class Variable

class Variable {
    
    /**
     * Generates a human-readable name for a callable.
     *
     * @param callable $callable
     *   A callable.
     *
     * @return string
     *   A human-readable name for the callable.
     */
    public static function callableToString($callable) : string {
        if ($callable instanceof \Closure) {
            return '[closure]';
        }
        elseif (is_array($callable) && $callable) {
            if (is_object($callable[0])) {
                $callable[0] = get_class($callable[0]);
            }
            return implode('::', $callable);
        }
        elseif (is_string($callable)) {
            return $callable;
        }
        else {
            return '[unknown]';
        }
    }
    
    /**
     * Drupal-friendly var_export().
     *
     * @param mixed $var
     *   The variable to export.
     * @param string $prefix
     *   A prefix that will be added at the beginning of every lines of the output.
     *
     * @return string
     *   The variable exported in a way compatible to Drupal's coding standards.
     */
    public static function export($var, $prefix = '') {
        if (is_array($var)) {
            if (empty($var)) {
                $output = 'array()';
            }
            else {
                $output = "array(\n";
                // Don't export keys if the array is non associative.
                $export_keys = array_values($var) != $var;
                foreach ($var as $key => $value) {
                    $output .= '  ' . ($export_keys ? static::export($key) . ' => ' : '') . static::export($value, '  ', FALSE) . ",\n";
                }
                $output .= ')';
            }
        }
        elseif (is_bool($var)) {
            $output = $var ? 'TRUE' : 'FALSE';
        }
        elseif (is_string($var)) {
            if (strpos($var, "\n") !== FALSE || strpos($var, "'") !== FALSE) {
                // If the string contains a line break or a single quote, use the
                // double quote export mode. Encode backslash, dollar symbols, and
                // double quotes and transform some common control characters.
                $var = str_replace([
                    '\\',
                    '$',
                    '"',
                    "\n",
                    "\r",
                    "\t",
                ], [
                    '\\\\',
                    '\\$',
                    '\\"',
                    '\\n',
                    '\\r',
                    '\\t',
                ], $var);
                $output = '"' . $var . '"';
            }
            else {
                $output = "'" . $var . "'";
            }
        }
        elseif (is_object($var) && get_class($var) === 'stdClass') {
            // var_export() will export stdClass objects using an undefined
            // magic method __set_state() leaving the export broken. This
            // workaround avoids this by casting the object as an array for
            // export and casting it back to an object when evaluated.
            $output = '(object) ' . static::export((array) $var, $prefix);
        }
        else {
            $output = var_export($var, TRUE);
        }
        if ($prefix) {
            $output = str_replace("\n", "\n{$prefix}", $output);
        }
        return $output;
    }

}