storeengine / includes / classes / eval-math / eval-math-stack.php

eval-math-stack.php in StoreEngine — Complete eCommerce Solution with Memberships, Licensing, Affiliates & More 2.2.0, at includes/classes/eval-math/eval-math-stack.php

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1	<?php
2
3	namespace StoreEngine\Classes\EvalMath;
4
5	if ( ! defined( 'ABSPATH' ) ) {
6	exit;
7	}
8
9	/**
10	* Class EvalMathStack
11	*
12	* Expression-evaluator stack.
13	*/
14	class EvalMathStack {
15
16	/**
17	* Stack array.
18	*
19	* @var array
20	*/
21	public $stack = array();
22
23	/**
24	* Stack counter.
25	*
26	* @var integer
27	*/
28	public $count = 0;
29
30	/**
31	* Push value into stack.
32	*
33	* @param mixed $val
34	*/
35	public function push( $val ) {
36	$this->stack[ $this->count ] = $val;
37	$this->count++;
38	}
39
40	/**
41	* Pop value from stack.
42	*
43	* @return mixed
44	*/
45	public function pop() {
46	if ( $this->count > 0 ) {
47	$this->count--;
48	return $this->stack[ $this->count ];
49	}
50	return null;
51	}
52
53	/**
54	* Get last value from stack.
55	*
56	* @param int $n
57	*
58	* @return mixed
59	*/
60	public function last( $n = 1 ) {
61	$key = $this->count - $n;
62	return array_key_exists( $key, $this->stack ) ? $this->stack[ $key ] : null;
63	}
64	}
65