Emil Dotchevski wrote:
I agree that transp is perhaps too short. The q_, v_ and m_traits though shouldn't be a problem since throughout the entire library q, v and m mean the same thing.
Throughout the entire *library*, yes; while you're writing your library I'm sure you don't get confused about what q, v and m stand for. But when they appear in my application, which pulls in maybe a dozen libraries, these short names are incomprehensible. Imagine the scenario where someone picks up some code written by someone else and needs to understand it: they really need to be able to read it without referring to the documentation for an obscure library first.
The ir/iw accessors are for dynamic indexing and are generally optional. You use r and w for read and write access and in that case access to x, y and z can be implemented as specializations.
Yes I'm aware of the template-index-parameter versions. But I was asking about those that take run-time index parameters. For example, consider a matrix-multiplication function; most likely that will use loops and invoke the ir/iw accessors. Have you looked at whether compilers produce respectable code in that case for structs with x,y,z elements?
I'm really not a fan of the old operator% and now operator, syntax. To me, (v,XY) looks like you're forming a row-vector with two elements. Is there a reason why these accessors can't be written with function syntax, i.e. XY(v) ? Or, for matrices, something like element<4,2>(m) rather than (m,A<4,2>) ?
There is (m,A42) actually which seems preferable to element<4,2>(m).
No, (m,A42) is not preferable to element<4,2>(m): - The (...,...) syntax doesn't look like a function invocation, it looks if anything like you're trying to form a row-vector with two elements. - "A" presumably is short for "at", saving one letter of typing at the expense of incomprehensibility. - "42" says forty-two, not 4,2.
There is no good solution for swizzling, unfortunately.
As an aside, I think it would be useful to present a motivation for the "swizzling" operations. I.e. a simple "real" example of why you might want to "swizzle". Also, I find the word "swizzle" a bit odd. To me it means the same as "munge" or "frobnicate" i.e. it's a nonsense-word that you use as a placeholder. I think what you're really doing is often a permutation, and could be named e.g. permuteZYX() - but there are other cases where you're duplicating or removing elements that aren't strictly permutations. Maybe there is some other mathematical term that encompasses that. Regards, Phil.