This is a rather crazy idea I got a while back. It's somewhat related to #17158
The original issue was to allow translation strings in other translations, but this has some issues with compatibility.

So I came-up with something much more advanced and less likely to cause conflicts.

I was already planning on building this in time as a component and Bundle, but having it in the Symfony core would be a better fit (if possible).

The idea is to allow Expressions in a translator string.

Example:

Hello {$ user.gender == 'male' ? 'Sir' : 'Madam' $},

{$ trans('something') $}

Today date is {$ 'now'|date('d-m-Y') $}.

I think it's very unlikely for anyone to have this in the translator keys 😄 but it will open a whole new level of possibilities. The only main challenge is performance, caching is almost mandatory here.

We can store the translation-expression as compiled down PHP for fast execution or convert the whole translation to an expression like:

'Hello ' ~ (user.gender == 'male' ? 'Sir' : 'Madam') ~ ',

Today date is ' ~ (date_format('now', 'd-m-Y')) ~'.'

Which can be stored using the expression engines caching system.

Suggestions and comments are more then welcome 👍