Re: Why Does Dscanner Warn About a Missing toHash if opEquals is Defined?
On Sunday, 31 July 2016 at 18:57:50 UTC, Jack Stouffer wrote: Next question: what's the fastest hashing implementation that will provide the least collisions? Is there a hash implementation that's perfered for AAs? I've heard that FNV-1a is a decent general-purpose option, and it's fairly straightforward. https://en.wikipedia.org/wiki/Fowler%E2%80%93Noll%E2%80%93Vo_hash_function
Re: Why Does Dscanner Warn About a Missing toHash if opEquals is Defined?
On Sunday, 31 July 2016 at 16:39:59 UTC, Jack Stouffer wrote:
But D provides a default toHash for every type if it's not
defined. I was wondering why not just rely on that version.
If two objects are equal, their hashes must also be equal.
Consider this example:
struct Nullable(T) {
bool isNull;
T value;
bool opEquals(Nullable!T other) {
if(this.isNull != other.isNull) return false;
// Any two nulls are equal.
if(isNull) return true;
return this.value == other.value;
}
}
auto n1 = Nullable!int(true, 3);
auto n2 = Nullable!int(true, 4);
writeln(n1 == n2); // true
writeln(n1.hashOf == n2.hashOf); // false = BAD!
Now that I think about it, maybe this should be in the language
docs; I don't think they mention it.
(https://dlang.org/spec/operatoroverloading.html#equals)
Re: Iterate all visible symbols, even from imported modules
On Monday, 18 July 2016 at 13:00:16 UTC, Lodovico Giaretta wrote: // how do I discover that "std" is a package? I've got a DMD pull request that adds __traits(isPackage, someSymbol), but it's stuck waiting for approval. If and when it gets merged, it could be useful for that. https://github.com/dlang/dmd/pull/5290
Keeping a reference to a linked list element
I just started working on a project in which it would be convenient to hold a reference to a specific entry in a DList. The interface doesn't seem to provide a way to get a pointer to a raw node struct, so about the best solution I can find is to get a range out of the list, pop elements until I get to the one I want to store, and save a reference to the front of the range with theRange.takeOne. I could then remove that node with theList.remove(theSavedNode), insert before/after it, etc., but I can't see a good way to just _get_ the node before or after it. Is there a good way to do this with the current interface, or would it need to be extended?
Re: C header file: tagged enumerations
On Tuesday, 26 April 2016 at 23:40:24 UTC, Adam D. Ruppe wrote: D doesn't handle this C pattern well... you basically have to rewrite the whole thing for each version. Or you can use the technique that's used in llvm-d: build the enumeration from a string mixin which is generated from a table. It's not necessarily the most elegant solution, but it can eliminate some code duplication.
Re: Functions that return type
On Wednesday, 20 January 2016 at 10:04:03 UTC, burjui wrote: That's alright. Parsing and AST construction are trivial with S-expressions (Lisp-like syntax), so if you use them for the early stages of development, you can focus on the type system. When you're done with types, you can switch to making a better grammar for your language. True. I'd been playing with the idea of having multiple syntactic "front-ends" anyway (mainly for the purpose of making DSLs), so it wouldn't be too much of a stretch to use an S-expression syntax. One problem, though, is that I'd either have to extend that syntax to support some of the constructs I want (i.e array literals) or create a bunch of variadic constructor functions (which could be evaluated at compile time). Of course, S-expression syntax is kind of designed to be extensible... That's all off-topic, though. ;)
Re: Functions that return type
On Sunday, 17 January 2016 at 02:08:06 UTC, Timon Gehr wrote: On 01/16/2016 11:50 PM, data pulverizer wrote: I guess the constraints are that of a static language. (This is not true.) I'm playing with the design of such a language myself. Basically, anything can create/use/return type objects, but a variable of a particular type can only be instantiated using an immutable type object whose value is known at compile time. It's not very far along, though. Right now, I have a "compiler" that parses integers and parentheses. ;)
Re: How do you create an opengl window with DerelictOrg?
On Monday, 7 December 2015 at 21:33:57 UTC, Enjoys Math wrote: I've seen these: https://github.com/DerelictOrg?page=1 BUt not sure how to use them, examples? OpenGL itself can't create a window/context, so you'll need to use DerelictGLFW or DerelictSDL. GLFW is lighter-weight. Combine the setup code from here: https://github.com/DerelictOrg/DerelictGLFW3 ...with the example code from here: http://www.glfw.org/documentation.html Don't forget to load DerelictGL when you load DerelictGLFW. In addition, after you have the OpenGL context, you'll need to call DerelictGL3.reload() if you want anything more advanced than OpenGL 1.1. https://github.com/DerelictOrg/DerelictGL3
Re: Password Storage
On Friday, 27 November 2015 at 16:14:06 UTC, H. S. Teoh wrote: True, so you'd store hash(password01) in the database, and compute hash(X + hash(password)) during authentication. T Another option is SCRAM: https://en.wikipedia.org/wiki/Salted_Challenge_Response_Authentication_Mechanism
Re: Password Storage
On Friday, 27 November 2015 at 02:05:49 UTC, H. S. Teoh wrote: For authentication, the password shouldn't even be sent over the wire. Instead, the server (which knows the correct password) should send a challenge to the client (i.e., a large random number produced by a good RNG -- which is different each time the user authenticates). The client should then prepend this challenge to the password typed in by the user, and compute the hash of the result. This hash is sent back to the server, which does the same computation on its own, and checks whether the two hash values match. Provided you're using a good cryptographic hash, the only way the client will be able to provide the right answer is if the user actually knows the password. At no time is the password ever sent over the network, encrypted or not. --T The issue I see with this is that the server has to _know_ the password in order to hash it with the challenge. If the server is compromised, guess who else knows the password now? Some kind of public-key encryption/signing might work, though.
Re: Something about Chinese Disorder Code
On Tuesday, 24 November 2015 at 09:48:45 UTC, magicdmer wrote: I display chinese string like: auto str = "你好，世界" writeln(str) and The display is garbled。 some windows api like MessageBoxA ,if string is chinese, it displays disorder code too i think i must use WideCharToMultiByte to convert it , is there any other answer to solve this question simplely You can also try using a wide string literal, i.e. "你好，世界"w. The suffix forces the string to use 16-bit characters. The garbled display from writeln might be related to your console settings. If you aren't using the UTF-8 codepage in cmd.exe, that would explain why the text appears garbled. Unfortunately, Windows has some significant bugs with UTF-8 in the console.
Finding packages recursively
I'm trying to recursively visit a package and all packages/modules within it using metaprogramming. I should be able to use __traits(allMembers, somePackage) recursively to get all symbols within the package, but is there an easy way to determine whether a symbol represents a package, a module, or something else?
