Description:
------------
The extract function skips setting variables that have names that are valid but cannot be written as a simple variable.

For example, anything with dots can be written and accessed as a variable like:

${'some.config.setting'} = 'foo';
var_dump(${'some.config.setting'});

But extract considers anything with a dot in to be an invalid variable name, and so skips doing:

extract(['some.config.setting'} => 'foo']);

fails to extract it.


Test script:
---------------
$values = [
    'value.with.dot' => 'set from array',
];

extract($values);

if (!isset(${'value.with.dot'})) {
    echo "It's not set\n";
}
else {
    var_dump(${'value.with.dot'});
}

${'value.with.dot'} = "It is a valid variable name, just not one that can be written as a non-interpolated variable.";
var_dump(${'value.with.dot'});


Expected result:
----------------
string(14) "set from array"

Actual result:
--------------
It's not set