/errtrap_inch {72 mul} bind def
/errtrap_scratch 256 string def
/errtrap_stringshow {errtrap_scratch cvs show} bind def
/errtrap_dshow {dup type dup cvlit userdict exch known
 {exec} {cvlit show pop} ifelse} bind def
/arraytype {([ ) show {errtrap_dshow ( ) show} forall (]) show} def
/dicttype {(--dictionary--) show} def
/fonttype {(--font--) show} def
/gstatetype {(--gstate--) show} def
/locktype {(--lock--) show} def
/marktype {(--mark--) show} def
/filetype {(--filestream--) show} def
/nulltype {(--null--) show} def
/stringtype {(\() show show (\)) show} def
/packedarraytype {(--packedarray--) show} def
/savetype {(--savedstate--) show} def
/booleantype {errtrap_stringshow} def
/integertype {errtrap_stringshow} def
/nametype {errtrap_stringshow} def
/operatortype {errtrap_stringshow} def
/realtype {errtrap_stringshow} def
errordict begin
 /handleerror {
  showpage % spit out the current page "as is"
  /Helvetica-Narrow 8 selectfont % easily distinguishable font
  .5 errtrap_inch 10 errtrap_inch moveto % top left of the page
  $error {gsave exch errtrap_stringshow (: ) show
    errtrap_dshow % show each element
  currentpoint grestore 10 sub % subtract from y coordinate
   currentpoint pop exch moveto pop} % move to next line down
  forall showpage} def
end