Re: One case of array assignments

[monarch_dodra]

On Monday, 18 March 2013 at 21:35:43 UTC, Chris Nicholson-Sauls 
wrote:
On Thursday, 14 March 2013 at 01:34:02 UTC, Marco Leise wrote:
Am Wed, 13 Mar 2013 14:31:42 -0700
schrieb "H. S. Teoh" <hst...@quickfur.ath.cx>:
Why is it bad to have to explicitly list the elements for 
static
initialization?

Because of:

struct CompressionData
{
        ubyte[4096] x =
[0,0,0 /* ...ad nauseum... */ ,0,0];
}

struct CompressionData
{
    ubyte[4096] x; // note this is already [0...0] thanks
                   // to default init... but still:

    this ()
    {
        x[] = 0;
    }
}

The downside here is that this requires run-time initialization.

--- Or even: ---

import std.range;

struct CompressionData
{
    ubyte[4096] x = repeat( 0 )[ 0 .. 4096 ];
}

Assuming repeat()[] is CTFE-able (didn't test).

Better, but that doesn't compime, because "repeat( 0 )[ 0 .. 4096 
]" is not an actual array, but a complex type. And of type int. 
The correct code would be:

ubyte[4096] x = repeat( cast(ubyte)0 )[ 0 .. 4096 ].array();

This can be used as-is inside normal code. Hwoever, array is not 
CTFE-able, so it can't work to define a struct T.init value.