CODEWITHSUNDEEP
postscript
Jason
Jason

Reputation: 39

Postscript syntax difficulty

Having difficulty trying to create a postscript file that will output differently based on a string at the beginning. I'm able to do the following and create a valid postscript file:

/x (string) def

  /Times-Roman findfont
  12 scalefont
  setfont
  newpath
  100 200 moveto
  (sdbc) show

Then, I try to wrap an if statement around it...

/x (string) def

x (string) eq {
  /Times-Roman findfont
  12 scalefont
  setfont
  newpath
  100 200 moveto
  (sdbc) show } if

And this creates an invalid postscript file. Any tips on postscript syntax to achieve this kind of thing would be greatly appreciated!

I'm using Document Viewer on ubuntu which I believe is used as the interpreter.

Upvotes: 3

Views: 241

Answers (2)

Jason
Jason

Reputation: 39

It was ubuntu's document viewer - it is very touchy. Try using ghostscript if you run into this problem.

Upvotes: 0

KenS
KenS

Reputation: 31139

String (and other composite) objects are the same only if they are the same object, not if their contents are the same. In C terms they are equivalent only if they are the same pointer.

So:

/x (string) def
/y x def
/Z (string) def

y equals x, z does not equal either x or y. If you want to test for the contents of the strings being the same, then you need to examine the character at each position individually using the get operator, there is no strcmp or similar operator.

The behaviour of composite objects is is an important and often overlooked point in PostScript.

Upvotes: 2

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