IBM SC34-5764-01 Parentheses and Operator Precedence

>>= Strictly greater than or equal to
\<<, ¬<<
Strictly NOT less than
<<= Strictly less than or equal to
\>>, ¬>>
Strictly NOT greater than
Note: Throughout the language, the not character, ¬, is synonymous with the backslash (\). Youcan use
the two characters interchangeably, according to availability and personal preference. The
backslash can appear in the following operators: \(prefix not), \=,\==,\<,\>,\<<, and \>>.
Logical (Boolean)
A character string is taken to have the value false if it is 0, and true if it is 1. The logical operators take one
or two such values (values other than 0or 1are not allowed) and return 0or 1as appropriate:
&AND
Returns 1if both terms are true.
|Inclusive OR
Returns 1if either term is true.
&& Exclusive OR
Returns 1if either (but not both) is true.
Prefix \,¬
Logical NOT
Negates; 1becomes 0, and 0becomes 1.
Parentheses and Operator Precedence
Expression evaluation is from left to right; parentheses and operator precedence modify this:
vWhen parentheses are encountered (other than those that identify function calls) the entire
subexpression between the parentheses is evaluated immediately when the term is required.
vWhen the sequence:
term1 operator1 term2 operator2 term3
is encountered, and operator2 has a higher precedence than operator1, the subexpression (term2
operator2 term3) is evaluated first. The same rule is applied repeatedly as necessary.
Note, however, that individual terms are evaluated from left to right in the expression (that is, as soon
as they are encountered). The precedence rules affect only the order of operations.
For example, *(multiply) has a higher priority than +(add), so 3+2*5 evaluates to 13 (rather than the 25
that would result if strict left to right evaluation occurred). To force the addition to occur before the
multiplication, you could rewrite the expression as (3+2)*5. Adding the parentheses makes the first three
tokens a subexpression. Similarly, the expression -3**2 evaluates to 9(instead of -9) because the prefix
minus operator has a higher priority than the power operator.
The order of precedence of the operators is (highest at the top):
+-¬\(prefix operators)
** (power)
*/%//
(multiply and divide)
+- (add and subtract)
(blank) || (abuttal)
(concatenation with or without blank)
REXX General Concepts
118 CICS TS for VSE/ESA: REXX Guide