How to get a range from std.container.array for use with std.format.sformat?
Steven Schveighoffer
schveiguy at yahoo.com
Tue Jan 30 18:42:45 UTC 2018
On 1/30/18 12:53 PM, cc wrote:
> import std.container;
> import std.format;
> Array!char str;
> str.length = 256;
>
> str.sformat!"%s:%s"("some", "string");
> // Error: template std.format.sformat cannot deduce function from
> argument types !("%s:%s")(Array!char, string, string), candidates are:
> // std.format.sformat(alias fmt, Args...)(char[] buf, Args args)
> if (isSomeString!(typeof(fmt)))
> // std.format.sformat(Char, Args...)(char[] buf, in Char[] fmt,
> Args args)
sformat requires a builtin array, apparently. It doesn't work for other
types.
>
> auto rng = cast(char[]) str[];
> // Error: cannot cast expression `str.opSlice()` of type
> `RangeT!(Array!char)` to `char[]`
why not just auto rng = str[]?
> Additionally, would sformat cause GC allocations even when writing to a
> preallocated buffer?
Not directly. If sformat needs to call a function on what you are asking
to format that would use the GC, then it would not be @nogc.
-Steve
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