1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474 475 476 477 478 479 480 481 482 483 484 485 486 487 488 489 490 491 492 493 494 495 496 497 498 499 500 501 502 503 504 505 506 507 508 509 510 511 512 513 514 515 516 517 518 519 520 521 522 523 524 525 526 527 528 529 530 531 532 533 534 535 536 537 538 539 540 541 542 543 544 545 546 547 548 549 550 551 552 553 554 555 556 557 558 559 560 561 562 563 564 565 566 567 568 569 570 571 572 573 574 575 576 577 578 579 580 581 582 583 584 585 586 587 588 589 590 591 592 593 594 595 596 597 598 599 600 601 602 603 604 605 606 607 608 609 610 611 612 613 614 615 616 617 618 619 620 621 622 623 624 625 626 627 628 629 630 631 632 633 634 635 636 637 638 639 640 641 642 643 644 645 646 647 648 649 650 651 652 653 654 655 656 657 658 659 660 661 662 663 664 665 666 667 668 669 670 671 672 673 674 675 676 677 678 679 680 681 682 683 684 685 686 687 688 689 690 691 692 693 694 695 696 697 698 699 700 701 702 703 704 705 706 707 708 709 710 711 712 713 714 715 716 717 718 719 720 721 722 723 724 725 726 727 728 729 730 731 732 733 734 735 736 737 738 739 740 741 742 743 744 745 746 747 748 749 750 751 752 753 754 755 756 757 758 759 760 761 762 763 764 765 766 767 768 769 770 771 772 773 774 775 776 777 778 779 780 781 782 783 784 785 786 787 788 789 790 791 792 793 794 795 796 797 798 799 800 801 802 803 804 805 806 807 808 809 810 811 812 813 814 815 816 817 818 819 820 821 822 823 824 825 826 827 828 829 830 831 832 833 834 835 836 837 838 839 840 841 842 843 844 845 846 847 848 849 850 851 852 853 854 855 856 857 858 859 860 861 862 863 864 865 866 867 868 869 870 871
|
Twig for Template Designers
===========================
This document describes the syntax and semantics of the template engine and
will be most useful as reference to those creating Twig templates.
Synopsis
--------
A template is a regular text file. It can generate any text-based format (HTML,
XML, CSV, LaTeX, etc.). It doesn't have a specific extension, ``.html`` or
``.xml`` are just fine.
A template contains **variables** or **expressions**, which get replaced with
values when the template is evaluated, and **tags**, which control the
template's logic.
Below is a minimal template that illustrates a few basics. We will cover further
details later on:
.. code-block:: html+twig
<!DOCTYPE html>
<html>
<head>
<title>My Webpage</title>
</head>
<body>
<ul id="navigation">
{% for item in navigation %}
<li><a href="{{ item.href }}">{{ item.caption }}</a></li>
{% endfor %}
</ul>
<h1>My Webpage</h1>
{{ a_variable }}
</body>
</html>
There are two kinds of delimiters: ``{% ... %}`` and ``{{ ... }}``. The first
one is used to execute statements such as for-loops, the latter outputs the
result of an expression.
IDEs Integration
----------------
Many IDEs support syntax highlighting and auto-completion for Twig:
* *Textmate* via the `Twig bundle`_
* *Vim* via the `Jinja syntax plugin`_ or the `vim-twig plugin`_
* *Netbeans* via the `Twig syntax plugin`_ (until 7.1, native as of 7.2)
* *PhpStorm* (native as of 2.1)
* *Eclipse* via the `Twig plugin`_
* *Sublime Text* via the `Twig bundle`_
* *GtkSourceView* via the `Twig language definition`_ (used by gedit and other projects)
* *Coda* and *SubEthaEdit* via the `Twig syntax mode`_
* *Coda 2* via the `other Twig syntax mode`_
* *Komodo* and *Komodo Edit* via the Twig highlight/syntax check mode
* *Notepad++* via the `Notepad++ Twig Highlighter`_
* *Emacs* via `web-mode.el`_
* *Atom* via the `PHP-twig for atom`_
* *Visual Studio Code* via the `Twig pack`_
Also, `TwigFiddle`_ is an online service that allows you to execute Twig templates
from a browser; it supports all versions of Twig.
Variables
---------
The application passes variables to the templates for manipulation in the
template. Variables may have attributes or elements you can access, too. The
visual representation of a variable depends heavily on the application providing
it.
