== Bahasa ==
PostScript is a [[Turing-complete]] programming language, belonging to the [[concatenative programming language|concatenative]] group. Typically, PostScript programs are not produced by humans, but by other programs. However, it is possible to write computer programs in PostScript just like any other programming language.
PostScript is an interpreted, [[Stack-oriented programming language|stack-based]] language similar to [[Forth (programming language)|Forth]] but with strong dynamic [[Type system|typing]], data structures inspired by those found in [[Lisp programming language|Lisp]], [[scoped memory]] and, since language level 2, [[Garbage collection (computer science)|garbage collection]]. The language syntax uses [[reverse Polish notation]], which makes the order of operations unambiguous, but reading a program requires some practice, because one has to keep the layout of the [[Stack (data structure)|stack]] in mind. Most ''operators'' (what other languages term ''functions'') take their arguments from the stack, and place their results onto the stack. ''[[Literal (computer science)|Literal]]s'' (for example numbers) have the effect of placing a copy of themselves on the stack. Sophisticated data structures can be built on the ''array'' and ''dictionary'' types, but cannot be declared to the type system, which sees them all only as arrays and dictionaries, so any further typing discipline to be applied to such user-defined "types" is left to the code that implements them.
The character "%" is used to introduce comments in PostScript programs. As a general convention, every PostScript program should start with the characters "%!" so that all devices will properly interpret it as PostScript.