3 ms·

As someone who actually used to program in PostScript, I am happy as a clam with PDFs! There are two issues with parsing them however. 1) PDF is an output f

by IncRnd 6y ago

As someone who actually used to program in PostScript, I am happy as a clam with PDFs! There are two issues with parsing them however. 1) PDF is an output format and was never intended to have the display text be parseable. 2) PDF is PostScript++, which means that is is a programming language. This means that a PDF is also an input description to the output that we are all familiar with seeing on a page. PS I don't know if it is the case anymore, but Macs used to have a display server that handled all screen images in PDF format. That was an optimization from the NeXT display server, which displayed using Display PostScript.

JadeNB 6y ago
> PS I don't know if it is the case anymore, but Macs used to have a display server that handled all screen images in PDF format. That was an optimization from the NeXT display server, which displayed using Display PostScript. Quartz! https://en.wikipedia.org/wiki/Quartz_(graphics_layer)#Use_of_PDF https://en.wikipedia.org/wiki/Quartz_(graphics_layer)#Use_of...
- IncRnd 6y ago
  AHA! Thank you.
tonyedgecombe 6y ago
>PDF is PostScript++, which means that is is a programming language. The big change that came with PDF was removing the programming capabilities. A PDF file is like an unrolled version of the same PostScript file. There is still a residue of PostScript left but in no way can it be described as a programming language.
- IncRnd 6y ago
  PDF is absolutely a programming language. It is not a general purpose programming language but a page description language. You are referring to looping constructs and procedures being removed, but a loop does not a language make. Similarly, LaTeX and sed are programming languages.
  - tonyedgecombe 6y ago
    What features do you think make it a programming language? Because I have spent quite a bit of time working with it and all I can see is a file format.
    - IncRnd 6y ago
      "A programming language is a vocabulary and set of grammatical rules for instructing a computer or computing device to perform specific tasks." A programming langauge is not inherently a programming language due to features it contains but due to it being used to program. A program is "a series of coded software instructions to control the operation of a computer or other machine." In this way, a PDF file embodies a program that performs specific tasks. A PDF file does not contain a general purpose programming language, but it does contain the page description language of the output format that describes what is to be imaged. Then, the PDF program is given to an interpreter that displays the output. This is the same as a simple program in turtle graphics to display a rectangle, even if no other language feature was used. In such a case, one would say that rectangle was programmed. We would not use the word program in connection with that turtle graphics program, if the rectangle description were not sent to an interpreter that displayed the rectangle.
      - tonyedgecombe 6y ago
        By that definition notepad is a programming language because it can open and show a text document.

by IncRnd 6y ago

JadeNB 6y ago

> PS I don't know if it is the case anymore, but Macs used to have a display server that handled all screen images in PDF format. That was an optimization from the NeXT display server, which displayed using Display PostScript. Quartz! https://en.wikipedia.org/wiki/Quartz_(graphics_layer)#Use_of_PDF https://en.wikipedia.org/wiki/Quartz_(graphics_layer)#Use_of...

IncRnd 6y ago
AHA! Thank you.

tonyedgecombe 6y ago

>PDF is PostScript++, which means that is is a programming language. The big change that came with PDF was removing the programming capabilities. A PDF file is like an unrolled version of the same PostScript file. There is still a residue of PostScript left but in no way can it be described as a programming language.

IncRnd 6y ago
PDF is absolutely a programming language. It is not a general purpose programming language but a page description language. You are referring to looping constructs and procedures being removed, but a loop does not a language make. Similarly, LaTeX and sed are programming languages.
- tonyedgecombe 6y ago
  What features do you think make it a programming language? Because I have spent quite a bit of time working with it and all I can see is a file format.
  - IncRnd 6y ago
    "A programming language is a vocabulary and set of grammatical rules for instructing a computer or computing device to perform specific tasks." A programming langauge is not inherently a programming language due to features it contains but due to it being used to program. A program is "a series of coded software instructions to control the operation of a computer or other machine." In this way, a PDF file embodies a program that performs specific tasks. A PDF file does not contain a general purpose programming language, but it does contain the page description language of the output format that describes what is to be imaged. Then, the PDF program is given to an interpreter that displays the output. This is the same as a simple program in turtle graphics to display a rectangle, even if no other language feature was used. In such a case, one would say that rectangle was programmed. We would not use the word program in connection with that turtle graphics program, if the rectangle description were not sent to an interpreter that displayed the rectangle.
    - tonyedgecombe 6y ago
      By that definition notepad is a programming language because it can open and show a text document.