Use a dot (``.``) to access attributes of a variable (methods or properties of a
PHP object, or items of a PHP array):
.. code-block:: twig
{{ foo.bar }}
.. note::
It's important to know that the curly braces are *not* part of the
variable but the print statement. When accessing variables inside tags,
don't put the braces around them.
.. sidebar:: Implementation
For convenience's sake ``foo.bar`` does the following things on the PHP
layer:
* check if ``foo`` is an array and ``bar`` a valid element;
* if not, and if ``foo`` is an object, check that ``bar`` is a valid property;
* if not, and if ``foo`` is an object, check that ``bar`` is a valid method
(even if ``bar`` is the constructor - use ``__construct()`` instead);
* if not, and if ``foo`` is an object, check that ``getBar`` is a valid method;
* if not, and if ``foo`` is an object, check that ``isBar`` is a valid method;
* if not, and if ``foo`` is an object, check that ``hasBar`` is a valid method;
* if not, return a ``null`` value.
Twig also supports a specific syntax for accessing items on PHP arrays,
``foo['bar']``:
* check if ``foo`` is an array and ``bar`` a valid element;
* if not, return a ``null`` value.
If a variable or attribute does not exist, you will receive a ``null`` value
when the ``strict_variables`` option is set to ``false``; alternatively, if ``strict_variables``
is set, Twig will throw an error (see :ref:`environment options<environment_options>`).
.. note::
If you want to access a dynamic attribute of a variable, use the
:doc:`attribute<functions/attribute>` function instead.
The ``attribute`` function is also useful when the attribute contains
special characters (like ``-`` that would be interpreted as the minus
operator):
.. code-block:: twig
{# equivalent to the non-working foo.data-foo #}
{{ attribute(foo, 'data-foo') }}
Global Variables
~~~~~~~~~~~~~~~~
The following variables are always available in templates:
* ``_self``: references the current template name;
* ``_context``: references the current context;
* ``_charset``: references the current charset.
Setting Variables
~~~~~~~~~~~~~~~~~
You can assign values to variables inside code blocks. Assignments use the
:doc:`set<tags/set>` tag:
.. code-block:: twig
{% set foo = 'foo' %}
{% set foo = [1, 2] %}
{% set foo = {'foo': 'bar'} %}
Filters
-------
Variables can be modified by **filters**. Filters are separated from the
variable by a pipe symbol (``|``). Multiple filters can be chained. The output
of one filter is applied to the next.
The following example removes all HTML tags from the ``name`` and title-cases
it:
.. code-block:: twig
{{ name|striptags|title }}
Filters that accept arguments have parentheses around the arguments. This
example joins the elements of a list by commas:
.. code-block:: twig
{{ list|join(', ') }}
To apply a filter on a section of code, wrap it with the
:doc:`apply<tags/apply>` tag:
.. code-block:: twig
{% apply upper %}
This text becomes uppercase
{% endapply %}
Go to the :doc:`filters<filters/index>` page to learn more about built-in
filters.
.. note::
The ``apply`` tag was introduced in Twig 2.9; use the ``filter`` tag with
previous versions.
Functions
---------
Functions can be called to generate content. Functions are called by their
name followed by parentheses (``()``) and may have arguments.
For instance, the ``range`` function returns a list containing an arithmetic
progression of integers:
.. code-block:: twig
{% for i in range(0, 3) %}
{{ i }},
{% endfor %}
Go to the :doc:`functions<functions/index>` page to learn more about the
built-in functions.
.. _named-arguments:
Named Arguments
---------------
.. code-block:: twig
{% for i in range(low=1, high=10, step=2) %}
{{ i }},
{% endfor %}
Using named arguments makes your templates more explicit about the meaning of
the values you pass as arguments:
.. code-block:: twig
{{ data|convert_encoding('UTF-8', 'iso-2022-jp') }}
{# versus #}
{{ data|convert_encoding(from='iso-2022-jp', to='UTF-8') }}
Named arguments also allow you to skip some arguments for which you don't want
to change the default value:
.. code-block:: twig
{# 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 both positional and named arguments in one call, in which
case positional arguments must always come before named arguments:
.. code-block:: twig
{{ "now"|date('d/m/Y H:i', timezone="Europe/Paris") }}
.. tip::
Each function and filter documentation page has a section where the names
of all arguments are listed when supported.
