On 11/14/2011 09:51 PM, Brad Anderson wrote:
On Mon, Nov 14, 2011 at 1:29 PM, Timon Gehr <timon.g...@gmx.ch <mailto:timon.g...@gmx.ch>> wrote:On 11/14/2011 08:47 PM, Andrei Alexandrescu wrote: On 11/14/11 1:15 AM, Timon Gehr wrote: Looks good, I think this is the right direction. Nitpicks: 1. // Type deduction works for function results. This is important for generic // functions, such as min below, which works correctly for all comparable // types. auto min(T1, T2)(T1 lhs, T2 rhs) { return rhs < lhs ? rhs : lhs; } It does not. The two types need to have a common type as well. It's difficult to be concise and complete simultaneously. The underlying assumption is that if two types are comparable, they also have a common type. hm, maybe call the them 'compatible comparable types'? 2. The scope statement example should actually show transactional code. Otherwise the poor reader feels fooled into clicking "See example". Using scope(exit) to write something at function exit is useful for debugging, but scope(failure) is the real thing that is important to show. Good point. 3. If contract inheritance is to be promoted on the front page (and it is certainly something that may attract developers), it should actually work. Absolutely. There has been disagreement on whether or not my bug report on the matter was valid. What it means for your example: // Interfaces and classe interface Printable { void print(uint level) in { assert(level > 0); } // contract is part of the interface } // Interface implementation class Widget : Printable { void print(uint level) { ... } } void main(){ Widget w = new Widget(); w.print(0); // passes through, but should not } Can you state in the issue tracker that the bug report is valid? http://d.puremagic.com/issues/__show_bug.cgi?id=6856 <http://d.puremagic.com/issues/show_bug.cgi?id=6856> 4. If we can find a less buzzy word than 'Multi-paradigm power' to describe D's multi-paradigm power, that would be nice, but I am also fine with the current state of affairs. 5. The most important language features are not displayed at all. Where are Metaprogramming, CTFE and code generation? It sure is hard to come up with a short but convincing example, but I think we should try to. Those would be under the multi-paradigm thingie. Ok. Maybe there could be a few LOC demonstrating the 'recurrence' function generating a few fibonacci numbers. I think it is a nice showcase, although I have never needed that particular function in real code :o). It has also the potential of showing Phobos' lazy functional style features. But unfortunately, most functional programmers will shriek for a moment when they see the argument order of 'take'. I think that's a good idea. While learning D I became impressed with it when I solved Project Euler problem 2 ("By considering the terms in the Fibonacci sequence whose values do not exceed four million, find the sum of the even-valued terms.") with: auto answer = reduce!"a + b"(filter!"a % 2 == 0"(until!"a > 4_000_000"(recurrence!"a[n-1] + a[n-2]"(1, 1)))); It'd look better with UFCS but it's still rather neat I think.
You can also use stride(..., 3) instead of filtering.
