isProtected()) return false;
        $input = $this->fromString($input);
        $value = is_null($this->local) ? $this->default : $this->local;
        if ($value == $input) return false;
        foreach ($input as $item) {
            if ($this->pattern && !preg_match($this->pattern, $item)) {
                $this->error = true;
                $this->input = $input;
                return false;
            }
        }
        $this->local = $input;
        return true;
    }
    /** @inheritdoc */
    public function html(\admin_plugin_config $plugin, $echo = false)
    {
        $disable = '';
        if ($this->isProtected()) {
            $value = $this->protected;
            $disable = 'disabled="disabled"';
        } elseif ($echo && $this->error) {
            $value = $this->input;
        } else {
            $value = is_null($this->local) ? $this->default : $this->local;
        }
        $key = htmlspecialchars($this->key);
        $value = htmlspecialchars($this->fromArray($value));
        $label = '';
        $input = '';
        return [$label, $input];
    }
}