Re: toString best practices

[Paolo Invernizzi via Digitalmars-d-learn]

On Wednesday, 15 February 2023 at 12:15:18 UTC, Bastiaan Veelo 
wrote:
On Thursday, 9 February 2023 at 17:49:58 UTC, Paolo Invernizzi 
wrote:

```
import std.format, std.range.primitives;

struct Point(T)
{
T x, y;

void toString(W)(ref W writer, scope const ref 
FormatSpec!char f) const

if (isOutputRange!(W, char))
{
put(writer, "(");
formatValue(writer, x, f);
put(writer, ", ");
formatValue(writer, y, f);
put(writer, ")");
}
}

void main(){

import std.format : format;
assert( format("%s", Point!int(1,2)) == "(1, 2)");

import std.experimental.logger;
sharedLog.infof("%s", Point!int(1,2));
}
```


Pasting this into https://run.dlang.io/, it just works. That's 
for DMD 2.099, so it might be a regression -- or recent feature?


-- Bastiaan.


Hi Bastiaan,

I think the cause is in some change happened in the logger 
module, I'm recompiling some code with the latest dmd frontend.


I solved it simply using the 'logX' functions at module level 
instead of the sharedLog methods.


Thank you!

Re: toString best practices

[Bastiaan Veelo via Digitalmars-d-learn]

On Thursday, 9 February 2023 at 17:49:58 UTC, Paolo Invernizzi 
wrote:

```
import std.format, std.range.primitives;

struct Point(T)
{
T x, y;

void toString(W)(ref W writer, scope const ref 
FormatSpec!char f) const

if (isOutputRange!(W, char))
{
put(writer, "(");
formatValue(writer, x, f);
put(writer, ", ");
formatValue(writer, y, f);
put(writer, ")");
}
}

void main(){

import std.format : format;
assert( format("%s", Point!int(1,2)) == "(1, 2)");

import std.experimental.logger;
sharedLog.infof("%s", Point!int(1,2));
}
```


Pasting this into https://run.dlang.io/, it just works. That's 
for DMD 2.099, so it might be a regression -- or recent feature?


-- Bastiaan.

toString best practices

[Paolo Invernizzi via Digitalmars-d-learn]

Hello everybody,

Let's assume there's an implementation of a templated struct like 
this:


```
import std.format, std.range.primitives;

struct Point(T)
{
T x, y;

void toString(W)(ref W writer, scope const ref 
FormatSpec!char f) const

if (isOutputRange!(W, char))
{
put(writer, "(");
formatValue(writer, x, f);
put(writer, ", ");
formatValue(writer, y, f);
put(writer, ")");
}
}

void main(){

import std.format : format;
assert( format("%s", Point!int(1,2)) == "(1, 2)");

import std.experimental.logger;
sharedLog.infof("%s", Point!int(1,2));
/+
 Error: none of the overloads of template 
`std.logger.core.Logger.memLogFunctions!LogLevel.info.logImplf` 
are callable using argument types `!()(string, Point!int) shared`

/Users/pinver/dlang/dmd-2.102.0/osx/bin/../../src/phobos/std/logger/core.d(828,14):
Candidates are: `logImplf(int line = __LINE__, string file = __FILE__, 
string funcName = __FUNCTION__, string prettyFuncName = __PRETTY_FUNCTION__, 
string moduleName = __MODULE__, A...)(lazy bool condition, lazy string msg, 
lazy A args)`
/Users/pinver/dlang/dmd-2.102.0/osx/bin/../../src/phobos/std/logger/core.d(876,14):
`logImplf(int line = __LINE__, string file = __FILE__, 
string funcName = __FUNCTION__, string prettyFuncName = __PRETTY_FUNCTION__, 
string moduleName = __MODULE__, A...)(lazy string msg, lazy A args)`
+/

}
```

What is the best way to handle also shared writers?

Thank you all,
Paolo