Re: Template with default parameter
On Friday, 11 March 2022 at 04:41:40 UTC, Andrey Zherikov wrote:
I have simple template:
```d
template T(int i=3)
{
mixin template M(int m)
{
enum t = i;
}
}
{
mixin T!1.M!1;
pragma(msg, t); // 1
}
{
mixin T!().M!1;
pragma(msg, t); // 3
}
{
mixin T.M!1; // Error: identifier `M` of `T.M` is not
defined
// Error: mixin `M!1` is not defined
pragma(msg, t); // Error: undefined identifier `t`
//while evaluating
`pragma(msg, t)`
}
```
What should I do to be able to write `T.M!...`? I want to omit
verbose `!()` for `T`. Note that mixins are essential here.
Create an alias for T!() is the best you can do.
Ex.
```
alias t = T!();
```
There isn't really any better method as far as I know.
Re: gdc or ldc for faster programs?
On Tuesday, 25 January 2022 at 20:04:04 UTC, Adam D Ruppe wrote: Not surprising at all: gdc is excellent and underrated in the community. The performance metrics are just a bonus. Gdc is the main reason I can get my worksite to take D seriously since we're a traditional unix shop (solaris -> linux). The gcd crew are doing a *huge* service for the community.
Template with default parameter
I have simple template:
```d
template T(int i=3)
{
mixin template M(int m)
{
enum t = i;
}
}
{
mixin T!1.M!1;
pragma(msg, t); // 1
}
{
mixin T!().M!1;
pragma(msg, t); // 3
}
{
mixin T.M!1; // Error: identifier `M` of `T.M` is not
defined
// Error: mixin `M!1` is not defined
pragma(msg, t); // Error: undefined identifier `t`
//while evaluating
`pragma(msg, t)`
}
```
What should I do to be able to write `T.M!...`? I want to omit
verbose `!()` for `T`. Note that mixins are essential here.
Re: Write UTF-8 bytes directly to stack buffer
On Thu, Mar 10, 2022 at 05:39:34PM +, Chris Piker via Digitalmars-d-learn
wrote:
> Hi D
>
> There are quite a few string, array and range functions in phobos so
> I'm getting confused as to the right way to encode string data as
> UTF-8 directly into a stack buffer while keeping track of the write
> point.
>
> I have some output packets I'm building up in a tight loop. For speed
> I'm using the a priori knowledge that output packets will never be
> larger then 64K. So what's the best way to do this:
>
> ```d
> ubyte[65536] buf;
> ubyte[] usable_buf = buf;
>
> // part of some tight loop, how to create function writef_utf8 ?
> foreach(input_thing; things){
> usable_buf.writef_utf8!"format str"(input_thing.fieldA,
> input_thing.fieldB);
> }
>
> size_t used = buf.length - usable_buf.length;
> stdout.write(buf[0.. used]);
>
> ```
Probably what you're looking for is std.format.formattedWrite. For
example:
--
import std;
void main() {
ubyte[65536] buf;
char[] usable_buf = cast(char[]) buf[];
usable_buf.formattedWrite!"Blah %d blah %s"(123, "Это UTF-8 строка.");
auto used = buf.length - usable_buf.length;
writefln("%(%02X %)", buf[0 .. used]);
}
--
D strings are UTF-8 by default, so for the most part, you don't need to
worry about it.
T
--
Guns don't kill people. Bullets do.
Write UTF-8 bytes directly to stack buffer
Hi D
There are quite a few string, array and range functions in phobos
so I'm getting confused as to the right way to encode string data
as UTF-8 directly into a stack buffer while keeping track of the
write point.
I have some output packets I'm building up in a tight loop. For
speed I'm using the a priori knowledge that output packets will
never be larger then 64K. So what's the best way to do this:
```d
ubyte[65536] buf;
ubyte[] usable_buf = buf;
// part of some tight loop, how to create function writef_utf8 ?
foreach(input_thing; things){
usable_buf.writef_utf8!"format str"(input_thing.fieldA,
input_thing.fieldB);
}
size_t used = buf.length - usable_buf.length;
stdout.write(buf[0.. used]);
```
