.LP
A "function" that was previously saved in ASCII format in a file, may be
used as input for Xprism3.  Numerous operators and functions are
supported using this method of input. Either C-style /*  */ comments
or a '#' may be used to designate comments in the functions file. If
a '#' is used, then all characters to the end of that line are ignored.
.LP
To plot a "function" file, fill in the "Filename" parameter box with the
desired filename (for more information, see the help on the Environment Pane),
and click on the "PLOT FILE" action button.  The information from the 
"function" file will be read in, interpreted as described above, and 
displayed according to the current value of the "plot type" toggle.
.LP
The syntax for specifing a function in a file is as follows:
.nf

	f(x,y) = sin(x) * cos(y) + x^2
	x = (-pi, 3.14, 40)
	y = (-pi, 3.14, 40)

.fi
The "f(x,y)=" preceding the function is a must.  The range must be in the 
form illustrated. 
If this form is not followed exactly, the parser will generate an error message.
The fields for the x and y range are as follows:
.nf

	x = (minimum point, maximum point, number of points)
	y = (minimum point, maximum point, number of points)

.fi
.LP
For more information on the Khoros expression parser, see below.
