How to var_dump variables in twig templates?

Question

View layer pattern where you only present what you have been given is fine and all, but how do you know what is available? Is there a \"list all defined variables\" function

Answer 1

So I got it working, partly a bit hackish:

1. Set twig: debug: 1 in app/config/config.yml

2. Add this to config_dev.yml

   services:
       debug.twig.extension:
           class: Twig_Extensions_Extension_Debug
           tags: [{ name: 'twig.extension' }]
   

3. sudo rm -fr app/cache/dev

4. To use my own debug function instead of print_r(), I opened vendor/twig-extensions/lib/Twig/Extensions/Node/Debug.php and changed print_r( to d(

PS. I would still like to know how/where to grab the $twig environment to add filters and extensions.