Gregwar\RST\Environment::getLevel PHP Method

    public function getLevel($letter)
    {
        foreach ($this->titleLetters as $level => $titleLetter) {
            if ($letter == $titleLetter) {
                return $level;
            }
        }
        $this->currentTitleLevel++;
        $this->titleLetters[$this->currentTitleLevel] = $letter;
        return $this->currentTitleLevel;
    }