Comments on: Const Constructors

By: Mark

Mark — Sat, 29 Oct 2005 01:06:13 +0000

For me, separate classes give off a strong code-smell. With your solution, client code could do confusing stuff like:
const ReadWriteFoo crwf;
mutable ReadOnlyFoo mrof;

If you haven’t read Kevlin’s proposal, I highly recommend it, because he gives several “real world” use cases for const constructors.

By: Bheeshmar

Bheeshmar — Fri, 28 Oct 2005 20:18:22 +0000

Why are two classes untenable? You have two distinct behaviors. One could even be implemented in terms of the other:

class ReadOnlyFoo
{
public:
ReadOnlyFoo( const T … ) {}
void fubarize() const { … }
};

class ReadWriteFoo
{
public:
ReadWriteFoo() rofPtr(0) {}
~ReadWriteFoo() { delete rofPtr; }
void set(const T value) { rofPtr= new RoadOnlyFoo(value); }
void fubarize() { if( rofPtr ) rofPtr->fubarize(); else throw … ; }
private:
ReadOnlyFoo * rofPtr;
};

By: Hillary

Hillary — Thu, 27 Oct 2005 02:08:22 +0000

Ok Mark. I am commenting on your entry. I feel it was a little bit on the boring side. I recommend throwing in a comparison now and then, such as, C++ and Oprah, or C++ and chocolate cake. I would really like if you could do that from now on. Thank you.