8000 [WIP] Add docs for ExpressionLanguage component by wouterj · Pull Request #3044 · symfony/symfony-docs · GitHub
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Merged
merged 5 commits into from
Nov 16, 2013
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[WIP] Add docs for ExpressionLanguage component #3044

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cab5c89
Creates Expression Language chapter
wouterj Oct 6, 2013
27822ff
Bootstraps intro
wouterj Oct 6, 2013
6631f70
Added operators
wouterj Oct 6, 2013
4ff9fae
Added another operator
wouterj Oct 6, 2013
8fe9fd6
Fixed comments and splitted in intro and syntax
wouterj Oct 26, 2013
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Fixed comments and splitted in intro and syntax
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@wouterj
wouterj committed Oct 26, 2013
commit 8fe9fd606fdf4b0b20bf55606b9b7472b3965c83
1 change: 1 addition & 0 deletions components/expression_language/index.rst
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Expand Up @@ -5,3 +5,4 @@ Expression Language
:maxdepth: 2

introduction
syntax
100 changes: 7 additions & 93 deletions components/expression_language/introduction.rst
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Expand Up @@ -10,14 +10,14 @@ The ExpressionLanguage Component
(mostly, but not limited to, Booleans).

.. versionadded:: 2.4
The ExpressionLanguage Component was new in Symfony 2.4.
The ExpressionLanguage component was new in Symfony 2.4.
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was introduced in


Installation
------------

You can install the component in 2 different ways:

* Use the official Git repository (https://github.com/symfony/ExpressionLanguage);
* Use the official Git repository (https://github.com/symfony/expression-language);
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preach it and practice 👶

* :doc:`Install it via Composer </components/using_components>` (``symfony/expression-language`` on `Packagist`_).
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I think we should document Composer first as it is the recommended way

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I like it, but this means we should change it in all component docs. I'll open a ticket for it.

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#3102

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We changed the order of these recently


Usage
Expand All @@ -29,7 +29,7 @@ compare them to the expression in an ``if`` statement. A simple example of an
expression is ``1 + 2``. You can also use more complicated expressions, such
as ``someArray[3].someMethod('bar')``.

The component provide 2 ways to work with expressions:
The component provides 2 ways to work with expressions:

* **compile**: the expression is compiled to PHP, so it can be cached and
evaluated;
Expand All @@ -46,96 +46,10 @@ The main class of the component is

echo $language->compile('1 + 2'); // displays (1 + 2)

Supported Literals
~~~~~~~~~~~~~~~~~~
Expression Syntax
-----------------

The component supports:

* **strings** - single and double quotes (e.g. ``'hello'``)
* **numbers** - e.g. ``103``
* **arrays** - using twig notation (e.g. ``[1, 2]``)
* **hashes** - using twig notation (e.g. ``{ foo: 'bar' }``)
* **booleans** - ``true`` and ``false``
* **null** - ``null``

Supported Operators
~~~~~~~~~~~~~~~~~~~

The component comes with a lot of operators:

Arithmetic Operators
....................

* ``+`` (addition)
* ``-`` (subtraction)
* ``*`` (multiplication)
* ``/`` (division)
* ``%`` (modulus)
* ``**`` (pow)

Assignment Operators
....................

* ``=``

Bitwise Operators
.................

* ``&`` (and)
* ``|`` (or)
* ``^`` (xor)

Comparison Operators
....................

* ``==`` (e EDBE qual)
* ``===`` (identical)
* ``!=`` (not equal)
* ``!==`` (not identical)
* ``<`` (less than)
* ``>`` (greater than)
* ``<=`` (less than or equal to)
* ``>=`` (greater than or equal to)
* ``=~`` (regex match)
* ``!~`` (regex does not match)

.. sidebar:: Regex Operator

The Regex Operators (``=~`` and ``!~``) are coming from Perl. This
operator matches if the regular expression on the right side of the
operator matches the string on the left. For instance,
``'foobar' =~ '/foo/'`` evaluates to true.
``!~`` is the opposite and matches if the regular expression does *not*
match the string.

