Feature/adding template filter for switch flag sample usable for if statement conditions

[MatthewEthanTam]

This PR is addressing #510, as the previous PR was out of sync

[MatthewEthanTam]

@ulgens Please see new PR rebased to master and removed updates to .po files.

[dancergraham]

question: should this be a register.filter like the switch and sample above and below ? context: I don't use django templates so apologies if I'm missing something obvious

[MatthewEthanTam]

Good question @dancergraham , so since there are more than 2 arguments with differing types for this function, we cannot use a template filter for it, therefore, we use a simple tag and set the variable in the django template.

{% flag_is_active "flag" request True as is_flag_active %}
{% if is_flag_active %}
  flag_is_active on
{% else %}
  flag_is_active off
{% endif %}

[MatthewEthanTam]

Sadly it is not as clean of an implementation, and there are forums about this exact issue dating back to 2007 (https://code.djangoproject.com/ticket/1199)

[ulgens]

@MatthewEthanTam I checked the PR and issue several times and I still don't understand the case here. I'll check it again when I have better availability. Sorry for the delay.

[MatthewEthanTam]

@ulgens Thank you for your time and no worries about the delay, I an happy to contribute!

There are two cases.

First, the case explained in the issue is where code is duplicated when a Switch and a context variable are needed to display text/ elements in an HTML block. The implementation will allow for cleaner HTML code and reduced lines of code.

Before implementation:

{% switch 'switch'%}
  {% if context_variable %}
    modified message
  {% else %}
    default message
  {% endif %}
{% else %}
  default message
{%endswitch%}

After implementation:

{% if 'switch'|switch_is_active and context_variable%}
  modified message
{% else %}
  default message
{% endif %}

Second, HTML linters/formatters such as DJLint do not recognize the {% switch 'switch_name' %} template tag, but do recognize {% if switch_is_active|'switch_name' %}, allowing for a better linting & formatting experience.

[clintonb]

Can you add documentation, please?

[dancergraham]

@MatthewEthanTam do you need any help putting together the documentation?