That is true, but the convention exists nonetheless. Consider, for example, this branch of the combinatorics literature: http://en.wikipedia.org/wiki/Square-free_word
-- John On Jul 3, 2014, at 8:09 AM, yi lu <zhiwudazhanjiang...@gmail.com> wrote: > I know abstract algebra. When talking about string concatenation, a 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, 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. >> >> >> >> > >