Control Structure
-----------------
A control structure refers to all those things that control the flow of a
program - conditionals (i.e. ``if``/``elseif``/``else``), ``for``-loops, as
well as things like blocks. Control structures appear inside ``{% ... %}``
blocks.
For example, to display a list of users provided in a variable called
``users``, use the :doc:`for<tags/for>` tag:
.. code-block:: html+twig
<h1>Members</h1>
<ul>
{% for user in users %}
<li>{{ user.username|e }}</li>
{% endfor %}
</ul>
The :doc:`if<tags/if>` tag can be used to test an expression:
.. code-block:: html+twig
{% if users|length > 0 %}
<ul>
{% for user in users %}
<li>{{ user.username|e }}</li>
{% endfor %}
</ul>
{% endif %}
Go to the :doc:`tags<tags/index>` page to learn more about the built-in tags.
Comments
--------
To comment-out part of a line in a template, use the comment syntax ``{# ...
#}``. This is useful for debugging or to add information for other template
designers or yourself:
.. code-block:: twig
{# note: disabled template because we no longer use this
{% for user in users %}
...
{% endfor %}
#}
Including other Templates
-------------------------
The :doc:`include<functions/include>` function is useful to include a template
and return the rendered content of that template into the current one:
.. code-block:: twig
{{ include('sidebar.html') }}
By default, included templates have access to the same context as the template
which includes them. This means that any variable defined in the main template
will be available in the included template too:
.. code-block:: twig
{% for box in boxes %}
{{ include('render_box.html') }}
{% endfor %}
The included template ``render_box.html`` is able to access the ``box`` variable.
The name of the template depends on the template loader. For instance, the
``\Twig\Loader\FilesystemLoader`` allows you to access other templates by giving the
filename. You can access templates in subdirectories with a slash:
.. code-block:: twig
{{ include('sections/articles/sidebar.html') }}
This behavior depends on the application embedding Twig.
Template Inheritance
--------------------
The most powerful part of Twig is template inheritance. Template inheritance
allows you to build a base "skeleton" template that contains all the common
elements of your site and defines **blocks** that child templates can
override.
It's easier to understand the concept by starting with an example.
Let's define a base template, ``base.html``, which defines an HTML skeleton
document that might be used for a two-column page:
.. code-block:: html+twig
<!DOCTYPE html>
<html>
<head>
{% block head %}
<link rel="stylesheet" href="style.css"/>
<title>{% block title %}{% endblock %} - My Webpage</title>
{% endblock %}
</head>
<body>
<div id="content">{% block content %}{% endblock %}</div>
<div id="footer">
{% block footer %}
© Copyright 2011 by <a href="http://domain.invalid/">you</a>.
{% endblock %}
</div>
</body>
</html>
In this example, the :doc:`block<tags/block>` tags define four blocks that
child templates can fill in. All the ``block`` tag does is to tell the
template engine that a child template may override those portions of the
template.
A child template might look like this:
.. code-block:: html+twig
{% extends "base.html" %}
{% block title %}Index{% endblock %}
{% block head %}
{{ parent() }}
<style type="text/css">
.important { color: #336699; }
</style>
{% endblock %}
{% block content %}
<h1>Index</h1>
<p class="important">
Welcome to my awesome homepage.
</p>
{% endblock %}
The :doc:`extends<tags/extends>` tag is the key here. It tells the template
engine that this template "extends" another template. When the template system
evaluates this template, first it locates the parent. The extends tag should
be the first tag in the template.
Note that since the child template doesn't define the ``footer`` block, the
value from the parent template is used instead.
It's possible to render the contents of the parent block by using the
:doc:`parent<functions/parent>` function. This gives back the results of the
parent block:
.. code-block:: html+twig
{% block sidebar %}
<h3>Table Of Contents</h3>
...
{{ parent() }}
{% endblock %}
.. tip::
The documentation page for the :doc:`extends<tags/extends>` tag describes
more advanced features like block nesting, scope, dynamic inheritance, and
conditional inheritance.
.. note::
Twig also supports multiple inheritance via "horizontal reuse" with the help
of the :doc:`use<tags/use>` tag.
HTML Escaping
-------------
When generating HTML from templates, there's always a risk that a variable
will include characters that affect the resulting HTML. There are two
approaches: manually escaping each variable or automatically escaping
everything by default.
Twig supports both, automatic escaping is enabled by default.
The automatic escaping strategy can be configured via the
:ref:`autoescape<environment_options>` option and defaults to ``html``.
