On Sun, 8 Nov 2009 23:16:48 -0600, Joel C. Ewing wrote:
>More explicitly, the JCL reference manual states:
>"Use comparison operators in a relational-expression to compare a
>keyword with a numeric value."
>
>This doesn't directly address the special case where two numeric values
>(after substitution) are being compared - in fact nowhere is it stated
>that comparison of two values where neither is a keyword is a legal
>syntax, although we know from empirical evidence it works with two
>numerics.
>
This is dreadful! If the comparison doesn't work as expected,
IBM's out is to say you broke the rules, but they provide no
error message.
And nearby:
17.1.4.5 "z/OS V1R11.0 MVS JCL Reference"
17.1.4.5 Relational-Expression Keywords
The following keywords are the only keywords supported by IBM and
recommended for use
in relational-expressions. Any other keywords, even if accepted by the
system, are not
intended or supported keywords.
And elsewhere nearby:
17.1.9 Considerations when Using the IF/THEN/ELSE/ENDIF Construct
* You can specify symbolic parameters on IF/THEN/ELSE/ENDIF statements
provided that
they resolve to one of the supported relational-expression keywords
listed in the
preceding topic (that is, RC, ABEND, ...). Any other symbolic
parameters, even if
accepted by the system, are not intended or supported.
So,
// SET X='STEP.RC'
// IF (&X=4) THEN
is apparently supported, but:
// SET Y=4
// IF (STEP.RC=&Y) THEN
is unsupported.
Both the JCL parser and the doc should mutually be revised so that
all constructs "accepted by the system" are described as "supported"
and/or constructs not described as "supported" such as the OP
attempted result in JCL errors.
A BNF syntax diagram would be useful here.
-- gil
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