On Feb 4, 2016, at 3:03 PM, Joel C. Ewing wrote:
On 02/04/2016 12:52 PM, Ed Gould wrote:
http://destinationz.org/Mainframe-Solution/Trends/What-the-Heck-Is-
JCL-and-Why-Does-It-Look-So-Funny
What the Heck Is JCL and Why Does It Look So Funny?
It’s important to give job control language its due respect helping
others
- See more at:
http://destinationz.org/Mainframe-Solution/Trends/What-the-Heck-Is-
JCL-and-Why-Does-It-Look-So-Funny#sthash.TRwMFSIg.dpuf
The article starts with a Fred Brooks quote about JCL being the
"worst
computer programming language ever devised", which if you class it as
such is probably true. Job Control Language is indeed an artificial
language, but I wouldn't dignify it by calling it a programming
language. Syntax is only part of the problem: even after enhancements
over the years, there is still no run-time looping capability, very
marginal conditional logic support, and painfully limited variable
support. While it's true that JCL can execute any arbitrary program,
the interfaces between the JCL and those programs is also very
limited,
greatly restricting what an invoked program can do to enhance the
capability of the JCL language itself.
Looping is there but not necessarily in the same set of JCL. One only
has to feed the intrdr and walla you can loop .
Rf
Except for implementation limits on storage and array sizes, finite
external file space, and practical limitations on execution time,
programming languages like FORTRAN, COBOL, PL/I, Algol, Ada, etc.
could
all be used to program a Universal Turing Machine and in theory solve
any computable problem, so you could envision these languages as all
having a some degree of functional equivalency. Without loops, decent
conditional logic, arrays, or reasonable variable types JCL is
unable to
play in that league. There is a good reason why JCL is not normally
regarded as a "Programming" language.
Err what is ifthen, else is classic logic and as I mentioned earlier
you can feed the intrdr to do another task of if you want to get
original BPXBATCH can start another address space.
This is "relatively" new so its not surprising the author didn't
mention it surprising .
Ed
--
Joel C. Ewing, Bentonville, AR [email protected]
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