Working with Manual Escaping
~~~~~~~~~~~~~~~~~~~~~~~~~~~~
If manual escaping is enabled, it is **your** responsibility to escape variables
if needed. What to escape? Any variable that comes from an untrusted source.
Escaping works by using the :doc:`escape<filters/escape>` or ``e`` filter:
.. code-block:: twig
{{ user.username|e }}
By default, the ``escape`` filter uses the ``html`` strategy, but depending on
the escaping context, you might want to explicitly use an other strategy:
.. code-block:: twig
{{ user.username|e('js') }}
{{ user.username|e('css') }}
{{ user.username|e('url') }}
{{ user.username|e('html_attr') }}
Working with Automatic Escaping
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Whether automatic escaping is enabled or not, you can mark a section of a
template to be escaped or not by using the :doc:`autoescape<tags/autoescape>`
tag:
.. code-block:: twig
{% autoescape %}
Everything will be automatically escaped in this block (using the HTML strategy)
{% endautoescape %}
By default, auto-escaping uses the ``html`` escaping strategy. If you output
variables in other contexts, you need to explicitly escape them with the
appropriate escaping strategy:
.. code-block:: twig
{% autoescape 'js' %}
Everything will be automatically escaped in this block (using the JS strategy)
{% endautoescape %}
Escaping
--------
It is sometimes desirable or even necessary to have Twig ignore parts it would
otherwise handle as variables or blocks. For example if the default syntax is
used and you want to use ``{{`` as raw string in the template and not start a
variable you have to use a trick.
The easiest way is to output the variable delimiter (``{{``) by using a variable
expression:
.. code-block:: twig
{{ '{{' }}
For bigger sections it makes sense to mark a block
:doc:`verbatim<tags/verbatim>`.
Macros
------
Macros are comparable with functions in regular programming languages. They are
useful to reuse HTML fragments to not repeat yourself. They are described in the
:doc:`macro<tags/macro>` tag documentation.
.. _twig-expressions:
Expressions
-----------
Twig allows expressions everywhere.
.. note::
The operator precedence is as follows, with the lowest-precedence operators
listed first: ``?:`` (ternary operator), ``b-and``, ``b-xor``, ``b-or``,
``or``, ``and``, ``==``, ``!=``, ``<=>``, ``<``, ``>``, ``>=``, ``<=``,
``in``, ``matches``, ``starts with``, ``ends with``, ``..``, ``+``, ``-``,
``~``, ``*``, ``/``, ``//``, ``%``, ``is`` (tests), ``**``, ``??``, ``|``
(filters), ``[]``, and ``.``:
.. code-block:: twig
{% set greeting = 'Hello ' %}
{% set name = 'Fabien' %}
{{ greeting ~ name|lower }} {# Hello fabien #}
{# use parenthesis to change precedence #}
{{ (greeting ~ name)|lower }} {# hello fabien #}
Literals
~~~~~~~~
The simplest form of expressions are literals. Literals are representations
for PHP types such as strings, numbers, and arrays. The following literals
exist:
* ``"Hello World"``: Everything between two double or single quotes is a
string. They are useful whenever you need a string in the template (for
example as arguments to function calls, filters or just to extend or include
a template). A string can contain a delimiter if it is preceded by a
backslash (``\``) -- like in ``'It\'s good'``. If the string contains a
backslash (e.g. ``'c:\Program Files'``) escape it by doubling it
(e.g. ``'c:\\Program Files'``).
* ``42`` / ``42.23``: Integers and floating point numbers are created by
writing the number down. If a dot is present the number is a float,
otherwise an integer.
* ``["foo", "bar"]``: Arrays are defined by a sequence of expressions
separated by a comma (``,``) and wrapped with squared brackets (``[]``).
* ``{"foo": "bar"}``: Hashes are defined by a list of keys and values
separated by a comma (``,``) and wrapped with curly braces (``{}``):
.. code-block:: twig
{# keys as string #}
{ 'foo': 'foo', 'bar': 'bar' }
{# keys as names (equivalent to the previous hash) #}
{ foo: 'foo', bar: 'bar' }
{# keys as integer #}
{ 2: 'foo', 4: 'bar' }
{# keys can be omitted if it is the same as the variable name #}
{ foo }
{# is equivalent to the following #}
{ 'foo': foo }
{# keys as expressions (the expression must be enclosed into parentheses) #}
{% set foo = 'foo' %}
{ (foo): 'foo', (1 + 1): 'bar', (foo ~ 'b'): 'baz' }
* ``true`` / ``false``: ``true`` represents the true value, ``false``
represents the false value.
