[boost] [regex] access to subexpressions

From: Lorenzo Bettini (bettini_at_[hidden])
Date: 2007-05-05 13:06:35

Hi

is there a way to access the subexpressions in a tree-like manner?

For instance, suppose I have this regular expression

((").*(\2))

that matches against this string

test"ooo"foo

the results are

prefix: test
what[0]: "ooo"
  what[1]: "ooo"
  length: 5
  what[2]: "
  length: 1
  what[3]: "
  length: 1
suffix: foo

I need to format the matched part with tags, say, like this

<matched>
 <sub>"</sub>
 ooo
 <sub>"</sub>
</matched>

but in order to do this, when I inspect what[1], I'd need to know that
it has two subexpressions, while I cannot know that what[2] and what[3]
are indeed subexpressions of what[1]...

That is to say, subexpressions are flattened.

thanks in advance
       Lorenzo

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