6.2.1.2 Argument Units

Some commands take integer arguments that are assumed to represent values in a measurement unit, but the letter for the corresponding scaling unit is not written with the output command arguments. Most commands assume the scaling unit ‘u’, the basic unit of the device, some use ‘z’, the scaled point unit of the device, while others, such as the color commands, expect plain integers.

Single characters can have the eighth bit set, as can the names of fonts and special characters. The names of characters and fonts can be of arbitrary length. A character that is to be printed is always in the current font.

A whitespace character (space, tab, or newline) always terminates a string argument. A ‘#’ character embedded in a string argument is part of that argument, not the beginning of a comment command. Any character other than a decimal numeral terminates a command that mtakes a numeric argument, and, if not whitespace, is interpreted as the start of a new command.