Question

I see alot of {{#variable}} and {{/variable}} used in PHP code. Most specifically in MVC and Mustache templated apps. I’ve also seen {{^variable}} and {{/variable}} used. What are they, and more importantly what are they used for?

Answer 1

This is Mustache templating. You can read the docs for it here.

{{#variable}} and {{/variable}}: Section

Sections render blocks of text one or more times, depending on the
value of the key in the current context.

A section begins with a pound and ends with a slash. That is,
{{#person}} begins a “person” section while {{/person}} ends it.

False Values or Empty Lists

If the person key exists and has a value of false or an empty list,
the HTML between the pound and slash will not be displayed.

Template:

Shown. 
{{#nothin}}   
  Never shown! 
{{/nothin}}

Hash:

{   
    "person": true, 
}

Output:

Shown.

{{^variable}} and {{/variable}}: Inverted Section

An inverted section begins with a caret (hat) and ends with a slash.
That is {{^person}} begins a “person” inverted section while
{{/person}} ends it.

While sections can be used to render text one or more times based on
the value of the key, inverted sections may render text once based on
the inverse value of the key. That is, they will be rendered if the
key doesn’t exist, is false, or is an empty list.