call twig function from custom twig function - symfony

Question

I created a custom twig function in AppExtension Class. I need to call form_label() from this new function. ¿Is it posible? I tried but does not work:
from template I call:
{{ myFunc(form.someField) }}
public function myFunc( $field )
{
$html = form_label($field);
}
The idea is to render each form field in a different order/way than the form_widget(form) twig function. The "form_label()" function it's not reconized.
Thx for any suggestion.

Answer 1

I feel like this is the wrong approach to handle this. Extensions are for transforming data not really to manipulate the form definition itself.
First of all the order is defined as in the form type, so you can swap those around. To render the fields differently you can use form themes, or even rendering a custom form type.
Alternatively if its a one time thing (you could also create a macro for this) you can also instead of form_widget(form) order them in the way you like.
{{ form_start(form) }}
{{ form_row(form.field3) }}
{{ form_row(form.field1, { attr: { class: 'im-different' } }) }}
{{ form_row(form.field2) }}
{{ form_end(form) }}
Or even go deeper.
{{ form_start(form) }}
{{ form_row(form.field3) }}
<div>
{{ form_label(form.field1) }}
{{ form_widget(form.field1) }}
{{ form_errors(form.field1) }}
</div>
{{ form_row(form.field2) }}
{{ form_end(form) }}
To see these functions and how they all rendered by default you can look at form_div_layout.html.twig.

Answer 2

I agree with Jenne van der Meer and Nico Haase that your approach isn't particularly optimal. If I had the choice, I would go a different route: Instead of rendering in your function, render in twig, then pass the result to the function (like {{ myFunc(form_label(form), form) }}). Since you omit what your function actually needs and/or does, it's hard to provide further advice. However, I'm absolutely sure, that rendering can be done in twig before or after entering your function, via a macro/block, maybe even a form theme).
However, if you really really require your function to render the form field ... the following will possibly help you. I strongly advise against doing this, there's probably a better suited solution.
The form_label function is slightly more complex than a simple function. Instead, it uses twig's compile mechanisms to generate specific php code. It will eventually call:
FormRenderer::searchAndRenderBlock(FormView $view, string $blockNameSuffix, array $variables = [])
Diving deep into the compiler, the template call form_label(form, options) would be turned into:
$this->env->getRuntime('Symfony\Component\Form\FormRenderer')->searchAndRenderBlock(
$form, 'label', $options
);
where the $this->env seems to be the twig environment. That means, to call this in your twig extension you need to have access to the proper Twig environment, and then it should already work with the recipe I just provided. Especially if you can omit the options argument, I didn't take a deeper look into how that one's assembled (but it's probably just straight forward).
So your twig function must be defined via:
public function getFunctions(): array
{
return [
new TwigFunction('myFunc', [&$this, 'myFunc'], [
'needs_environment' => true, // <--- this!
'is_safe' => ['html'],
]),
];
}
public function myFunc(\Twig\Environment $env, $field) {
// other stuff
$html = $env->getRuntime(\'Symfony\Component\Form\FormRenderer\')->searchAndRenderBlock(
$field, 'label', $options
);
return $html;
}