PostScriptType

PostScriptType is a term used to describe the runtime type classification of objects in the PostScript language. It refers to the kind of data value an object represents while a program executes, rather than to a separate static type system. PostScript is dynamically typed, so type information is determined at run time and is used by the interpreter to apply appropriate operations to values.

In PostScript, objects can belong to several basic types, including integers, real numbers, booleans, strings, names, arrays, dictionaries, procedures, files, and special objects such as marks and the null object. The exact set of type names is exposed to the programmer via the type operator, which queries an object and returns its type as a PostScript name. For example, the type of an integer might be reported as integer, the type of a string as string, and the type of an array as array. The type of a name object would be name, and the type of a dictionary would be dict.

The type operator is typically used for runtime type checking and defensive programming. A common pattern is to push an object, call type, and then compare the result with a known type name to decide how to proceed. Because PostScript is stack-based and dynamically typed, type information is an essential tool for ensuring operands are appropriate for given operators and for implementing conditional logic.

PostScriptType, as a concept, emphasizes how PostScript objects carry intrinsic type information that guides interpretation and execution. It is described in the PostScript Language Reference and related documentation, where the type operator and the set of recognized types are defined. See also: type operator, PostScript language, dynamic typing.