| Roger While 2007-08-28, 6:55 pm |
|
"Karl Kiesel" <Karl.Kiesel@fujitsu-siemens.com> schrieb im Newsbeitrag
news:fb115t$6kc$1@nntp.fujitsu-siemens.com...
> "William M. Klein" <wmklein@nospam.netcom.com> schrieb im Newsbeitrag
> news:e4EAi.169153$Bo7.88986@fe07.news.easynews.com...
> Bill,
> that is just the problem I see here! The STD2002 defines a sequence of
> separate stages of compilation (see chapter 7) but the earlier stage (text
> manipulation) may need information that can only be obtained from the
> later stage (compilation): expressions within >>IF and >>EVALUATE
> directives may be formed using literals (for example see STD2002 7.2.7.1
> syntax rule 1) and i did not find any rule, that forbids using a constant
> in place of a literal in these expressions. Therefore, to complete the
> text manipulation stage, a compiler must be able to evaluate constant
> conditional expressions in directives, but this is impossible, if a
> constant is involved, beause processing (ie recognition and especially
> determining the value) of such a constant entry is definitely part of the
> later stage - but this stage can not be entered unless the previous stage
> has been completed! In this sense, using constants within directives is a
> form of 'forward reference'; If the concept of stages within the STD2002
> is to be kept - and I would not like to give it up! - constant entries are
> a problem that make implementaion rather hard, if not impossible.
>
> Karl Kiesel
> Fujitsu Siemens Computers
>
>
Geez, you beat me to it. I had studied the standard for the last
x hours/days. I had come to the conclusion as you did.
I was still trying to find the reverse arguments.
Incidentally a GLOBAL CONSTANT is somewhat different
in that it has to abide by the GLOBAL constraint.
ie. This is only possible to refernce backwards.
Roger
Roger
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