Re: map-file-lines

[Richard M Stallman]

Here's an idea for a UI for editing big files.  First you run M-x grep on
the file, and display the matches for whatever regexp.  In the *grep*
buffer you specify a region, which is a way of choosing two matches,
the ones whose entries contain point and mark.  Then you give a command to edit
the file from one of the matches to the other.  It marks these matches
(and the lines containing them) as read-only so that you can't
spoil the correspondance with the file.  Thus, you can always save this
partial-file buffer.

The beginning and end of the *grep* buffer can be used to specify
that the portion to edit starts or ends at bof or eof.

It would be easy to adapt this to variants such as
(1) using hexl-mode to visit the file,
(2) using methods other than grep to subdivide the file,
(3) providing more friendly front ends to grep.