regexp repacement, how to present replacement to user?

[Paul Pogonyshev <pogonyshev@gmx.net>]

Hi,

I basically have a loop of `re-search-forward' with optional `replace-match'
after that.  I'd like to ask user if the particular match should be replaced
or not.  However, I'd like to present user with end-result strings, i.e. not
regexp and replacement with \N strings, but the match string and what
replacement would be in this case.  The former is as easy as (match-string 0),
but the second is not obvious how to do.

I.e., to clarify, I'd like this:

	Replace "foo-bar" with "foo bar"?

instead of this:

	Replace "\([[:alpha:]]+\)-\([[:alpha:]]+\)" with "\1 \2"?

Paul