hasMobileElements

Returns true iff R is an input range that supports the moveFront primitive, as well as moveBack and moveAt if it's a bidirectional or random access range. These may be explicitly implemented, or may work via the default behavior of the module level functions moveFront and friends. The following code should compile for any range with mobile elements.

alias E = ElementType!R;
R r;
static assert(isInputRange!R);
static assert(is(typeof(moveFront(r)) == E));
static if (isBidirectionalRange!R)
    static assert(is(typeof(moveBack(r)) == E));
static if (isRandomAccessRange!R)
    static assert(is(typeof(moveAt(r, 0)) == E));

Examples

import std.algorithm.iteration : map;
import std.range : iota, repeat;

static struct HasPostblit
{
    this(this) {}
}

auto nonMobile = map!"a"(repeat(HasPostblit.init));
static assert(!hasMobileElements!(typeof(nonMobile)));
static assert( hasMobileElements!(int[]));
static assert( hasMobileElements!(inout(int)[]));
static assert( hasMobileElements!(typeof(iota(1000))));

static assert( hasMobileElements!( string));
static assert( hasMobileElements!(dstring));
static assert( hasMobileElements!( char[]));
static assert( hasMobileElements!(dchar[]));

The OpenD Programming Language

hasMobileElements

Examples

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