#PHP ARRAY CONSTANT CODE#

getConstants() ¶įor this small problem i am using function getConstants(). A valid constant name must start with an alphabet or underscore and requires no ‘’.

It is ideal to keep all the constants in a single PHP script so that maintenance is made easier.

#PHP ARRAY CONSTANT CODE#

when class constants are declared).For time to time i have models with constants (basicly status constants) which i use in diferent places and if these constant changes, i have to change mentions of constant in code elsewhere. A PHP constant is nothing but an identifier for a simple value that tends not to change over time (such as the domain name of a website eg. If the evaluation fails the nodes stay AST nodes and will again be evaluated at runtime when more information is available (e.g. It traverses the AST and tries to compile-time evaluate all nodes by evaluating their children first and then the node itself if the child nodes were successfully evaluated. PHP Constant Arrays In PHP7, you can create an Array constant using the define () function. Here's a quick explanation of how this is implemented: During compilation of static variables the initializer AST is passed to the zend_eval_const_expr function. If $a is modified at any point between the two initializations the initial value of $b also changes. which implementors MAY replace with values from the context array. Use the php constant PHPEOL to print the correct end of line symbol no matter what system. However, that's not necessarily the case. Calling this method with one of the log level constants MUST have the same result as. In this example it's clear that $a holds the value 0 until the initialization of $b. In the discussion the question arose whether static variables depending on other static variables are known at compile time.

Static $x = $i < 3 ? foo ( $i + 1 ) : 'Done' var_dump ( $x ) return $i }įoo ( 1 ) // string(4) 'Done', $i = 3 // string(4) 'Done', $i = 2 // string(4) 'Done', $i = 1įoo ( 5 ) // string(4) 'Done', $i = 5, initializer not called What initializers are known at compile-time? However, I cannot imagineĪ useful scenario for recursive static variable initializers, so semantics here are unlikely to matter. Not reassigning the value avoids this issue. This is a somewhat technical limitation where the opcode needs to release two values that couldīoth execute user code and thus throw exceptions. Note though that the assignment to the static variable I will be working on further refining this idea, maybe even to something like an external static class, possibly using the '.' token to allow variable length arguments. A valid constant name starts with a letter or underscore, followed by any number of letters, numbers, or underscores. This means that the initializer will be called multiple times. The name of a constant follows the same rules as any label in PHP. This accepts a string of the constant name and will return a. Initializer calls the current function recursively this check will be reached before the function has been initialized. The built in PHP function defined() can be used to test for the existence of a constant value. The static variable declaration only runs the initializer if the static variable has not been initialized. Static $x = $initialValue } var_dump ( ( new ReflectionFunction ( 'foo' ) ) -> getStaticVariables ( ) ) // NULLįoo ( 1 ) var_dump ( ( new ReflectionFunction ( 'foo' ) ) -> getStaticVariables ( ) ) // 1įoo ( 2 ) var_dump ( ( new ReflectionFunction ( 'foo' ) ) -> getStaticVariables ( ) ) // 1įrom the example above, it becomes more obvious why the initializer $initialValue cannot be evaluated before After executing the function and assigning to the static variable the contents of the variable willīe reflectable through ReflectionFunction :: getStaticVariables ( ). If successful, the value will be embedded in the static variables table. If you create a construct() function, PHP will automatically call this function when you create an object from a class. Instead, the compiler will attempt to resolve the constant expression atĬompile time. On values that are only known at runtime. With this RFC this is no longer possible, as static variables may depend

Variable if the function has never been called. Currently, PHP automatically evaluates the underlying constant expression and initializes the static

ReflectionFunction :: getStaticVariables ( ) can be used to inspect a function's static variables and theirĬurrent values.

Php array constant