想將html的font 3個子標示size,color,face變成ubb
文本
文本
[face=$face]文本[/face]
有以下變化







想變成
(face="")(/face)
(size="" )(/size)
(color="")(/color)
(face=)(size=)(/size)(/face)
(size=)(color=)(/color)(/size)
(face=)(color=)(/color)(/face)
(face=)(size=)(color=)(/color)(/size)(/face)
正規表達如何做？