CODEWITHSUNDEEP
phpsymfonytwig
benoliver999
benoliver999

Reputation: 165

Making a custom latex escaper for twig

I have a twig template than generates a Latex file. It works fine except that it issues characters escaped for html.

So for instance, the DB returns the string Rosie & Jim.

Twig makes that Rosie & Jim.

For latex I need the & to actually render as \&.

Therefore I think I need a custom escaper for Latex as mentioned here: https://twig.sensiolabs.org/doc/2.x/filters/escape.html#custom-escapers

However, I'm a little green when it comes to twig and can't find any examples of actual escapers anywhere. Does anyone know:

a) Is this what I actually need?

b) What I actually need to do to make one?

Upvotes: 2

Views: 747

Answers (1)

benoliver999
benoliver999

Reputation: 165

Right so I ended up setting it as a service and calling it from the controller as and when it's needed.

Not sure if it's best practice but it works for me.

The service:

<?php

namespace AppBundle\FunBundle\Service;

class Latex
{

 public function __construct($twig)
    {
        $this->twig = $twig;
    }

public function escaper()
    {
        // Get twig env
        $twig = $this->twig;
        // Start setEscaper called 'latex' - call it what you want
        $twig->getExtension('Twig_Extension_Core')->setEscaper('latex',
            function($twig, $string, $charset){
            // Replace every instance of '&' with '\&'
            $string = str_replace("&", "\\&", $string);
            }
            return $string;
        );
    }
}

Then in app/config/services.yml:

services:
    app.latex:
        class: AppBundle\FunBundle\Service\Latex
        arguments: ['@twig']

Then in a controller action:

$latexer = $this->get('app.latex');
$latexer->escaper();

And in the twig template itself:

{% autoescape 'latex' %}
# latex/twig goes here
{% end autoescape %}

Ended up writing it up here on my site, which includes a full example of a LaTeX escaper.

Upvotes: 1

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