[Boost-users] [Regex] Is it possible to assign an alias to a subexpression (to use later instead of its index)?

Hi, I would like to know if it's possible to assign an alias/name to a sub-expression. When using short regex there is no problem nor confusion but when using a long regex then I get lost looking at the correct index to use. It would be much easier if I can assign an alias. So, instead to use a regex like this: "\s*(\d+)\s+(\d+)\s+(\d+)\s+" I would like to be able to use something like: "\s*([$VALUE1]\d+)\s+([$VALUE2]\d+)\s+([$VALUE3]\d+)\s+" I don't know if this feature exists in regex but I haven't found it but maybe I dind't know where to find... Thanks in advance, Jordi