You could write your own custom macros on php in "client/custom_macros/index.php". Every method of CustomMacros class is custom macros.

Then you need register you macros in "client/custom_macros/PugAdapter.php" file.

You need extend array in function getCustomMacros() {
$macros = $this->macros;
return [
$this->prefix.'yourCustomMacrosName' => function(params /* if it need */) use($macros){
return $macros->yourCustomMacrosName(params /* if it need */);
}
];
}

Now you can call your macro in a pug template - customMacro_yourCustomMacrosName(params)