[pstricks] Unable to successfully include PostScript code in PSTricks code

[R (Chandra) Chandrasekhar]

Dear Folks,

I am making diagrams for teaching geometric vectors using PSTricks and 
LaTeX.  I use a Debian teTeX distribution on an i386 machine and can 
provide further details of my setup if necessary.

I went through the excellent PSTricks tutorial at

http://sarovar.org/projects/pstricks/

and realized that I could use PostScript code within PSTricks commands 
to compute dimensions of geometric objects.  I value this as it would 
save me calculating separately, say, the square root of 6, and entering it.

I attach herewith a file, <Circle.tex> and a bash shell script, 
<makegraphics> which works on <Circle.tex> to successfully produce .eps 
and .pdf file outputs.

However, if I change the line

\pscircle[linecolor=Mahogany](-1, 7){2.4495}

to

\pscircle[linecolor=Mahogany](-1, 7){!6 sqrt}

it does not compile and instead gives me the error message:
*******
! Missing number, treated as zero.
<to be read again>
                    !
l.27 \pscircle[linecolor=Mahogany](-1, 7){!6 sqrt}

?
*******

Can anyone please tell me what I am doing wrong?

Thanks in advance.

--Chandra
   05 Nov 04
------------------
Dr R (Chandra) Chandrasekhar
Department of Mathematics and Statistics
Curtin University of Technology (CUT)
Kent Street, Bentley, WA 6102, AUSTRALIA
Building: 314  Room: 456
Phone: +61-(8)-9266-7623  Fax: +61-(8)-9266-3197
email: r.chandrasekhar at curtin.edu.au
postal mail: GPO Box U1987, Perth, WA 6845, AUSTRALIA
CRICOS Provider Code: 00301J
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