Variables

A variable has a name and a value. You define or redefine a variable with the sequence sdefine(name, value) or a sequence define(name, value).

• The name of the variable can be up to 32 characters long. The name must begin with an alphabetic character and may contain numbers and alphabetic characters.
• For sdefine(name, value), the value of the variable may be up to 132 characters long. It may contain any characters inside, except for '(\)'. Leading and trailing blanks in the value are ignored.
• For define(name, expr), the value of the variable is value of the arithmetic expression expr.

Whenever gd1 or gd1.pp encounter the name of an already defined variable, the name is substituted by the value of the variable, and the line is interpreted again.