[Development] format-like tr()

[Ivan Solovev]

Hi Volker,

> From my understanding, the idea behind the std::format framework would be
> to have a “cardinality" type for which we can implement a special formatter,
> allowing “whatever” to be in the format specification.

True, but the custom formatter specialization is called when the argument id
is already parsed.
In your example:

  std::format("{0:Cardinality}", Cardinality{42});

the std implementation parses the "{0:" part, extracting the argument id == 0,
and then passes the rest of the string to the std::formatter<Cardinality>
specialization.

IIUC, Thiago suggested to use 'n' instead of the argument id.

------------------------------

Ivan Solovev
Senior Software Engineer

The Qt Company GmbH
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ivan.solovev at qt.io
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________________________________________
From: Development <development-bounces at qt-project.org> on behalf of Volker Hilsheimer via Development <development at qt-project.org>
Sent: Thursday, October 24, 2024 9:43 AM
To: Macieira, Thiago; development at qt-project.org
Cc: albert astals cid; Volker Krause
Subject: Re: [Development] format-like tr()

> On 23 Oct 2024, at 22:55, Thiago Macieira <thiago.macieira at intel.com> wrote:
>>> a) keep the "n" and make it mandatory, as in {n}
>>
>> If we use std::format, then we cannot do it, because it does the
>> argument index parsing on its own, and delegates to a custom formatter
>> specialization after that. And argument index can only be a non-negative
>> integer value.
>
> Ok, so if we use their parser, the number must be {0} or the only, right? How
> do we communicate to translators and tooling that this a plural form?

>From my understanding, the idea behind the std::format framework would be to have a “cardinality" type for which we can implement a special formatter, allowing “whatever” to be in the format specification.

https://godbolt.org/z/j6avb6afr

Still supporting all the standard format specifications for integers is then an exercise I didn’t try.

> Should we bring this to SG16 and ask for their long-term idea (C++26 or 29)?


Always good to remind the committee that user interfaces are a thing ;)


Volker

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