Hi All,

The problem is that I want to disable the use of boolean type. But this is not possible with contract programming or otherwise. Actually, it's possible to fix it with contract programming or otherwise throwing errors.

alias ir = inclusiveRange;
auto inclusiveRange(T = int)(T f = T(0), T l = T(0), T s = T(1))
in(!is(T == bool), "Boolean type cannot be used!") {/*
{
  static if(is(T == bool))
  {
    import std.format;
  	assert(false, format("This type (%s) cannot be used!", typeid(T)));
  }//*/
  if(!l) {
    l = f;
    f = 0;
  }
  return InclusiveRange!T(f, l, s);
} /* Error:
   * operation not allowed on `bool` `this.last -= this.step`
   */

However, the compiler catches other errors! How can I solve this problem?

Thanks...

SDB@79

On Tuesday, 10 May 2022 at 09:26:46 UTC, Salih Dincer wrote:

What about something like this?

auto inclusiveRange(T = int)(T f = T(0), T l = T(0), T s = T(1))
if(!is(T == bool))
{
    //...
}

On Tuesday, 10 May 2022 at 12:56:50 UTC, frame wrote:

auto inclusiveRange(T = int)(T f = T(0), T l = T(0), T s = T(1))
if(!is(T == bool))
{
    //...
}

Not compiled, the compiler returns:

SDB@79

On Tuesday, 10 May 2022 at 13:14:20 UTC, Salih Dincer wrote:

That is your type protection here, a constraint.

Alternatively you can put the constraint in a function and make it more verbose:

bool isAllowedType(T)()
{
    static assert(!is(T == bool), "Nope");
    return true;
}

void fun(T = int)(T arg)
if(isAllowedType!T)
{
    //..
}

fun(0);      // ok
fun(false);  // not allowed

On Tuesday, 10 May 2022 at 14:42:31 UTC, Ali Çehreli wrote:

Here that is:

void inclusiveRange(T)(T Args...) if(is(T == bool)) {
  assert(0, "\nBoolean type cannot be used!");
}/*
core.exception.AssertError@InclusiveRangev2.d(79):
Boolean type cannot be used!
----------------
??:? _d_assert_msg [0x55e17c3c881e]
??:? pure nothrow @safe void source.inclusiveRange!(bool).inclusiveRange(bool...) [0x55e17c3c575f]
??:? _Dmain [0x55e17c3a8e43]
Process finished with exit code 1.
*/

Tuesday, 10 May 2022 at 14:44:06 UTC, frame wrote:

Thank you, I solved the problem by adding a second function.

D, you are great!

SDB@79