Give struct the status it deserves

[Stewart Gordon]

Hong wrote:
> Structs are second class citizens of... or maybe refugees of D, they are victims
> of discrimination.
> Following are the reasons:
> 
> 1. most D programmers don't use struct, unless they happen to be the poor guy
> writing the C interface.

Or they are writing or using a D interface to a C or other foreign API. 
  Or they want to save the overhead of memory allocation by using a 
lightweight alternative for those situations where the power of classes 
isn't needed.  Or they are interfacing a binary file format.

> 2. to use structs you have to use pointers, but the spec says pointers are only
> provided for C compatibility, structs are to be avoided as long as the world
> spins.

No I don't.  What are you talking about?

> 3. pointers + overloaded operators make a mess.... this is a less offensive
> example: (*o) = (*t)[(*i) * (*j)] ... the pointers and operators are abusing
> each other.
> 
> 4. structs cannot have constructor, "static opCall" is best you can do.

What's wrong with that?  Do you simply miss the word "new" in uses of 
static opCall?

> 5. structs are more efficient? Not when structs are passed around by value. To
> change a struct member: 1. make a copy 2. change the copy 3. Copy the copy back
> into the original location. Two damned copies for.... efficiency.

If you want classes, you know where to find them.

> 6. yes, you can use pointers to change a struct member without copying, if you
> can be bothered to define 2 accessor methods, one returns a copy another one
> returns a pointer.

Why would anyone want to do that?  What's wrong with simply

     Qwert yuiop = asdfg;    // to create a copy
     Qwert* zxcvb = &asdfg;  // to create a pointer

> 7. Most standard containers (DTL) do not allow a pointer to a contained struct
> to be retrieved, all changes, or just about anything has to be done via copies.

That's an issue with those containers, rather than with structs themselves.

> 8. structs have different behaviours between array and Vector, array [] returns
> a reference, Vector [] returns a copy, nice rookie trap.
> 
> Imho, following are little suggestions for structs to make first class citizens
> of D:
> 
> 1. have some sort of reference semantic to replace pointers. Pointers are not
> necessary unless structs are used with "new"
> 
> 2. add constructor for struct, destructors are not necessary.
> 
> I use structs because I need efficiency and stack allocated data structures,
> however, it is painful to see a C++ program turns into a C like program when
> ported to D.

Maybe you could elaborate on how these reference semantics would work 
such that they'd be any different from classes.

Stewart.

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