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From: amos@instable.UUCP (Amos Shapir)
Newsgroups: comp.unix.wizards
Subject: Re: help w/ a vi map
Message-ID: <820@instable.UUCP>
Date: Wed, 17-Jun-87 11:41:02 EDT
Article-I.D.: instable.820
Posted: Wed Jun 17 11:41:02 1987
Date-Received: Sun, 21-Jun-87 10:19:01 EDT
References: <7881@brl-adm.ARPA>
Reply-To: amos%nsta@nsc.com (Amos Shapir)
Distribution: world
Organization: National Semiconductor (Israel) Ltd. Home of the 32532
Lines: 25
Summary: Use double escapes in macros
Hdate: 20 Sivan 5747


In article <7881@brl-adm.ARPA> groff%community-chest.mitre.org@gateway.mitre.ORG writes:
>     I have encountered a puzzling problem w/ setting up a map in vi.
>It began w/ a file I had redirected from 'man printcap'.  This file had
>_^H's thru-out.  I could have simply done :1,$s/_^H//g and gone merrily
>on my way.  (This worked fine.)  I decided to create a map for this function
>by doing :map ^R :1,$s/_^H//g^M   - this worked SORT OF, but NOT as I would have
>expected.  (Control characters and carriage return are escaped w/ ^V.)

What happens is that you used ^V to escape the ^H when you *created* the
macro; when you *executed* it, vi got an un-escaped ^H which erased the _
resulting in the command :1,$s///g which uses the latest r.e. used,
which just happened to be the same since you tried the same command before
manually.

The correct way is to insure a ^V gets into the macro by doing
:map ^R :1,$s/_^V^V^V^H//g^V^M
which puts into the macro :1,$s/_^V^H//g^M  which does what you mean.

This triple-esacpe in macro definition is well known to anyone who ever
tried to program [nt]roff.
-- 
	Amos Shapir
National Semiconductor (Israel)
6 Maskit st. P.O.B. 3007, Herzlia 46104, Israel  Tel. (972)52-522261
amos%nsta@nsc.com @{hplabs,pyramid,sun,decwrl} 34 48 E / 32 10 N