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Date: Mon, 7 Jan 2013 11:10:27 -0600
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Subject: new Class ReflectionZVal
From: nathan@starin.biz

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I wanted some thought from you guys about the idea of giving PHP scripts the
ability to read some internal information about variables such as ZVals.

 

The idea of how this reflection class would work would be something like:

 

Class ReflectionZVal {

    // Retains info about the variable referenced

    function __construct(&$variable);

    // Returns if the referenced variable

    function valueExists();

    // Returns a ref to the variable or throws error if value is gone.

    function &getValue();

    // Returns the reference count of the variable

    function getRefCount();

    // Returns the current type associated with the referenced variable

    function getType();

    // Returns bool of if getValueReflection() is callable. (see note below)

    function isValueReflectable();

    // Returns a new instance of ReflectionZVal for the value of variable
passed in construct. (returns null and throws error if value is not a ref of
a variable)

    function getValueReflection();

}

 

The idea of this class would give PHP the ability to read reference count
info and have read-only access to values stored in variables without causing
PHP to not be able to use the internal garbage collector. An example of how
this could be useful would be if you had a class structure that matched a
database table structure. Every time a new record of the table was returned
it constructed a new object. It is more practical to have the class store
each object that was constructed into a static variable attached to each
class structure and when a new record is requested it first checks to see if
the object with the same row has already been constructed and use/update
that object instead of making (possibly) many duplicates. This gives the
code structure the ability that if the same record was requested then later
in the execution the same row was requested again and modified it would also
modify it everywhere that object/row was already requested. The issue with
this structure is that php's garbage collector will never clean up those
constructed objects because the class needs a reference to them and cannot
know if other places in the code has references to them.

 

If a reflection like this one was available it would give the ability to
contain a reference to variables/pointers without increasing the reference
count. It would allow a class structure (like stated above) to call it's own
garbage collector every once in a while to clean up those ReflectionZVal
objects by checking the result of ReflectionZVal:: valueExists ().

 

Is there anything obvious (limitation wise) that I am missing or is this
RFC'able?

 

Software Developer

Nathan Bruer


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