Logical Operators
.................

* ``not`` or ``!``
* ``and`` or ``&&``
* ``or`` or ``||``

String Operators
................

* ``~`` (concatenation)

Array Operators
...............

* ``in`` (contain)
* ``not in`` (does not contain)

Numeric Operators
.................

* ``..`` (range)

Ternary Operators
.................

* ``foo ? 'yes' : 'no'``
* ``foo ?: 'no'`` (equal to ``foo ? foo : 'no'``)
* ``foo ? 'yes'`` (equal to ``foo ? 'yes' : ''``)
See ":doc:`/components/expression_language/syntax`" to learn the syntax of the
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syntax used with

ExpressionLanguage component.

.. _Packagist: https://packagist.org/packages/symfony/expression-language
98 changes: 98 additions & 0 deletions components/expression_language/syntax.rst
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@@ -0,0 +1,98 @@
.. index::
single: Syntax; ExpressionLanguage

The Expression Syntax
=====================

The ExpressionLanguage component uses a specific syntax which is based on the
expression syntax of Twig. In this document, you can find all supported
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extra comma can be removed

syntaxes.

Supported Literals
~~~~~~~~~~~~~~~~~~

The component supports:

* **strings** - single and double quotes (e.g. ``'hello'``)
* **numbers** - e.g. ``103``
* **arrays** - using twig notation (e.g. ``[1, 2]``)
* **hashes** - using twig notation (e.g. ``{ foo: 'bar' }``)
* **booleans** - ``true`` and ``false``
* **null** - ``null``

Supported Operators
~~~~~~~~~~~~~~~~~~~

The component comes with a lot of operators:

Arithmetic Operators
....................

* ``+`` (addition)
* ``-`` (subtraction)
* ``*`` (multiplication)
* ``/`` (division)
* ``%`` (modulus)
* ``**`` (pow)

Assignment Operators
....................

* ``=``

Bitwise Operators
.................

* ``&`` (and)
* ``|`` (or)
* ``^`` (xor)

Comparison Operators
....................

* ``==`` (equal)
* ``===`` (identical)
* ``!=`` (not equal)
* ``!==`` (not identical)
* ``<`` (less than)
* ``>`` (greater than)
* ``<=`` (less than or equal to)
* ``>=`` (greater than or equal to)
* ``matches`` (regex match)

.. tip::

To test if a string does *not* match a regex, use the logical ``not``
operator in combination with the ``matches`` operator::

$language->evaluate('not "foo" matches "/bar/"'); // returns true
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are we allowed to place also () to group expressions? just curious


Logical Operators
.................

* ``not`` or ``!``
* ``and`` or ``&&``
* ``or`` or ``||``

String Operators
................

* ``~`` (concatenation)

Array Operators
...............

* ``in`` (contain)
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contains

* ``not in`` (does not contain)

Numeric Operators
.................

* ``..`` (range)

Ternary Operators
.................

* ``foo ? 'yes' : 'no'``
* ``foo ?: 'no'`` (equal to ``foo ? foo : 'no'``)
* ``foo ? 'yes'`` (equal to ``foo ? 'yes' : ''``)
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is this also true in twig, interesting, never knew elvis operator had another version

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as of Twig 1.12, it is supported

However, in the ExpressionLanguage component, the implicit else value is null, not the empty string

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shouldn't it be null on evaluation and '' on compilation maybe? just saying

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nope. The compilation and the evaluation are producing the same result (after evaluating the compiled code).
And these shortcuts are handled by the parser, not by the evaluator or the compiler.

Using an empty string i the doc is because it was written before changing it to null (the initial code was copied from Twig which uses an empty string)

1 change: 1 addition & 0 deletions components/map.rst.inc
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Expand Up @@ -60,6 +60,7 @@
* :doc:`/components/expression_language/index`

* :doc:`/components/expression_language/introduction`
* :doc:`/components/expression_language/syntax`

* **Filesystem**

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