* ``null``: ``null`` represents no specific value. This is the value returned
when a variable does not exist. ``none`` is an alias for ``null``.
Arrays and hashes can be nested:
.. code-block:: twig
{% set foo = [1, {"foo": "bar"}] %}
.. tip::
Using double-quoted or single-quoted strings has no impact on performance
but :ref:`string interpolation <templates-string-interpolation>` is only
supported in double-quoted strings.
Math
~~~~
Twig allows you to do math in templates; the following operators are supported:
* ``+``: Adds two numbers together (the operands are casted to numbers). ``{{
1 + 1 }}`` is ``2``.
* ``-``: Subtracts the second number from the first one. ``{{ 3 - 2 }}`` is
``1``.
* ``/``: Divides two numbers. The returned value will be a floating point
number. ``{{ 1 / 2 }}`` is ``{{ 0.5 }}``.
* ``%``: Calculates the remainder of an integer division. ``{{ 11 % 7 }}`` is
``4``.
* ``//``: Divides two numbers and returns the floored integer result. ``{{ 20
// 7 }}`` is ``2``, ``{{ -20 // 7 }}`` is ``-3`` (this is just syntactic
sugar for the :doc:`round<filters/round>` filter).
* ``*``: Multiplies the left operand with the right one. ``{{ 2 * 2 }}`` would
return ``4``.
* ``**``: Raises the left operand to the power of the right operand. ``{{ 2 **
3 }}`` would return ``8``.
.. _template_logic:
Logic
~~~~~
You can combine multiple expressions with the following operators:
* ``and``: Returns true if the left and the right operands are both true.
* ``or``: Returns true if the left or the right operand is true.
* ``not``: Negates a statement.
* ``(expr)``: Groups an expression.
.. note::
Twig also supports bitwise operators (``b-and``, ``b-xor``, and ``b-or``).
.. note::
Operators are case sensitive.
Comparisons
~~~~~~~~~~~
The following comparison operators are supported in any expression: ``==``,
``!=``, ``<``, ``>``, ``>=``, and ``<=``.
You can also check if a string ``starts with`` or ``ends with`` another
string:
.. code-block:: twig
{% if 'Fabien' starts with 'F' %}
{% endif %}
{% if 'Fabien' ends with 'n' %}
{% endif %}
.. note::
For complex string comparisons, the ``matches`` operator allows you to use
`regular expressions`_:
.. code-block:: twig
{% if phone matches '/^[\\d\\.]+$/' %}
{% endif %}
Containment Operator
~~~~~~~~~~~~~~~~~~~~
The ``in`` operator performs containment test. It returns ``true`` if the left
operand is contained in the right:
.. code-block:: twig
{# returns true #}
{{ 1 in [1, 2, 3] }}
{{ 'cd' in 'abcde' }}
.. tip::
You can use this filter to perform a containment test on strings, arrays,
or objects implementing the ``Traversable`` interface.
To perform a negative test, use the ``not in`` operator:
.. code-block:: twig
{% if 1 not in [1, 2, 3] %}
{# is equivalent to #}
{% if not (1 in [1, 2, 3]) %}
Test Operator
~~~~~~~~~~~~~
The ``is`` operator performs tests. Tests can be used to test a variable against
a common expression. The right operand is name of the test:
.. code-block:: twig
{# find out if a variable is odd #}
{{ name is odd }}
Tests can accept arguments too:
.. code-block:: twig
{% if post.status is constant('Post::PUBLISHED') %}
Tests can be negated by using the ``is not`` operator:
.. code-block:: twig
{% if post.status is not constant('Post::PUBLISHED') %}
{# is equivalent to #}
{% if not (post.status is constant('Post::PUBLISHED')) %}
Go to the :doc:`tests<tests/index>` page to learn more about the built-in
tests.
Other Operators
~~~~~~~~~~~~~~~
The following operators don't fit into any of the other categories:
* ``|``: Applies a filter.
* ``..``: Creates a sequence based on the operand before and after the operator
(this is syntactic sugar for the :doc:`range<functions/range>` function):
.. code-block:: twig
{{ 1..5 }}
{# equivalent to #}
{{ range(1, 5) }}
Note that you must use parentheses when combining it with the filter operator
due to the :ref:`operator precedence rules <twig-expressions>`:
.. code-block:: twig
(1..5)|join(', ')
* ``~``: Converts all operands into strings and concatenates them. ``{{ "Hello
" ~ name ~ "!" }}`` would return (assuming ``name`` is ``'John'``) ``Hello
John!``.
