Alternations

Alternations

Alternations create alternative for the current container.

REBuilder provides two classes to manage alternations: REBuilder\Pattern\AlternationGroup and REBuilder\Pattern\Alternation. These classes allow to group all the alternations in a common container (AlternationGroup) that accepts only alternations as children:

To create alternations you must first create an alternation group using addAlternationGroup and then you can add multiple alternations to it using addAlternation:

$regex
      ->addAlternationGroup()    //Create the alternation group
            ->addAlternation()   //Add the first alternation
                  ->addChar("a") //Match the "a" character
                  ->getParent()  //Back to assertion
            ->getParent()        //Back to assertion group
            ->addAlternation()   //Add the second alternation
                  ->addChar("b"); //Match the "b" character;
echo $regex; // "/(?:a|b)/"

Note that AlternationGroup can contain only Alternation class instances so if you use addChild and pass a different pattern it will throw an exception. Note also that Alternation can be added only to AlternationGroup, adding it to another container or using add addAlternation on containers different from AlternationGroup will throw an exception.