# [pstricks] Bug: pst-tree generates invalid PostScript code

Denis Girou Denis.Girou at idris.fr
Sat May 18 20:48:52 CEST 2002

>>>>> "Edward.Avis" == Edward Avis <epa98 at doc.ic.ac.uk> writes:

Edward.Avis> I've found that certain characters in node labels and the like can cause
Edward.Avis> pst-tree to generate PostScript specials which crash the PostScript
Edward.Avis> interpreter.  Minimal test case:

Edward.Avis> \documentclass{article}
Edward.Avis> \usepackage{pst-tree}
Edward.Avis> \begin{document}
Edward.Avis> \pstree{\TC[name=()]}{}
Edward.Avis> \end{document}

Edward.Avis> This runs through 'latex' and 'dvips' just fine but the resulting PS
Edward.Avis> file is not valid.  Replacing the () characters with something like 'ab'
Edward.Avis> works fine.

Edward.Avis> IMHO pstricks ought to quote these characters in some way so that they
Edward.Avis> don't cause PostScript syntax errors - or at least give a warning when
Edward.Avis> processing the file.

Your remark is obviously true. Nevertheless, I do not believe that we can
change anything. This behavior is clearly documented and this restriction has
no ambiguity. Refer to the page 7 of the so-called Beta documentation (which
replace the same explanation of the page 59 of the documentation of the
version 0.93): "The name must contain only letters and numbers, and must begin
with a letter. Bad node names can cause PostScript errors." This rule is not
recalled on page 42 when the "name" parameter is discussed inside trees, but
readers must clearly have the informations relative on nodes in mind at this
point.

Reread too the end of the page 1 and the beginning of the page 2 of the
documentation of version 0.93. It clearly state that in some cases the
PostScript errors are not cheched at the TeX level and will be diagnosed only
by the PostScript interpreters. I can imagine that this is for cases where
error detection would be really difficult to do or too consuming.

D.G.