Twig for template designers (UP)-twig User Guide

1. Overview

The template is a simple text file. It can generate any text-based format (HTML, XML, CSV, and so on). It does not have a specific extension, HTML or XML is OK. A variable or expression contained in a template that controls the logic of a template. When templates are preprocessed, they are replaced with variable values.

The following is a minimal template that illustrates some of the basic elements. We'll cover more details later:

<! DOCTYPE html>
　　
Twig has two types of separators: {% ... %} and {{...}}. The first is a control statement that executes such as a For loop, which prints the result of an expression in the template.
2. IDEs Integration
Many IDES support twig syntax highlighting and auto-completion tags:
※textmate via Twig Bundle
※vim via Jinja Syntax plugin or Vim-twig plugin
※netbeans via Twig Syntax plug-in (7.2+)
※phpstorm (native 2.1+)
※eclipse through Twig plugin
※sublime via Twig Bundle
※gtksourceview through Twig language definition
※coda and SubEthaEdit via Twig syntax mode
※coda 2 via other Twig syntax mode
※komodo and Komodo Edit via Twig highlight/syntax check mode
※notepad++ through notepad++ Twig highlighter
※emacs through Web-mode.el
3. Variables
The application passes the variable to the template of the operation. You can also access the properties or elements of a variable. The visual representation of a variable depends to a large extent on the value provided by the application. You can use the dot (.) Or the so-called Under-Banner method ([]) to access the properties of a variable (PHP object's method or property, the elements of the PHP array).
{{Foo.bar}} {{foo[' bar '}}
When the attribute contains special characters (such as-this is interpreted as the minus operator), use the attribute () function instead of the point of Use (.). To access variable properties:
{# equivalent to the non-working Foo.data-foo #} {{attribute (foo, ' Data-foo ')}}
Important: Be aware that curly braces are not part of a variable, except for print statements. When accessing variables within a tag, do not add braces to the variable.
If a variable or property does not exist, you will receive a null value when the Strict_variables option is set to False, and an error will be thrown if Strict_variables is set to True,twig (see environment Options
Variable invocation mechanism
For the sake of convenience, when invoking foo.bar in the PHP presentation layer, the following actions are performed:
A.1 checks if Foo is an array and checks if bar is a valid element A.2 if not, Foo is an object and checks if bar is a valid property a.3 if not, Foo is an object and checks if bar is a valid method. (Even if bar is a constructor.) Then use the __construct () method instead of A.4 if it is not, Foo is an object that checks whether Getbar () is a valid method a.5 if not, Foo is an object that checks whether Isbar () is a valid method a.6 if not, returns a null value (NULL) A.7 Check foo is an array and bar is a valid element; A.8 if not, a null value is returned.
4. Global variables
The following variables are always available in the template:
_self: referencing the current template;
_context: Refers to the current context;
_charset: Refers to the current character set.
5. Setting variables
You can assign a value to a variable in an internal code block. Assigning values using the SET tag:
{% Set foo = ' foo '%} {% Set foo = [1, 2]%} {% Set foo = {' foo ': ' Bar '}%}
　　
6. Filter
Variables can be modified through the filter. Use pipe symbols (i.e. vertical bars |) between filters and variables Separated, there may be optional parameters in the filter brackets. Multiple filters can be used in a concatenation, and the output of the filter is applied to the next filter.
The following example removes all HTML tags from the name and applies title-cases formatting:
{{Name|striptags|title}}
The filter accepts the arguments in parentheses. This example will concatenate a list with commas:
{{List|join (', ')}}
To apply a filter to a piece of code, simply wrap it up with the filter tag:
{% filter upper%}    This text becomes uppercase{% endfilter%}
　　
Visit the Filters page to learn more about the built-in filters.
7. Functions
Functions can be called to generate content. Functions are called through their [function name + ()] and may also have parameters.
For example, the range () function returns a list that contains an integer arithmetic progression:
{% for I in range (0, 3)%}    {{i}},{% endfor%}
　　
Visit the Functions page to learn more about built-in functions.
8. Named parameters
1.12 New features: support for named parameters is added to twig version 1.12.
{% for I in range (Low=1, high=10, step=2)%}    {{i}},{% endfor%}
Use named parameters to give your template a clearer understanding of the meaning of the values you pass as parameters:
{{data|convert_encoding (' UTF-8 ', ' ISO-2022-JP ')}} {# versus (contrast) #} {{data|convert_encoding (from= ' iso-2022-jp ', to= ' UTF-8 ')}}
Named parameters also allow you to skip some parameters that you do not want to change the default values for:
{# The first argument is the date format, which defaults to the global date format if NULL is passed #} {"Now" |date (null, "Europe/paris")}} {# or skip the format value by using a named argument for the time zone #} {"Now" |date (timezone= "Europe/paris")}}
You can also use placeholder parameters and named parameters in a call, in which case the placeholder parameter must precede the named parameter:
{"Now" |date (' d/m/y h:i ', timezone= "Europe/paris")}}
　　
Tip: Each function and filter's document page has a section that lists all of the parameter names that they support.
9. Control structure
A control structure refers to the code for all of these control procedures: conditional statements (such as: If/elseif/else), for loops, and similar blocks of code. Control structure appears in {% ... %} within the block.
For example, to display a list of users provided by the variable (users), use the for label:
The IF tag can be used to test an expression:
{% if users|length > 0}    <ul>        {% for user in users%}            <li>{{user.username|e}}</li>        {% endfor%}    </ul>{ % ENDIF%}
Visit the tags page to learn more about the built-in labels.
10. Notes
To comment out a portion of the template, use the comment syntax {#...#}. This is useful for debugging or adding information to other template designers or for your own viewing:
{# note:disabled template because we no longer    use this {% for user in users%}        ...    {% ENDfor%}#}
　　
11. Include Other templates
When you include a template, the include tag is useful, and it returns the contents of the template (the child templates) to the current stencil (parent template):
{% include ' sidebar.html '%}
By default, each contained template is passed the current context. The context passed to the parent template and also includes variables defined in the child template:
{% for box in boxes%}    {% include "render_box.html"%} {% ENDFOR%}
　　
The included template render_box.html is able to access the variable box.
The file name of the template depends on the template loader. For example, Twig_loader_filesystem allows you to access other templates by giving them a file name. You can access the templates in the sub-directories separated by a slash:
{% include "sections/articles/sidebar.html"%}
This behavior depends on embedding twig in the application.
Twig for template designers (UP)-twig User Guide