REXX Features
Some features of REXX that you can use to write more intricate procedures
will be discussed in this section. You will see how to have a procedure
make decisions by testing a value with the IF instruction. You will also
see how to compare values and determine if an expression is true or false.
A brief description of the terms covered in this section follows below:
IFReference
Used
with THEN. Checks if the expression is true. Makes a decision about a
single instruction.
THENReference
Identifies the instruction to be run if the
expression is true.
ELSEReference
Identifies the instruction to be run if the
expression is false.
SELECTReference
Tells the interpreter to select one of a number
of instructions.
WHENReference
Used with SELECT. Identifies an expression
to be tested.
OTHERWISEReference
Used with SELECT. Indicates the instruction
to be run if expressions tested are false.
DO-ENDReference
Indicates that a group of instructions should
be run.
NOPReference
Indicates that nothing is to happen for one
expression.
ComparisonsReference
> < =
Indicates greater than, less than,
equal to.
NOT OperatorReference
í■ or \
Changes the value of a term from true
to false, or from false to true.
AND OperatorReference
&
Gives the value of true if both terms
are true.
OR OperatorReference
|
Gives the value of true unless both terms
are false.
[Back: Writing a REXX Arithmetic Procedure]
[Next: Making Decisions(IF THEN)]