HaloO, Mark J. Reed wrote:
For the record, I am opposed to any restriction on operator overloading that requires mathematical properties to hold. ANYTHING is fair if you predeclare.
Hmm, my idea is more about defining interfaces that allow to detach implementation of (numerical) algorithms from datatypes. E.g. the Euclidean algorithm to find the gcd requires division and a remainder that decreases in absolute value. This is like sorting objects that do the Ordered role.
Besides, there is nothing that inherently associates the "/" symbol with division - it's only an ASCII approximation of fraction notation.
We all know that ASCII is a rather limited char set but one that has the widest support. Unicode has got U+2215 and U+2044 for division and fraction composition.
I want to be able to define / as a path constructor and not give a flying flip that (path 2) * (path 3) / (path 5) - whatever the heck * might mean on paths - is not the same as (path 2) / (path 5) * (path 3).
We need to distinguish two fundamentally different things here. Symbol overloading which is a parser feature and operator overloading that is runtime dispatch unless the compiler has enough information to avoid it. Using / for paths has several drawbacks. First, it is not the universal directory separator, \ is in widespread use also. Second, a path is much more like a string than a number. Third, you have to make sure that at least one of the concatenated types is a Path so that you are dispatching to the intended implementation. Instead of overloading ~ for paths I think inventing ~/ or ~\ as path concatenating operators is well in line with the Perl 6 operator set. And ~. could be the extension concatenator. And I also feel that overloading ~ for file concatenation or photo stitching is good practice. BTW, operator overloading does not allow to change the precedence, associativity and commutativity of the operator because these are parser features. We already had the issue of overloading / with div for Int operants. And IIRC the conclusion then was that / is a Num operator and thus 2/3 != 0 but 2/3 == 0.6666.
The P in Perl stands for Practical, not Pedantic.
I consider well designed interfaces as practical not pedantic ;) Regards, TSa. -- The Angel of Geometry and the Devil of Algebra fight for the soul of any mathematical being. -- Attributed to Hermann Weyl
