在PHP链中使用Variable作为方法来允许条件方法链

Question

Is there a way to build the chain conditionally? Example:

$chain = $restaurant->allFoods()->$filter->get();

Then $filter is dynamic or conditionally set

if ($user == "vegetarian")
{
    $filter = "->onlyVegetables()";
}

So if condition is met, the chain would become:

$chain = $restaurant->allFoods()->onlyVegetables()->get();

else

$chain = $restaurant->allFoods()->get();

Is this possible? What is this called? Thank you

Answer 1

Yes, through overloading with methods __get/__call, depending on if you need to pass arguments to the filter or not.

<?php
function __get($user) {
  if($user == 'vegetarian') {
    return $this->onlyVegetables();
  }
  return $this;
}

http://php.net/manual/en/language.oop5.overloading.php