$1 check for first person who convinces me main can't be reserved
Arthur David Olson
ado at elsie.UUCP
Fri Feb 26 05:19:42 AEST 1988
While the check has yet to be claimed, one correspondent has made me realize
that the Catch-22 applying to an "external reserved identifier" also applies
to a "keyword," as witness the following dialogue involving yours truly ("ME")
and an implementer ("IMP"):
ME: My program
main() { return 0; }
doesn't return zero.
IMP: Yeah. . .you misused a keyword.
ME: Huh?
IMP: Main. One of our extensions makes it a keyword.
You're not allowed to use it at all.
ME: What? You can't make that extension! It alters the
behavior of my strictly conforming program!
IMP: Your program isn't strictly conforming. You use a
(extended) keyword, which Section 3.1.1 says you shall
not do. The "shall not" is not in a "Constraint" section.
Section 1.6 says "If a 'shall' or 'shall not' requirement
that appears outside of a constraint is violated, the
behavior is undefined.' And since your program produced
"output dependent on. . .undefined. . .behavior," it isn't
strictly conforming, per Section 1.7.
Providentially, this Catch-22 is even easier to deal with than the
"external reserved identifier" one (with the addition of one word only),
changing the sentence in Section 3.1.1 that begins
The following tokens (entirely in lower-case) are reserved
(in translation phases 7 and 8) for use as keywords. . .
to begin
Only the following tokens (entirely in lower-case) are reserved
(in translation phases 7 and 8) for use as keywords. . .
(You have to add a whole sentence to fix the external reserved identifier
problem.)
--
ado at vax2.nlm.nih.gov ADO, VAX, and NIH are Ampex and DEC trademarks
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