Tracing Results
To trace only the final result of an expression, use the TRACE R (TRACE Results)
form of the TRACE instruction. All expressions that follow the instruction are
analyzed and the results are displayed as:
>>> Final result of an expression
If you changed the TRACE instruction operand in the previous example from an I to
an R, you would see the following results.
9*-*IFx+1>5*y
>>> "0"
In addition to tracing operations and results, the TRACE instruction offers other
types of tracing. For information about the other types of tracing with the TRACE
instruction, see z/OS TSO/E REXX Reference.
Exercises - Using the TRACE Instruction
Write an exec with a complex expression, such as:
IF(A>B)|(C<2*D)THEN ...
Define A, B, C, and D in the exec and use the TRACE I instruction.
ANSWER
Possible Solution
/****************************** REXX *******************************/
/* This exec uses the TRACE instruction to show how an expression */
/* is evaluated, operation by operation. */
/*******************************************************************/
A=1
B=2
C=3
D=4
TRACE I
IF(A>B)|(C<2*D)THEN
SAY 'At least one expression was true.'
ELSE
SAY 'Neither expression was true.'
When this exec is run, you see the following:
Tracing Expressions with the TRACE Instruction
38
z/OS V1R1.0 TSO/E REXX User’s Guide
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