* src/preproc/pic/lex.cpp (for_input): Add member `from'.

Update constructor.
(do_for, for_input::get, for_input::peek): Handle negative `by'.
* src/preproc/pic/pic.man, doc/pic.ms, NEWS: Document it.

1 files changed, 11 insertions, 1 deletions

diff --git a/doc/pic.ms b/doc/pic.ms
index c900e75d..78080cba 100644
--- a/doc/pic.ms
+++ b/doc/pic.ms
@@ -10,7 +10,7 @@
 .\" This document was written for free use and redistribution by
 .\" Eric S. Raymond <esr@thyrsus.com> in August 1995.
 .\"
-.\"	$Id: pic.ms,v 1.26 2004/05/28 21:43:36 wlemb Exp $	
+.\"	$Id: pic.ms,v 1.27 2004/07/19 20:04:22 wlemb Exp $	
 .\"
 .\" Set a proper TeX and LaTeX
 .ie t \{\
@@ -1886,6 +1886,16 @@ then
 .I variable
 will instead be multiplied by
 \fIexpr3\fR.
+The value of
+.I expr3
+can be negative for the additive case;
+.I variable
+is then tested whether it is greater than or equal to
+\fIexpr2\fR.
+For the multiplicative case,
+.I expr3
+must be greater than zero.
+If the constraints aren't met, the loop isn't executed.
 .I X
 can be any character not occurring in
 \fIbody\fR; or the two \fIX\/\fPs may be paired braces (as in the