From: Jonathan Turkanis (technews_at_[hidden])
Date: 2005-03-07 13:48:35
Pavel Chikulaev wrote:
> "Jonathan Turkanis" <technews_at_[hidden]> wrote in message
>> I'd like a library which simplifies the implementation of expression
>> However, I'd like it to be more general than you have outlined.
> More general? Plese tell me what you mean.
See my next comment.
>> For instance I
>> might not want a + -b to be computed as a - b, but I'd like to have
>> this as an option, and not just for this particular sequence of operations.
> If you put LAZY_ALIAS(Matrix_ + -Matrix_ = Matrix_ - Matrix_) then
> a + -b will be computed as a - b, else it won't.
Okay, this certainly wan't clear from you're feature summary. I'll admit I
didn't study the sample usage; this was because the feature summary seemed
Now that I look at your sample, I wonder whether it is possible to support
operators which take instances of different types. This would be essential for
an expression templates library.
>> Also, I don't think it needs to be so heavily macro-based.
> The key feature of the library is to make library usage as simple as
> and macros is the only way (AFAIK) to achieve such simplicity.
> So, do you really think it can be less macro-based and
> more readable at the same time?
> If you have any ideas who do it, please send me how to do it.
Have you considered the approach taken by Boost.Operators?
Also, I believe Fusion (the sucessor to Tuple) would be a valuable tool.
I'm not saying that macros have no place in an expression templates library; in
the iostreams library, a single macro invocation is used to make a Filter usable
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