Examine vs Inspect
William M. Klein
***
ANSI X3.23-1974, Appendix A, The History of COBOL, has the following:
Page XIV-11, 2.3.2, Overview of the Revised Module under 2.3, Differences
between X3.23-1968 and the Revised Standard: "The EXAMINE statement has been
deleted in favor of the more general and powerful INSPECT statement. The
INSPECT statement provides the ability to count (Format 1), replace (Format 2)
or count and replace (Format 3) occurrences of single characters or groups of
characters in a data item."
Page XIV-29, 2.3.3, Substantive changes, item 49: "EXAMINE statement and the
special register TALLY were deleted." This entry carries the indication that
existing programs may be affected and the remark "Function was replaced by the
INSPECT statement." Item 50 contains a "condensed" version of the description
of INSPECT from 2.3.2.
EXAMINE is listed among items deleted from the revised standard on page XIV-31
under 2.3.4, simply indicating that it is replaced by the more powerful INSPECT.
I suspect one of the reasons for using a different verb (INSPECT vs. EXAMINE)
was to eliminate any possible ambiguity arising from the fact that EXAMINE ...
TALLYING affected a special register (TALLY) in '68; this register was
eliminated in favor of user-specified data items in the TALLYING forms of
INSPECT. Also, EXAMINE tallied everything into TALLY as I recall, which means
that doing multiple tallies in a given EXAMINE was, if not impossible, at least
no more than marginally useful. Allowing separate data items with INSPECT
eliminated that restriction. This is in addition to the ability to combine
TALLYING and REPLACING, or both, in a single INSPECT, which the '74 standard
indicates wasn't legal in '68.
***
FYI, as long as I have been following COBOL there has been a "direction" to get
rid of (and avoid adding) special registers (and figurative constants). For
example, in those implementations that first introduced "length of" it created a
special register, but this was NOT how it was added in Standard COBOL. (Same
for ADDRESS OF and NULLS figurative constant)
--
Bill Klein
wmklein <at> ix.netcom.com
LX-i
> I asked in J4 and here is the information that I received back.
[snip]
> I suspect one of the reasons for using a different verb (INSPECT vs. EXAMINE)
> was to eliminate any possible ambiguity arising from the fact that EXAMINE ...
> TALLYING affected a special register (TALLY) in '68; this register was
> eliminated in favor of user-specified data items in the TALLYING forms of
> INSPECT. Also, EXAMINE tallied everything into TALLY as I recall, which means
> that doing multiple tallies in a given EXAMINE was, if not impossible, at least
> no more than marginally useful. Allowing separate data items with INSPECT
> eliminated that restriction. This is in addition to the ability to combine
> TALLYING and REPLACING, or both, in a single INSPECT, which the '74 standard
> indicates wasn't legal in '68.
Ah - that makes sense. There were a few programs that still had
references to registers in them when I got to my first shop, and I never
did figure out what that was for - that must be what one of them was. :)
> FYI, as long as I have been following COBOL there has been a "direction" to get
> rid of (and avoid adding) special registers (and figurative constants). For
> example, in those implementations that first introduced "length of" it created a
> special register, but this was NOT how it was added in Standard COBOL. (Same
> for ADDRESS OF and NULLS figurative constant)
That's a good thing, IMO. With user defined data names, you know
exactly what you've got.
I really appreciate this detailed information. :) Thanks!
--
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