typedef your struct you can leave out the struct keyword. typedef struct A A; // forward declaration … Read more
Great question. I use a pattern like this for most of my scripts: #!/bin/bash main() { foo bar baz } foo() { } bar() { } baz() { } main “$@” You can read the code from top to bottom, but it doesn’t actually start executing until the last line. By passing “$@” to main() … Read more