Preface - Adobe

CHAPTER 3
Arrays
32
Language
The characters [ and ] are self-delimiting tokens that specify the construction of
an array. For example, the program fragment
[ 123 /abc (xyz) ]
results in the construction of an array object containing the integer object 123,
the literal name object abc, and the string object xyz. Each token within the
brackets is executed in turn.
The [ and ] characters are special syntax for names that, when executed, invoke
PostScript operators that collect objects and construct an array containing them.
Thus the example
[ 123 /abc (xyz) ]
contains these five tokens:
• The name object [
• The integer object 123
• The literal name object abc
• The string object xyz
• The name object ]
When the example is executed, a sixth object (the array) results from executing
the [ and ] name objects.
Procedures
The special characters { and } delimit an executable array, otherwise known as a
procedure. The syntax is superficially similar to that for the array construction operators
[ and ]; however, the semantics are entirely different and arise as a result of
scanning the procedure rather than executing it.
Scanning the program fragment
{add 2 div}