digitalmars.D.learn - How to get a range from std.container.array for use with
- cc (17/17) Jan 30 2018 import std.container;
- Steven Schveighoffer (7/25) Jan 30 2018 sformat requires a builtin array, apparently. It doesn't work for other
- cc (6/6) Jan 30 2018 Still doesn't work without the cast it seems..
- Steven Schveighoffer (10/16) Jan 31 2018 I misunderstood what you were trying to do. I thought you were just
- Seb (24/40) Jan 30 2018 For everything else, you can use formattedWrite:
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) auto rng = cast(char[]) str[]; // Error: cannot cast expression `str.opSlice()` of type `RangeT!(Array!char)` to `char[]` Additionally, would sformat cause GC allocations even when writing to a preallocated buffer?
Jan 30 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
Jan 30 2018
Still doesn't work without the cast it seems.. auto rng = str[]; rng.sformat!"%s:%s"("some", "string"); // Error: template std.format.sformat cannot deduce function from argument types !("%s:%s")(RangeT!(Array!char), string, string)
Jan 30 2018
On 1/30/18 2:19 PM, cc wrote:Still doesn't work without the cast it seems.. auto rng = str[]; rng.sformat!"%s:%s"("some", "string"); // Error: template std.format.sformat cannot deduce function from argument types !("%s:%s")(RangeT!(Array!char), string, string)I misunderstood what you were trying to do. I thought you were just trying to get a valid range, missed the requirement that the range works with sformat (obviously from the subject! sorry). Indeed, there isn't a way to extract an actual char[] from Array (and this is intentional). But as Seb says, you can use formattedWrite: auto rng = str[]; rng.formattedWrite("%s:%s", "some", "string"); -Steve
Jan 31 2018
On Tuesday, 30 January 2018 at 18:42:45 UTC, Steven Schveighoffer wrote:On 1/30/18 12:53 PM, cc wrote:For everything else, you can use formattedWrite: ``` import std.array : appender; auto writer = appender!string(); writer.formattedWrite!"%s is the ultimate %s."(42, "answer"); writeln(writer.data); ``` without any GC: ``` /+dub.sdl: dependency "emsi_containers" version="~>0.6.0" +/ import std.format, std.stdio; void main() { import containers; DynamicArray!char arr; arr.formattedWrite!"%s is the ultimate %s."(42, "answer"); printf("%.*s\n", arr.length, arr.ptr); } ``` https://run.dlang.io/is/Taem9jimport 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.
Jan 30 2018