--- ray/doc/man/man1/rcalc.1	2006/12/23 17:27:45	1.7
+++ ray/doc/man/man1/rcalc.1	2012/02/03 17:55:16	1.9
@@ -1,4 +1,4 @@
-.\" RCSid "$Id: rcalc.1,v 1.7 2006/12/23 17:27:45 greg Exp $"
+.\" RCSid "$Id: rcalc.1,v 1.9 2012/02/03 17:55:16 greg Exp $"
 .TH RCALC 1 4/6/99 RADIANCE
 .SH NAME
 rcalc - record calculator
@@ -202,7 +202,8 @@ and the following operators:
 .PP
 	+  -  *  /  ^
 .PP
-Operators are evaluated left to right.
+Operators are evaluated left to right, except '^',
+which is right associative.
 Powers have the highest precedence; multiplication and
 division are evaluated before addition and subtraction.
 Expressions can be grouped with parentheses.
@@ -234,6 +235,11 @@ are evaluated.
 This provides a convenient method for avoiding inappropriate calculations.
 The following library of pre-defined functions and variables is provided:
 .TP 10n
+.BR \$N
+Return the value for input column
+.I N.
+If an input format is given, using a channel number generates an error.
+.TP
 .BR "in(n)"
 Return the value for input column
 .I n,
@@ -293,12 +299,12 @@ trigonometric functions.
 inverse trigonometric functions.
 .TP
 .BR "atan2(y, x)"
-inverse tangent of y/x (range -pi to pi).
+inverse tangent of y/x (range \-pi to pi).
 .SH EXAMPLE
 To print the square root of column two in column one,
 and column one times column three in column two:
 .IP "" .2i
-rcalc -e '$1=sqrt($2);$2=$1*$3' inputfile > outputfile
+rcalc \-e '$1=sqrt($2);$2=$1*$3' inputfile > outputfile
 .SH AUTHOR
 Greg Ward
 .SH BUGS