发布于 2015-08-27 16:47:32 | 198 次阅读 | 评论: 0 | 来源: 网络整理
The ExpressionLanguage component uses a specific syntax which is based on the expression syntax of Twig. In this document, you can find all supported syntaxes.
The component supports:
'hello')103[1, 2]){ foo: 'bar' })true and falsenullWhen passing objects into an expression, you can use different syntaxes to access properties and call methods on the object.
Public properties on objects can be accessed by using the . syntax, similar
to JavaScript:
class Apple
{
public $variety;
}
$apple = new Apple();
$apple->variety = 'Honeycrisp';
echo $language->evaluate(
'fruit.variety',
array(
'fruit' => $apple,
)
);
This will print out Honeycrisp.
The . syntax can also be used to call methods on an object, similar to
JavaScript:
class Robot
{
public function sayHi($times)
{
$greetings = array();
for ($i = 0; $i < $times; $i++) {
$greetings[] = 'Hi';
}
return implode(' ', $greetings).'!';
}
}
$robot = new Robot();
echo $language->evaluate(
'robot.sayHi(3)',
array(
'robot' => $robot,
)
);
This will print out Hi Hi Hi!.
You can also use registered functions in the expression by using the same
syntax as PHP and JavaScript. The ExpressionLanguage component comes with one
function by default: constant(), which will return the value of the PHP
constant:
define('DB_USER', 'root');
echo $language->evaluate(
'constant("DB_USER")'
);
This will print out root.
小技巧
To read how to register your own functions to use in an expression, see “Extending the ExpressionLanguage”.
If you pass an array into an expression, use the [] syntax to access
array keys, similar to JavaScript:
$data = array('life' => 10, 'universe' => 10, 'everything' => 22);
echo $language->evaluate(
'data["life"] + data["universe"] + data["everything"]',
array(
'data' => $data,
)
);
This will print out 42.
The component comes with a lot of operators:
+ (addition)- (subtraction)* (multiplication)/ (division)% (modulus)** (pow)For example:
echo $language->evaluate(
'life + universe + everything',
array(
'life' => 10,
'universe' => 10,
'everything' => 22,
)
);
This will print out 42.
& (and)| (or)^ (xor)== (equal)=== (identical)!= (not equal)!== (not identical)< (less than)> (greater than)<= (less than or equal to)>= (greater than or equal to)matches (regex match)小技巧
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
You must use parenthesis because the unary operator not has precedence
over the binary operator matches.
Examples:
$ret1 = $language->evaluate(
'life == everything',
array(
'life' => 10,
'universe' => 10,
'everything' => 22,
)
);
$ret2 = $language->evaluate(
'life > everything',
array(
'life' => 10,
'universe' => 10,
'everything' => 22,
)
);
Both variables would be set to false.
not or !and or &&or or ||For example:
$ret = $language->evaluate(
'life < universe or life < everything',
array(
'life' => 10,
'universe' => 10,
'everything' => 22,
)
);
This $ret variable will be set to true.
~ (concatenation)For example:
echo $language->evaluate(
'firstName~" "~lastName',
array(
'firstName' => 'Arthur',
'lastName' => 'Dent',
)
);
This would print out Arthur Dent.
in (contain)not in (does not contain)For example:
class User
{
public $group;
}
$user = new User();
$user->group = 'human_resources';
$inGroup = $language->evaluate(
'user.group in ["human_resources", "marketing"]',
array(
'user' => $user,
)
);
The $inGroup would evaluate to true.
.. (range)For example:
class User
{
public $age;
}
$user = new User();
$user->age = 34;
$language->evaluate(
'user.age in 18..45',
array(
'user' => $user,
)
);
This will evaluate to true, because user.age is in the range from
18 to 45.
foo ? 'yes' : 'no'foo ?: 'no' (equal to foo ? foo : 'no')foo ? 'yes' (equal to foo ? 'yes' : '')