Liquid Basics

Liquid Template Syntax Basics

This is an introduction to the Spiffy Stores' Liquid template syntax, and a reference for Spiffy Stores-specific Tags and Filters.

Liquid is the templating engine for customizing your store layout. It's a small and fast template language which is quick and easy to learn but contains very powerful features for full customization.

Basics

There are two types of markup in liquid: Output and Tag.

• Output is surrounded by

   {{ two curly brackets }} 

• Tags are surrounded by

   {% a curly bracket and a percent %} 

Output blocks will always be replaced with the data which they reference.

For instance if your liquid template has a product object exposed to it you can print the name of the product to the screen by referencing

 {{ product.title }} 

Tags drive the logic of templates. They are responsible for loops and branching logic such as If / Else.

Output

Here is a simple example of Output:

Hello {{name}}
Hello {{user.name}}
Hello {{ 'fred' }}

Acceptable Tags and Comments

We sanitize all templates, so that you may not use javascript or tags that might be harmful to the application. Disallowed tags include, but aren’t limited to:

• HEAD
• BODY
• SCRIPT

Comments

HTML comments are automatically sanitized by our system. If you wish to place comments in your code, do it with a liquid comment, like so:

 {{ # This is a comment in liquid, and won't show up on the output }} 

Filters

Output markup takes filters. Filters are simple methods. The first parameter is always the output of the left side of the filter. The return value of the filter will be the new left value when the next filter is run. When there are no more filters the template will receive the resulting string.

Hello {{ 'fred' | upcase }}
Hello fred has {{ 'fred' | length }} letters!
Hello {{ '*fred*' | textilize | upcase }}
Hello {{ 'now' | date: "%Y %h" }}

Filter Reference

Add a list of filters here!!!

Tags

Tags are for the logic in your template. New tags are very easy to code and I hope to get many contributions to the standard tag library after releasing this code.

Here is a list of currently supported tags:

Comments

Comment is the simplest tag. It just swallows content.

Hi tobi {% comment %} you stink {% endcomment %}

If / Else

If else should be well known from any language imaginable. Liquid allows you to write simple expressions in the if.

{% if user %}
  Hi {{ user.name }}
{% endif %}

{% if user.name == 'tobi' %}
  hi tobi
{% endif %}

{% if user.name != 'tobi' %}
  hi non-tobi
{% endif %}

{% if user.creditcard == null %}
   poor sob
{% endif %}

{% if user.payments == empty %}
   you never paid !
{% endif %}

{% if user.age > 18 %}
   Login here
{% else %}
   Sorry, you are too young
{% endif %}

Case Statement

If you need more than one condition you can use the Case Statement

{% case condition %}
{% when 1 %}
hit 1
{% when 2 %}

hit 2
{% else %}
elseblock
{% endcase %}

Example:

{% case template %}
	
{% when 'label' %}
     // {{ label.title }}
{% when 'product' %}
     // {{ product.vendor | link_to_vendor }} / {{ product.title }}
{% else %}
     // {{page_title}
{% endcase %}

Cycle

Often you have to alternate between different colours for similar tasks. Liquid has build in support for such operations using the cycle tag.

{% cycle 'one', 'two', 'three' %}
{% cycle 'one', 'two', 'three' %}
{% cycle 'one', 'two', 'three' %}
{% cycle 'one', 'two', 'three' %}

will result in

one
two
three
one

If no name is supplied for the cycle group then its assumed that multiple calls with the same parameters are one group.

If you want to have total control over cycle groups you can optionally specify the name of the group. This can even be a variable.

{% cycle 'group 1': 'one', 'two', 'three' %}
{% cycle 'group 1': 'one', 'two', 'three' %}
{% cycle 'group 2': 'one', 'two', 'three' %}
{% cycle 'group 2': 'one', 'two', 'three' %}

will result in

one
two
one
two

For loops

Liquid allows for loops over collections

  {% for item in array %}
    {{ item }}
  {% endfor %}

During every for loop there are following helper variables available for extra styling needs:

 forloop.length       # => length of the entire for loop
 forloop.index	      # => index of the current iteration
 forloop.index0	      # => index of the current iteration (zero based)
 forloop.rindex       # => how many items are still left?
 forloop.rindex0      # => how many items are still left? (zero based)
 forloop.first	      # => is this the first iteration?
 forloop.last	      # => is this the last iteration?

There are several attributes you can use to influence which items you receive in your loop

limit lets you restrict how many items you get offset lets you start the collection with the nth item.

  # array = [1,2,3,4,5,6]
  {% for item in array limit:2 offset:2 %}
    {{ item }}
  {% endfor %}
  # results in 3,4

Instead of looping over an existing collection, you can define a range of numbers to loop through. The range can be defined by both literal and variable numbers:

  # if item.quantity is 4...
  {% for i in (1..item.quantity) %}
    {{ i }}
  {% endfor %}
  # results in 1,2,3,4

Tables

Liquid can create table rows and cells for you (you still need to wrap a table tag around the tablerow instruction):

  {% tablerow item in items cols: 3 limit: 12 %}
    {{ item.variable }}
  {% endtablerow %}

You can also find out whether a table cell is the first or last column in a row or directly query the column number:

 tablerowloop.length       # => length of the entire for loop
 tablerowloop.index	   # => index of the current iteration
 tablerowloop.index0	      # => index of the current iteration (zero based)
 tablerowloop.rindex       # => how many items are still left?
 tablerowloop.rindex0      # => how many items are still left? (zero based)
 tablerowloop.first	   # => is this the first iteration?
 tablerowloop.last	   # => is this the last iteration?
 tablerowloop.col	   # => index of column in the current row
 tablerowloop.col0	   # => index of column in the current row (zero based)
 tablerowloop.col_first    # => is this the first column in the row?
 tablerowloop.col_last     # => is this the last column in the row?

  {% tablerow item in items cols: 3 %}
    {% if col_first %}
      First column: {{ item.variable }}
    {% else %}
      Different column: {{ item.variable }}
    {% endif %}
  {% endtablerow %}

Variable Assignment

You can store data in your own variables, to be used in output or other tags as desired. The simplest way to create a variable is with the assign tag, which has a pretty straightforward syntax:

{% assign name = 'freestyle' %}
{% for t in collections.tags %}{% if t == name %}
  <p>Freestyle!</p>
{% endif %}{% endfor %}

Another way of doing this would be to assign true/false values to the variable:

{% assign freestyle = false %}
{% for t in collections.tags %}{% if t == 'freestyle' %}
  {% assign freestyle = true %}
{% endif %}{% endfor %}
{% if freestyle %}
  <p>Freestyle!</p>
{% endif %}

If you want to combine a number of strings into a single string and save it to a variable, you can do that with the capture tag. This tag is a block which "captures" whatever is rendered inside it and assigns it to the given variable instead of rendering it to the screen. Here's how it works:

  {% capture attribute_name %}{{ item.title | handleize }}-{{ i }}-color{% endcapture %}

  <label for="{{ attribute_name }}">Color:</label>
  <select name="attributes[{{ attribute_name }}]" id="{{ attribute_name }}">
    <option value="red">Red</option>
    <option value="green">Green</option>
    <option value="blue">Blue</option>
  </select>