• sclytrack (7/7) Oct 29 2014 As Stewart Gordon mentioned before (2012)
• Simon A (27/27) Oct 30 2014 I don't know about syntax, but D sure needs first-class support
• sclytrack (4/6) Oct 30 2014 struct A
• sclytrack (21/23) Oct 30 2014 struct A
• Dicebot (1/1) Nov 01 2014 http://dlang.org/phobos/std_typecons.html#.Rebindable

"sclytrack" <sclytrack fake.com> writes:

As Stewart Gordon mentioned before (2012)

What about adding tailConst to the D programming language?


tailConst MyStruct a;

All fields of the MyStruct would be tailConst and ...



tailConst MyClass b;

would make the the pointer mutable but all the fields of b const.



...tailImmutable, ...

"Simon A" <simon_a example.com> writes:

I don't know about syntax, but D sure needs first-class support 
of tail immutability.

Take this code for example:

---

immutable class C
{
	void foo()
	{
		//
	}
}

void main()
{
	auto c = new C();
	c.foo();
}

---

Compile it and get

Error: immutable method C.foo is not callable using a mutable 
object

Why?  Because foo() is immutable and demands an immutable this 
reference.  The C instance c is only tail immutable, which 
doesn't really count for anything.  (So, "new C()" instead of 
"new immutable(C)()" is legal but pretty much unusable, it seems.)

But why should *any* function require an immutable reference, as 
opposed to a tail immutable reference?  (Similarly for shared vs 
tail shared.)

"sclytrack" <fake hotmail.com> writes:

On Thursday, 30 October 2014 at 10:28:42 UTC, Simon A wrote:
 I don't know about syntax, but D sure needs first-class support 
 of tail immutability.


struct A
{

}

"sclytrack" <sclytrack fake.com> writes:

On Thursday, 30 October 2014 at 10:28:42 UTC, Simon A wrote:
 I don't know about syntax, but D sure needs first-class support 
 of tail immutability.

struct A
{
   float * a;

   void foo() tailconst
   {
      writeln(typeof(a).stringof);  //outputs "const(float) *"
   }
}


class B
{
   float * a;

   void foo() tailconst
   {
      writeln(typeof(this).stringof);  //outputs "tailconst(B)"
      writeln(typeof(a).stringof);     //outputs "const float *"
   }
}

tailconst for struct and classes.

How about this?


*sorry about the previous almost empty post.