| David Combs 2004-03-29, 6:50 pm |
| In article <c2sasr$4u0$1@nets3.rz.RWTH-Aachen.DE>,
Tassilo v. Parseval <tassilo.parseval@post.rwth-aachen.de> wrote:
>Also sprach J Krugman:
>
[color=darkred]
>People will probably be using one or the other, but not both.
Not that I'm all that good with either, but I
do use both.
Emacs is "up", and I'm "in" it, nearly 100% of the time:
things like *shell* and dired make dealing with the computer
*so much easier* -- and efficient too.
Vi{,m} has one rather unique featured: its "g" (and "v") command,
which work like this:
80,900g/mypat/<some ex-command>
where <some ex-command> can be *any* ex-command -- other than
another v or g command.
like this:
g/myregexp/.-2,.+2s/^/foo/
which works like this, using TWO PASSES:
pass-1: goes through lines 80 through 900, seeing which ones
have a match for myregexp, and for those that do,
turn on a bit (attached to the LINE ITSELF, not the
line-NUMBER).
pass-2 for every line in the file (I guess, so things work
out right), for those that have that bit turned on,
*do that <some ex-command>, in this case,
.-2,.+2s/^/foo/
, where "." is interpreted as the current 2nd-pass line-number.
That is, if in the 2nd pass, we're now at line 458, and
that line does have that bit turned "on", then this
is executed:
456,460s/^/foo/
What's  is that it still works if the attached-command
changes the number of lines, eg if the command had been:
.-5r myfile.txt
, which of course changes the line-number that of the line
the 2nd-pass is now at.
But that does NOT screw-up everything, because as that line
"moves around (via its linenumber)", that bit MOVES ALONG WITH IT!
Which makes everything work.
Which is pretty darned .
And which seems to be fully documented only in the classic
Kernighan book, "Software Tools" (from way back in the mid
70's), and which is *still* very much reading (actually,
studying)
Not so easy to do in emacs, mainly because vi works via an
indexable *array* of lines, where emacs works one single
super=long array *of characters* -- which enables a whole
different kind wonderful magic too.
David
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