----- Original Message ----- From: "David Abrahams" <[EMAIL PROTECTED]>
> >> BTW, IIF always bothered me when I saw it; it's non-memnonic, and I > >> never knew what it did. IF_BOOL would have been better in that > >> respect. > > > > It stands for "inline if" because it is doesn't do any checking. The > > condition *must* be 1 or 0 period. BOOST_PP_IF is implemented in terms of > > BOOST_PP_IIF, but using BOOST_PP_IF when the condition is guaranteed to be 0 > > or 1 is a waste of time. > > I understand what you're saying, but I think "inline if" doesn't > reflect what it's doing and IIF is still not memnonic. It ultimately from (don't laugh) VB's version of the ternary operator--called "iif." It is not semantically exactly the same, but it is "similar" in the C++ inlining sense. For better or for worse, that is its name. > > If you used (?) instead, it would absolutely force you to use (?) to > > complete the ternary conditional. The point of using it somehow, is to > > enforce that it isn't this: (aaaaaaaaaaaaaa) <= 0x1234 -- if I don't use > > it, I can't tell the difference between '?', '!', and 'aaaaaa'. > > Yes, but that would force inversion of the conditional, which would > look weird. Inversion? You'd just have to swap the 1 and 0: "expr ? 0 : 1" versus "expr ? 1 : 0". > > The PP lib uses no other libraries. It won't even use this one. This is > > primarily because the concerns are different in the PP-lib. The bugs in > > VC++ and Metrowerks are ones that break encapsulation. The resulting fix is > > to implement the workarounds over the entire library has a whole. The > > aren't specific enough to localize that cleanly. I also consider the PP lib > > to pontentially be *the* base-level library on a library dependency scale. > > I like reuse, but only if it is "downward" reuse. I.e. The preprocessor lib > > doesn't use the MPL, but the MPL uses the preprocessor lib; the MPL doesn't > > use library X, but library X uses the MPL. I think this reuse ordering > > models the phases of translation (including runtime). > > I have no problem with it, but I'd like to hear at least one more > opinion (other than Gennaro's) before we move forward with it. This > macro will be used in every Boost library, so if people find it > terribly odious it will be a failure. I'm not asserting that it should be done this way. Rather, I'm just saying that this (or something similar) is possible if that is what you want. It seems like a total overkill to me. The benefit does not pay for the implied complexity. On the plus side, it is clever ;) and yields a clean syntax. However, I still think that the use of the pp-lib is fine and represents an acceptable dependency, but in this particular case, it's overdoing it--IMHO. Paul Mensonides _______________________________________________ Unsubscribe & other changes: http://lists.boost.org/mailman/listinfo.cgi/boost
