case-replace

[John Yates]

Here is a description of case-replace as it behaves today:

| Replacement transfers the case
| pattern of the old text to the new text, if `case-replace' and
| `case-fold-search' are non-nil and FROM-STRING has no uppercase
| letters.  (Transferring the case pattern means that if the old text
| matched is all caps, or capitalized, then its replacement is upcased
| or capitalized.)

Thus we give a request to replace 'ab' by 'xyz' we get

ab -> xyz
Ab -> Xyz
AB -> XYZ
aB -> xyz    <<<<

These rules make sense when FROM and TO differ in length.

I often find myself replacing a FROM string with a TO of identical
length.  In such a case I would really appreciate it if case were
preserved at each character position.  E.g. replacing 'ab' by 'xy'
would give me:

ab -> xy
Ab -> Xy
AB -> XY
aB -> xY    <<<<

/john