Template::Liquid::Tag::For - Simple loop construct
{% for x in (1..10) %} x = {{ x }} {% endfor %}
For loops... uh, loop over collections.
During every for loop, the following helper variables are 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 iternation?
forloop.type
are we looping through an ARRAY or a HASH?
ARRAY
HASH
There are several attributes you can use to influence which items you receive in your loop:
limit:int
lets you restrict how many items you get.
offset:int
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
You can reverse the direction the loop works with the reversed attribute. To comply with the Ruby lib's functionality, reversed must be the first attribute.
reversed
{% for item in collection reversed %} {{item}} {% endfor %}
You can sort the variable with the sorted attribute. This is an extention beyond the scope of Liquid's syntax and thus incompatible but it's useful. The
sorted
{% for item in collection sorted %} {{item}} {% endfor %}
If you are sorting a hash, the values are sorted by keys by default. You may decide to sort by values like so:
{% for item in hash sorted:value %} {{item.value}} {% endfor %}
...or make the default obvious with...
{% for item in hash sorted:key %} {{item.key}} {% endfor %}
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
To deal with the possibility of looping through hash references, Solution extends the Liquid Engine's functionality. When looping through a hash, each item is made a single key/value pair. The item's actual key and value are in the item.key and item.value variables. ...here's an example:
item.key
item.value
# where var = {A => 1, B => 2, C => 3} { {% for x in var %} {{ x.key }} => {{ x.value }}, {% endfor %} } # results in { A => 1, C => 3, B => 2, }
The forloop.type variable will contain HASH if the looped variable is a hashref. Also note that the keys/value pairs are left unsorted.
else
The else tag allows us to do this:
{% for item in collection %} Item {{ forloop.index }}: {{ item.name }} {% else %} There is nothing in the collection. {% endfor %}
The else branch is executed whenever the for branch will never be executed (e.g. collection is blank or not an iterable or out of iteration scope).
Since this is a customer facing template engine, Liquid should provide some way to limit ranges and/or depth to avoid (functionally) infinite loops with code like...
{% for w in (1..10000000000) %} {% for x in (1..10000000000) %} {% for y in (1..10000000000) %} {% for z in (1..10000000000) %} {{ 'own' | replace:'o','p' }} {%endfor%} {%endfor%} {%endfor%} {%endfor%}
Liquid for Designers: http://wiki.github.com/tobi/liquid/liquid-for-designers
Template::Liquid's docs on custom filter creation
Template::Liquid::Tag::Break and Template::Liquid::Tag::Continue
Sanko Robinson <sanko@cpan.org> - http://sankorobinson.com/
CPAN ID: SANKO
Copyright (C) 2009-2012 by Sanko Robinson <sanko@cpan.org>
This program is free software; you can redistribute it and/or modify it under the terms of The Artistic License 2.0. See the LICENSE file included with this distribution or notes on the Artistic License 2.0 for clarification.
When separated from the distribution, all original POD documentation is covered by the Creative Commons Attribution-Share Alike 3.0 License. See the clarification of the CCA-SA3.0.
To install Template::Liquid, copy and paste the appropriate command in to your terminal.
cpanm
cpanm Template::Liquid
CPAN shell
perl -MCPAN -e shell install Template::Liquid
For more information on module installation, please visit the detailed CPAN module installation guide.