Re: makempy (pstoedit <-> gs) hangs

[Arthur Reutenauer <arthur.reutenauer@normalesup.org>]

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  I think I've identified the problem: in the PostScript prologue file for
pstoedit you find the following bit of code (slightly simplified):

	/getorigfont
	{
	  dup /OrigFont known
	  {
	    /OrigFont get getorigfont
	  }
	  if
	}
	def


  I guess anyone, even not familiar with PostScript, can spot the error here:
getorigfont is called recursively ad infinitum! I have no idea why this is so,
but this mistake is easy to correct, by simply commenting out the innermost
“getorigfont”; and it indeed fixes the problem with Wolfgang's code.

  Why the error wouldn't happen with older versions of gs isn't clear to me and
I haven't tested it (for debugging I used pstoedit 3.44 and gs 8.56
throughout); on the other hand, it's quite clear why the bug wouldn't show up
on code that uses only outlines and no font, like in the last example of
http://wiki.contextgarden.net/User-Defined_Enumerations as George pointed out:
the spurious piece of code is only used for font redefinitions and is therefore
not called in the case of the fuzzy itemize style, because the symbols are not
taken from a font.

  For people wanting to compile an amended version of pstoedit, the attached
patch should do the trick, although hand-editing the relevant file
(src/pstoedit.ph) should be just as easy (this is really a 2-byte patch — and
you can even turn it into a 2-bit patch ;-).


>                                                       Since pstoedit
> mucks with ghostscript's SYSTEMDICT it isn't surprising that problems
> arise for newer gs versions.

  That's what I thought too (even if the bug had nothing to do with that
apparently). I wonder if all that is really needed and if it wouldn't be
simpler and less error-prone to use a custom dictionary where all the
overriding functions are defined. Instead the author of pstoedit does quite
scary things with systemdict ...

>                               Maybe it is time for ghostscript to get
> an mpost driver.

  Sure, wouldn't harm either.

	Arthur

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diff -cNrp pstoedit-3.44/src/pstoedit.ph pstoedit-3.44-patched/src/pstoedit.ph
*** pstoedit-3.44/src/pstoedit.ph	Mon Jul 30 00:35:24 2007
--- pstoedit-3.44-patched/src/pstoedit.ph	Mon Jul 30 00:34:29 2007
*************** const char * const PS_prologue[] = 
*** 1920,1926 ****
   " { 210 pscover ",
   " dup /OrigFont known ",
   " { 211 pscover ",
!  " /OrigFont get getorigfont  ",
   " }  ",
   " if ",
   " }  ",
--- 1920,1926 ----
   " { 210 pscover ",
   " dup /OrigFont known ",
   " { 211 pscover ",
!  " /OrigFont get % getorigfont  ",
   " }  ",
   " if ",
   " }  ",

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