Please read my email about why * is not good for string concatenation. Then reread the same email replacing * with +.
On Thu, Jul 3, 2014 at 11:09 AM, yi lu <zhiwudazhanjiang...@gmail.com> wrote: > I know abstract algebra. When talking about string concatenation, a monoid > <http://en.wikipedia.org/wiki/Monoid> is enough. It is true that in a > ring, "+" is a commutative operator, and "*" no commutative required, > however, a ring is far beyond what needed to do a string concatenation job. > > > On Thu, Jul 3, 2014 at 10:59 PM, John Myles White < > johnmyleswh...@gmail.com> wrote: > >> This is just the standard convention in mathematics. See just about any >> textbook on abstract algebra for a discussion of the reasons. >> >> I think it's safe to say that `+` will never be string concatenation, so >> it's better to focus energy on other proposals. >> >> -- John >> >> On Jul 3, 2014, at 7:57 AM, yi lu <zhiwudazhanjiang...@gmail.com> wrote: >> >> @John I know that "*" means no commutative, but I see no reason "+" has a >> meaning of commutative. >> >> >> On Thu, Jul 3, 2014 at 10:53 PM, Stefan Karpinski <ste...@karpinski.org> >> wrote: >> >>> That's even worse. >>> >>> >>> On Thu, Jul 3, 2014 at 10:52 AM, yi lu <zhiwudazhanjiang...@gmail.com> >>> wrote: >>> >>>> I will vote for "+", although I learn mathematics. Maybe that is why I >>>> am not a mathematician. >>>> >>>> Yi >>>> >>>> >>>> On Thu, Jul 3, 2014 at 10:45 PM, Stefan Karpinski <ste...@karpinski.org >>>> > wrote: >>>> >>>>> On Thu, Jul 3, 2014 at 9:42 AM, Ivar Nesje <iva...@gmail.com> wrote: >>>>> >>>>>> We should really create a simple system where you can get those hints >>>>>> printed in the REPL, without defining more methods. >>>>> >>>>> >>>>> Yes, I think we should really pursue this avenue. >>>>> >>>>> For what it's worth – and perhaps something since I'm the original >>>>> perpetrator of the str*str concatenation syntax – I've come to regret this >>>>> operator choice. My reasoning at this point is that we want our operators >>>>> to have fairly "pure" meanings. I chose str*str because concatenation can >>>>> be viewed as a kind of multiplication in the ring of string patterns >>>>> (alternation in the regex sense is the addition operation, the empty >>>>> string >>>>> is the unit and the non-matching pattern is the zero). However, many >>>>> operations can be viewed as a form of multiplication. In the max-plus >>>>> algebra <http://en.wikipedia.org/wiki/Max-plus_algebra>, for example, >>>>> addition is the multiplication operator. So, at this point I think we >>>>> should stick to very pure classical meanings for operators in Base – the >>>>> Base.* function should be just addition of numbers in the classical sense, >>>>> not the broader sense of addition in any conceivable ring. >>>>> >>>>> >>>> >>> >> >> >
