Scope

Scope offers a mechanism for preparing global environments and containers for the duration of a callback, keeping state mutation and clean-up to only declaration in your code. Inspired by Python's native with., _(*1)

For example, instead of doing:, _(*2)

global $x;
$xBackup = $x;
$x = $xNew;
$done = do_it();
$x = $xBackup;

with KeyState you can set an Array key state:, _(*3)

(new KeyState($GLOBALS, array("x" => $newX)))->call('do_it');

Currently available scopes help with:, _(*4)

Collecting multiple scopes together, with Scope;
Setting temporary values on arrays, with KeyState;
Capturing function output, with Buffer;
Changing into a new directory, with WorkingDirectory; and
Worrying about different error levels, with ErrorReporting.

Sometimes you'll want to hop in and out of a given scope, providing default context by following the changes incurred by your actions within. The scopes can optionally account for this. The Buffer can collect the output across multiple sessions; the WorkingDirectory can go back to the directory it left upon re-entry; the KetState can track the value of keys, should they be changed in-scope; and the ErrorReporting can track any changes to the reporting. See the spec tests for details., _(*5)

All entered scopes are passed into the callback as function arguments. For example, when working with output buffers you can capture and return the output as so:, _(*6)

$output = (new Scope(
    new Buffer(Buffer::CLEAN),
    new WorkingDirectory("./old")
))->call(function(Buffer $buffer) {
    require "old-script.php";
    return $buffer->getContents();
});

If exceptions are thrown during the callback then we close the scopes and re-throw the exception. If exceptions are thrown by the scopes then we clean up any already entered and re-throw the exception. Exceptions thrown whilst trying to leave a scope prevent the clean-up of others (which should perhaps change)., _(*7)