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Hooks¶

There's one hook available in the parser library. It allows the manipulation of the value resulting from an expression. It must be registered with something like:

$GLOBALS['TYPO3_CONF_VARS']['EXTCONF']['expressions']['postprocessReturnValue'][] = 'Vendor\\MyExtension\\Hook\\MyExpressionHook';

It must implement the \Cobweb\Expressions\ValuePostProcessorInterface interface. Here's a sample code:

namespace Vendor\MyExtension\Hook;
class MyExpressionHook implements \Cobweb\Expressions\ValuePostProcessorInterface {
        public function postprocessReturnValue($value) {
                if (is_numeric($value)) {
                        $value += 30;
                }
                return $value;
        }
}

This sample code will add 30 to the given value, if it is numeric.

As can be seen, the hook method receives the value itself and is expected to return it, even if unchanged.