bug#25355: 26.0.50; Provide function to non-destructively replace buffer contents

[Philipp Stephani]

Philipp <p.stephani2@gmail.com> schrieb am Mi., 4. Jan. 2017 um 13:46 Uhr:

There are many tools (e.g. auto-formatters) that take buffer contents,
reformat them, and write the reformatted output somewhere.  However,
there is no good way how to apply the modified output to the source
buffer.  The naive way (erasing and re-inserting the buffer contents)
loses point and markers.  Therefore there should be a function
(e.g. `replace-buffer-contents') that calculates a minimal diff between
the old and the new contents and uses editing operations (insert,
delete, etc.) to apply the diff.  Ideally this would be done without any
external tools (e.g. 'diff').

FYI, I've now implemented this based on libmba (http://www.ioplex.com/~miallen/libmba/). Unless there are concerns importing part of that library into the Emacs source tree, I'll send a patch.