* ``.``, ``[]``: Gets an attribute of a variable.
* ``?:``: The ternary operator:
.. code-block:: twig
{{ foo ? 'yes' : 'no' }}
{{ foo ?: 'no' }} is the same as {{ foo ? foo : 'no' }}
{{ foo ? 'yes' }} is the same as {{ foo ? 'yes' : '' }}
* ``??``: The null-coalescing operator:
.. code-block:: twig
{# returns the value of foo if it is defined and not null, 'no' otherwise #}
{{ foo ?? 'no' }}
.. _templates-string-interpolation:
String Interpolation
~~~~~~~~~~~~~~~~~~~~
String interpolation (``#{expression}``) allows any valid expression to appear
within a *double-quoted string*. The result of evaluating that expression is
inserted into the string:
.. code-block:: twig
{{ "foo #{bar} baz" }}
{{ "foo #{1 + 2} baz" }}
.. _templates-whitespace-control:
Whitespace Control
------------------
.. versionadded:: 2.8
Tag level line whitespace control was added in Twig 2.8.
The first newline after a template tag is removed automatically (like in PHP).
Whitespace is not further modified by the template engine, so each whitespace
(spaces, tabs, newlines etc.) is returned unchanged.
You can also control whitespace on a per tag level. By using the whitespace
control modifiers on your tags, you can trim leading and or trailing whitespace.
Twig supports two modifiers:
* *Whitespace trimming* via the ``-`` modifier: Removes all whitespace
(including newlines);
* *Line whitespace trimming* via the ``~`` modifier: Removes all whitespace
(excluding newlines). Using this modifier on the right disables the default
removal of the first newline inherited from PHP.
The modifiers can be used on either side of the tags like in ``{%-`` or ``-%}``
and they consume all whitespace for that side of the tag. It is possible to use
the modifiers on one side of a tag or on both sides:
.. code-block:: html+twig
{% set value = 'no spaces' %}
{#- No leading/trailing whitespace -#}
{%- if true -%}
{{- value -}}
{%- endif -%}
{# output 'no spaces' #}
<li>
{{ value }} </li>
{# outputs '<li>\n no spaces </li>' #}
<li>
{{- value }} </li>
{# outputs '<li>no spaces </li>' #}
<li>
{{~ value }} </li>
{# outputs '<li>\nno spaces </li>' #}
.. tip::
In addition to the whitespace modifiers, Twig also has a ``spaceless`` filter
that removes whitespace **between HTML tags**:
.. code-block:: html+twig
{% apply spaceless %}
<div>
<strong>foo bar</strong>
</div>
{% endapply %}
{# output will be <div><strong>foo bar</strong></div> #}
The ``apply`` tag was introduced in Twig 2.9; use the ``filter`` tag with
previous versions.
Extensions
----------
Twig can be extended. If you want to create your own extensions, read the
:ref:`Creating an Extension <creating_extensions>` chapter.
.. _`Twig bundle`: https://github.com/Anomareh/PHP-Twig.tmbundle
.. _`Jinja syntax plugin`: http://jinja.pocoo.org/docs/integration/#vim
.. _`vim-twig plugin`: https://github.com/lumiliet/vim-twig
.. _`Twig syntax plugin`: http://plugins.netbeans.org/plugin/37069/php-twig
.. _`Twig plugin`: https://github.com/pulse00/Twig-Eclipse-Plugin
.. _`Twig language definition`: https://github.com/gabrielcorpse/gedit-twig-template-language
.. _`Twig syntax mode`: https://github.com/bobthecow/Twig-HTML.mode
.. _`other Twig syntax mode`: https://github.com/muxx/Twig-HTML.mode
.. _`Notepad++ Twig Highlighter`: https://github.com/Banane9/notepadplusplus-twig
.. _`web-mode.el`: http://web-mode.org/
.. _`regular expressions`: https://secure.php.net/manual/en/pcre.pattern.php
.. _`PHP-twig for atom`: https://github.com/reesef/php-twig
.. _`TwigFiddle`: https://twigfiddle.com/
.. _`Twig pack`: https://marketplace.visualstudio.com/items?itemName=bajdzis.vscode-twig-pack
|