Why does this declaration exist inside std.range.put?
Steven Schveighoffer via Digitalmars-d-learn
digitalmars-d-learn at puremagic.com
Thu Nov 6 13:57:36 PST 2014
On 11/6/14 4:19 PM, Meta wrote:
> This is the code for std.range.put:
>
> void put(R, E)(ref R r, E e)
> {
> //Why?
> @property ref E[] EArrayInit(); //@@@9186@@@: Can't use (E[]).init
>
> //First level: simply straight up put.
> static if (is(typeof(doPut(r, e))))
> {
> doPut(r, e);
> }
> //Optional optimization block for straight up array to array copy.
> else static if (isDynamicArray!R && !isNarrowString!R &&
> isDynamicArray!E && is(typeof(r[] = e[])))
> {
> immutable len = e.length;
> r[0 .. len] = e[];
> r = r[len .. $];
> }
> //Accepts E[] ?
> else static if (is(typeof(doPut(r, [e]))) && !isDynamicArray!R)
> {
> if (__ctfe)
> doPut(r, [e]);
> else
> doPut(r, (&e)[0..1]);
> }
> //special case for char to string.
> else static if (isSomeChar!E && is(typeof(putChar(r, e))))
> {
> putChar(r, e);
> }
> //Extract each element from the range
> //We can use "put" here, so we can recursively test a RoR of E.
> else static if (isInputRange!E && is(typeof(put(r, e.front))))
> {
> //Special optimization: If E is a narrow string, and r accepts
> characters no-wider than the string's
> //Then simply feed the characters 1 by 1.
> static if (isNarrowString!E && (
> (is(E : const char[]) && is(typeof(doPut(r, char.max))) &&
> !is(typeof(doPut(r, dchar.max))) && !is(typeof(doPut(r, wchar.max)))) ||
> (is(E : const wchar[]) && is(typeof(doPut(r, wchar.max)))
> && !is(typeof(doPut(r, dchar.max)))) ) )
> {
> foreach(c; e)
> doPut(r, c);
> }
> else
> {
> for (; !e.empty; e.popFront())
> put(r, e.front);
> }
> }
> else
> {
> import std.string;
> static assert (false, format("Cannot put a %s into a %s.",
> E.stringof, R.stringof));
> }
> }
>
> What is the reason for that first function declaration, EArrayInit? It's
> not referenced anywhere else in the function, and it doesn't even have a
> body.
github blame is quite useful:
https://github.com/D-Programming-Language/phobos/blame/master/std/range.d#L668
The commit:
https://github.com/D-Programming-Language/phobos/commit/c717b503e7305a92410c23ca2bc2ea14b40f8aa2
It apparently was used when it was added, but is no longer used. Here is
the commit that removed the use:
https://github.com/D-Programming-Language/phobos/commit/87c71e6e14c3e9365a2cbf10105d7e6854824275
I think it can be safely removed.
-Steve
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