# How can I use unicode characters as identifiers in PostScript? Is it impossible?

I feel "uncomfortable" with the existing constants below (which are already defined in PSTricks)

Euler = 2.718281828
Pi = 3.141592654


because I think using e and π is much more natural.

My question is : How can I use unicode characters as identifiers in PostScript? Is it impossible?

\documentclass[pstricks,border=12pt]{standalone}

\usepackage{pst-plot}
\pstVerb
{
/e {2.718281828} def
/π {3.141592654} def
}

\def\f{ln(e^x)+π}

\begin{document}
\begin{pspicture}[algebraic](0,-2)(5,5)
\psplot{0}{4}{\f}
\end{pspicture}
\end{document}

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I think the answer is no, you can't do this. According to page 25 of the Postscript Language Reference Manual

There are three encodings for the PostScript language: ASCII, binary token, and binary object sequence.

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Sorry, Is π (ALT+227) ASCII? –  kiss my armpit Jul 14 '14 at 19:53
@Pleasedon'ttouch --- I don't think so. –  Ian Thompson Jul 14 '14 at 19:59
@Pleasedon'ttouch Alt 247 is presumably some input convention in your system but pi is unicode U+03C0 (decimal 960) which isn't in the 0-127 ASCII range. –  David Carlisle Jul 14 '14 at 20:18