Insignificant whitespace postprocessor filter for Coral programming language, a part of proof-of-concept PHP implementation

InsignificantWhitespaceFilter.php

<?php
namespace Coral\Compiler\Postprocessor;

use Coral\Compiler\Tokenizer\Tokens\Token;
use Coral\Compiler\Tokenizer\Tokens\WhitespaceToken;
use Coral\Internal\Object;

class InsignificantWhitespaceFilter extends Object implements Filter
{
	public function apply_filter ($tokens)
	{
		return \array_filter($tokens, function ($token) {
			return $this->is_token_allowed($token);
		});
	}

	private function is_token_allowed (Token $token)
	{
		if (!($token instanceof WhitespaceToken))
		{
			return true;
		}
		elseif ($token->getContent() === "\n")
		{
			return true;
		}
		else
		{
			return false;
		}
	}
}