YetiForceCompany/YetiForceCRM

<?php
/* +**********************************************************************************
 * The contents of this file are subject to the vtiger CRM Public License Version 1.0
 * ("License"); You may not use this file except in compliance with the License
 * The Original Code is:  vtiger CRM Open Source
 * The Initial Developer of the Original Code is vtiger.
 * Portions created by vtiger are Copyright (C) vtiger.
 * All Rights Reserved.
 * ********************************************************************************** */

/**
 * This is a simple parser for conditional expressions used to trigger workflow actions.
 */
class VTConditionalParser
{
    public function __construct($expr)
    {
        $this->tokens = $this->getTokens($expr);
        $this->pos = 0;
    }

    private function getTokens($expression)
    {
        preg_match_all('/and|or|\\d+|=|\\w+|\\(|\\)/', $expression, $matches, PREG_SET_ORDER);
        $tokens = [];
        foreach ($matches as $arr) {
            $tokenVal = $arr[0];
            if (\in_array($tokenVal, ['and', 'or', '=', '(', ')'])) {
                $tokenType = 'op';
            } elseif (is_numeric($tokenVal)) {
                $tokenType = 'num';
            } else {
                $tokenType = 'sym';
            }
            $tokens[] = [$tokenType, $tokenVal];
        }
        return $tokens;
    }

    public function parse()
    {
        $op = [
            'and' => ['op', 'and'],
            'or' => ['op', 'or'],
            '=' => ['op', '='],
            '(' => ['op', '('],
            ')' => ['op', ')'], ];

        if ($this->peek() == $op['(']) {
            $this->nextToken();
            $left = $this->parse();
            if ($this->nextToken() != $op[')']) {
                throw new VTParseFailed();
            }
        } else {
            $left = $this->cond();
        }
        if (\count($this->tokens) > $this->pos && \in_array($this->peek(), [$op['and'], $op['or']])) {
            $nt = $this->nextToken();

            return [$nt[1], $left, $this->parse()];
        }
        return $left;
    }

    private function cond()
    {
        $left = $this->nextToken();
        $operator = $this->nextToken();
        $right = $this->nextToken();

        return [$operator[1], $left, $right];
    }

    private function peek()
    {
        return $this->tokens[$this->pos];
    }

    private function nextToken()
    {
        ++$this->pos;

        return $this->tokens[$this->pos - 1];
    }
}