Variables and templating

Variables

You can declare a variable in one of the following ways:

• pass it in the settings when building documentation;
• describe it in the variable presets file.

Below are the options for using variables in a document.

Substitutions

To substitute a variable value into text, enclose its name on both sides with double curly braces.

Какой-то текст {{ имя_переменной }} продолжение текста.

If the text contains double curly braces but does not imply variable substitution, add not_var before the construct.

Какой-то текст not_var{{ тоже_текст }} продолжение текста.

Conditional operators

You can use the conditional operators if, else, and elsif to include specific text fragments in a document depending on variable values. For example, to build two versions of a document for different operating systems.

{% if  OS == 'iOS' %}

Скачайте приложение в [App Store](https://www.apple.com/ios/app-store/).

{% else %}

Скачайте приложение в [Google Play](https://play.google.com).

{% endif %}

Conditional operators can be applied not only to text blocks but also to text fragments within lines.

Какой-то текст {% if  OS == 'iOS' %} Apple {% else %} Android {% endif %} продолжение текста.

Supported constructs

Comparison operators: == , != , > , < , >= , <=

Logical operators: and , or

The contains operator:

• for string A, checks that it contains substring B

  {% if Object.title contains 'API' %}
  
• for array A, checks that it contains element B

  {% if keywords contains 'Extension' %}
  

Loops

Use loops to output repeated content for each element of an array. Inside a loop, refer to an element as a regular variable using the syntax for substitution.

{% for имя_переменной in имя_массива %}

Какой-то текст {{ имя_переменной }} продолжение текста.

{% endfor %}

default:
  users:
    - Alice
    - Mark

Prefix {% for user in users %} {{user}} {% endfor %} Postfix

Prefix

{% for user in users %}

{{user}}

{% endfor %}

Postfix

Filters

To apply a filter, add the operator | and the filter name to the variable. The operator is separated by spaces on both sides.

default:
  user:
    name: alice
  users:
    - Alice
    - Mark

Hello {{ user.name | capitalize }}!

{{ users | length }}

{{ user.name | length }} | length

Functions

To call a function, add the character . to the variable, specify its name, and pass the required parameters in parentheses ().

The function slice(beginIndex, endIndex) returns the specified part of the original array as a new array object.
Parameters:

• beginIndex — the index of the element from which the extraction starts (numbering starts at 0).
• endIndex— the index of the element at which the extraction ends (numbering starts at 0).
  If the parameter is not specified, all elements from the starting position to the end of the array are selected.

default:
  user:
    name: Masha

Hello P{{ user.name.slice(1) }}!

Hello P{{ user.name.slice(1, 2) }}vel!