A character string expression can be used for any parameter, element, or qualifier defined with EXPR(*YES) in the command definition object.
Any expression can be used as a single parameter in the Change Variable (CHGVAR) and If (IF) commands. An expression in its simple form is a single constant, a variable, or a built-in function. An expression usually contains two operands and an operator that indicates how the expression is to be evaluated. Two or more expressions can be combined to make a complex expression.
The following types of expressions are supported in CL programs:
A complex expression contains multiple operands, operators that indicate what operation is performed on the operands, and parentheses to group them. Only one operator is allowed between operands, except for the + and - signs when they immediately precede a decimal value (as a signed value), and the *NOT operator when it is used in a logical expression.No complex expression can have more than five nested levels of parentheses, including the outermost (required) level.
Arithmetic and character string expressions can be used together in a complex expression if they are used with relational and logical operators; for example: (A=B&(1+2)=3). A pair of arithmetic expressions or a pair of character string expressions can be compared within a relational expression. Also, relational expressions can be used within a logical expression