Returns the property path to the value that the validator is currently validating.
For example, take the following object graph:
<pre> (Person)---($address: Address)---($street: string) </pre>
When the <tt>Person</tt> instance is passed to the validator, the property path is initially empty. When the <tt>$address</tt> property of that person is validated, the property path is "address". When the <tt>$street</tt> property of the related <tt>Address</tt> instance is validated, the property path is "address.street".
Properties of objects are prefixed with a dot in the property path. Indices of arrays or objects implementing the {@link \ArrayAccess} interface are enclosed in brackets. For example, if the property in the previous example is <tt>$addresses</tt> and contains an array of <tt>Address</tt> instance, the property path generated for the <tt>$street</tt> property of one of these addresses is for example "addresses[0].street".
string $subPath Optional. The suffix appended to the current: property path.
string The current property path. The result may be an empty string if the validator is currently validating the root value of the validation graph.
public function getPropertyPath($subPath = '');