Re: History for query replace pairs

[Artur Malabarba]

>>> - You still have access to the "TO-history" in the FROM case, indirectly
>>> (by browsing the corresponding FROM/TO pair and erasing the FROM and
>>> the separator).
>> The only problematic part is that if the user will be able
>> to erase the separator, then the user rightfully might want
>> to insert it back, but it's not straightforward to type a string
>> with text properties.
>
> `undo' should do it.
>

If this line is followed, I'd recommend rebinding one of the transpose
commands (transpose-lines, perhaps) to swap the TO and FROM. Having to
manually kill and yank would be a very cumbersome way of reversing the
replacement.