On Fri, Nov 21, 2014 at 08:31:13AM -0800, Andrei Alexandrescu via Digitalmars-d wrote: > On 11/21/14 6:03 AM, ketmar via Digitalmars-d wrote: > >On Thu, 20 Nov 2014 13:28:37 -0800 > >Walter Bright via Digitalmars-d <digitalmars-d@puremagic.com> wrote: > > > >>On 11/20/2014 7:52 AM, H. S. Teoh via Digitalmars-d wrote: > >>>What *could* be improved, is the prevention of obvious mistakes in > >>>*mixing* signed and unsigned types. Right now, D allows code like > >>>the following with no warning: > >>> > >>> uint x; > >>> int y; > >>> auto z = x - y; > >>> > >>>BTW, this one is the same in essence as an actual bug that I fixed > >>>in druntime earlier this year, so downplaying it as a mistake > >>>people make 'cos they confound computer math with math math is > >>>fallacious. > >> > >>What about: > >> > >> uint x; > >> auto z = x - 1; > >> > >>? > >> > >here z must be `long`. and for `ulong` compiler must emit error.
What if x==uint.max? > Would you agree that that would break a substantial amount of correct > D code? -- Andrei Yeah I don't think it's a good idea for subtraction to yield a different type from its operands. Non-closure of operators (i.e., results are of a different type than operands) leads to a lot of frustration because you keep ending up with the wrong type, and inevitably people will just throw in random casts everywhere just to make things work. T -- We are in class, we are supposed to be learning, we have a teacher... Is it too much that I expect him to teach me??? -- RL
