It should be possible to use regular expressions (at least references to search groups, i.e. $n) for replacing in Search and Replace.

Among the uses of such functionality would be finding (and automatically populating/changing) segments where source and target should be identical, or segments where only a part of original is used in translation, like numbers with units etc., or working with similar languages where the stem of a certain word should remain intact, but inflexions should be changed.

Ideally, the Replace should be capable not only of using RegEx, but of things like .toUpperCase() or arithmetics.