Re: Why does nobody seem to think that `null` is a serious problem in D?
On Monday, 19 November 2018 at 21:23:31 UTC, Jordi Gutiérrez Hermoso wrote: When I was first playing with D, I managed to create a segfault by doing `SomeClass c;` and then trying do something with the object I thought I had default-created, by analogy with C++ syntax. Seasoned D programmers will recognise that I did nothing of the sort and instead created c is null and my program ended up dereferencing a null pointer. I'm not the only one who has done this. I can't find it right now, but I've seen at least one person open a bug report because they misunderstood this as a bug in dmd. I have been told a couple of times that this isn't something that needs to be patched in the language, but I don't understand. It seems like a very easy way to generate a segfault (and not a NullPointerException or whatever). What's the reasoning for allowing this? This is because you're transfering what you know from C++ to D, directly. You shouldn't do that, check out how the specific feature works in the particular language. I used C# mostly and Foo f; wouldn't make sense for me, it's not allocated, ti's null. So right away I used Foo f = new Foo();
What can I use to parse a date string in a custom format?
I've been looking for a function or library to parse a date in a custom format (for validation) similar to C#'s [1] TryParseExactbut I couldn't find any. so far I only found fromISOExtString(), and fromSimpleString() which doesn't allow me to set a custom string format. I've looked up at https://code.dlang.org/search?q=date https://code.dlang.org/search?q=date+parsing but to my surpise I didn't find either. Am I using wrong keywords or there's no really such method implemented yet? [1]: https://docs.microsoft.com/en-us/dotnet/api/system.datetime.tryparseexact?redirectedfrom=MSDN&view=netframework-4.7.2#System_DateTime_TryParseExact_System_String_System_String_System_IFormatProvider_System_Globalization_DateTimeStyles_System_DateTime__
How do I the temlate parameter name as string?
ParameterIdentifierTuple from std.traits did work fine for
regular functions but not for template functions:
Error: template instance
`std.traits.ParameterIdentifierTuple!(f)` does not match
template declaration `ParameterIdentifierTuple(func...) if
(func.length == 1 && isCallable!func)` (foo)
f is defined as:
void f(T)(T t, string p)
if(is(T == A) || is(T == B))
{
// ...
}
my goal is get "p" as string.
