In a recent note, john gilmore said:
> Date: Mon, 9 Oct 2006 13:17:52 +0000
>
> Perlis's three-pronged formulation:
>
> A programming language provides mechanisms for
>
How do I shoehorn JCL into this?
> o identifying a data type or data types,
>
The data types I see are:
- Data sets
- The condition code
- (I'll exclude the SET symbols for reasons below).
> o specifying operations on them, and
>
- Utility programs such as IEBGENER, which perform operations
on data sets and set the condition code.
> o speciifying a path or paths of control among these operations,
>
- COND= and IF.
- But these don't affect SET, the only operation on SET symbols,
so I exclude them from the data types.
> has not been improved upon in, now, forty odd years; and it seems unlikely
> that it will be possible to replace it with a more perspicuous formulation
> anytime soon.
>
I see two important omissions here:
- If the path of control can not vary depending on values of the
data types, it's an unacceptable weakness.
- Lack of a facility for iteration (or, equipotentially, recursion)
impoverishes unacceptably the set of control paths. Here JCL fails.
> On Perlis's formulation LISP is a programming language.
>
And COBOL readily is. I'm confident also that a Turing machine
could be emulated in COBOL. Surely no technical case for Google's
omission of COBOL has been made in this thread.
-- gil
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