Twig: How to concat and translate strings?

Question

I tried the answers of this question, but it's not working. It's weird and I cannot reproduce the behavior:

I cleared the cache
Concat works (it output's the right string)
The concated string as a variable is not translateable
The concated string pasted as a string is translateable
Edit: obj2arr casts the object to an array, to make it iterable. prepareForTwig is just using trim(), etc. - the string is outputted correctly.
Edit 2: {% set transVar = (key|prepareForTwig) %} (without prefix) doesn't work as well.

yml:

# Resources/translations/messages.en.yml
my:
   keywords:
       keyword1: K1
       keyword2: K2
       # ...

twig:

{# my.twig.html #}
{% for key, value in data|obj2arr %}
    {% set transVar = 'my.keywords.' ~ (key|prepareForTwig)) %}

    {{ transVar }}<br/>                    {# output, e.g.: my.keywords.keyword1 #}
    {{ transVar|trans}}<br/>               {# output, e.g.: my.keywords.keyword1 #}  
    {{ 'my.keywords.keyword1'|trans }}     {# output: K1 #}
{% endfor %}

EDIT:

CustomTwigExtension.php

class CustomTwigExtension extends \Twig_Extension
{
    public function getFilters()
    {
        return array(
            new \Twig_SimpleFilter('obj2arr', array($this, 'obj2arrFilter')),
            new \Twig_SimpleFilter('prepareForTwig', array($this, 'prepareForTwigFilter')),
        );
    }

    public function obj2arrFilter($obj)
    {
        return (array)$obj;
    }

    public function prepareForTwigFilter($str) {
        $str = trim($str);
        $str = strtolower($str);
        $str = substr($str, 2, strlen($str)); // obj2arr() prefixes "*"

        return $str;
    }

    public function getName()
    {
        return 'custom_twig_extension';
    }
}

Thanks in advance!

Did you tried using parentesis, like `{{ (transVar) | trans }}`? — Artamiel, Oct 19 '15 at 08:50
Be sure to check twice. I myself tried it right now with `{{ ('hello.world.' ~ myVar) | trans }}` where `myVar` is set to `'message'` and it got translated correctly. — Artamiel, Oct 19 '15 at 09:02
@Artamiel The problem is not the syntax, I guess. If I paste the concated string, it works. Maybe `obj2arr` and `prepareForTwig` are responsible for the weird issue. But I have no idea how this could affect the translation. The outputted, concated string is right. — Mr. B., Oct 19 '15 at 09:09
The issue happens because you are trying to have twig evaluate a variable and then use it as a twig construct. This is usally not available, but you can make it work using Twig's template_from_string function: http://twig.sensiolabs.org/doc/functions/template_from_string.html — Carlos Granados, Oct 19 '15 at 09:13
@CarlosGranados I tried `{{ include(template_from_string("{{ transVar|trans }}")) }}` - same result as above. Did you mean it this way? — Mr. B., Oct 19 '15 at 09:21
What happens if you try it this way - `{% set transVar = key | prepareForTwig %}` and then output it like `{{ 'my.keywords.' ~ transVar | trans }}` — Artamiel, Oct 19 '15 at 09:23
Use {{ include(template_from_string("{{ '" ~ transVar ~ "'|trans }}")) }} — Carlos Granados, Oct 19 '15 at 09:25
This last solution should work. Have you copied it exactly as I input it? Notice that there is a ' character within the " character, it is not easy to see. — Carlos Granados, Oct 19 '15 at 09:33
Also, did you activate the template_from_string function? It is not active by default — Carlos Granados, Oct 19 '15 at 09:34
You custom twig extension has nothing to do with this problem — Carlos Granados, Oct 19 '15 at 09:35
@CarlosGranados Yes, I copied your code and activated the function. I just added the code of my custom twig extension. Maybe there's anything wrong (unlikely). — Mr. B., Oct 19 '15 at 09:36

Rmy5 · Answer 1 · 2020-07-10T11:10:17.767

5

Others examples didn't seem to work in my case, this is what I ended up using:

{{ "my.prefix.#{ myVariable }.my.postfix" | trans }}

The translation string has to be between double quotes.

edited Jul 10 '20 at 11:10

answered Jun 29 '20 at 16:24

Rmy5

527
8
21

Just a small note, opening brackets should be ```{{``` not ```{%``` – pusle Jul 09 '20 at 10:40

score 1 · Accepted Answer · answered Oct 20 '15 at 16:58

Every answer of outputting concated translationstrings was right, example:

{% 'my.prefix.' ~ extendByKeyword | trans }}

The problem was a weird generated space:

(array) $obj added * (there are two spaces after the star) as a prefix to the key-variable.
I used substr() to get rid of the * (star + 1 space), but didn't notice/expect the second space.
After comparing the strings with strlen(), I found the cause.

Thanks to @Artamiel and @CarlosGranados for your help.

Twig: How to concat and translate strings?

2 Answers2