generic-programming

问题 spent some time again with the scripting interface of my app. i guess i now have an advanced dlr problem here. I have a python script I have an .NET object [o1] I call a method on the python script from .NET via Iron Python. The python code creates an object [o2] The python code calls an method on object [o1] passing [o2] as an argument (Via subclassing DynamicMetaObject) In the .NET code of the o1-method i want to dynamically call methods on o2 For example i could do that via ((dynamic)o2)

问题 I have the following struct: pub struct Foo<T> { some_value: T, } impl<T> Foo<T> { pub fn new(value: T) -> Self { Self { some_value: value } } } // Implement `Default()`, assuming that the underlying stored type // `T` also implements `Default`. impl<T> Default for Foo<T> where T: Default, { fn default() -> Self { Self::new(T::default()) } } I would like Foo::default() to be available if T implements Default , but not available otherwise. Is it possible to specify "conditional implementation"

问题 I have the following struct: pub struct Foo<T> { some_value: T, } impl<T> Foo<T> { pub fn new(value: T) -> Self { Self { some_value: value } } } // Implement `Default()`, assuming that the underlying stored type // `T` also implements `Default`. impl<T> Default for Foo<T> where T: Default, { fn default() -> Self { Self::new(T::default()) } } I would like Foo::default() to be available if T implements Default , but not available otherwise. Is it possible to specify "conditional implementation"

问题 How does one go about implementing a subtype of Numeric[T]? I have been looking for at guide on this but haven't found any. Example of subtypes could be Rational or Complex? Thanks in advance Troels 回答1: An absolutely useless String Numeric: trait StringIsNumeric extends Numeric[String] { def plus(x: String, y: String): String = "%s+%s" format (x, y) def minus(x: String, y: String): String = "%s-%s" format (x) def times(x: String, y: String): String = "%s*%s" format (x, y) def quot(x: String,

问题 How does one go about implementing a subtype of Numeric[T]? I have been looking for at guide on this but haven't found any. Example of subtypes could be Rational or Complex? Thanks in advance Troels 回答1: An absolutely useless String Numeric: trait StringIsNumeric extends Numeric[String] { def plus(x: String, y: String): String = "%s+%s" format (x, y) def minus(x: String, y: String): String = "%s-%s" format (x) def times(x: String, y: String): String = "%s*%s" format (x, y) def quot(x: String,

问题 I'm trying to use this https://stackoverflow.com/a/31641779/1586965 (How to use shapeless to convert generic Map[String, Any] to case class inside generic function?) to process case class Address(street: String, zip: Int) case class PersonOptionalAddress(name: String, address: Option[Address]) I have a test that fails: "Convert Map to PersonOptionalAddress Some" in { CaseClassFromMap[PersonOptionalAddress](Map( "name" -> "Tom", "address" -> Some(Map("street" -> "Jefferson st", "zip" -> 10000)

问题 What exactly is the difference? It seems like the terms can be used somewhat interchangeably, but reading the wikipedia entry for Objective-c, I came across: In addition to C’s style of procedural programming, C++ directly supports certain forms of object-oriented programming, generic programming, and metaprogramming. in reference to C++. So apparently they're different? 回答1: Programming : Writing a program that creates, transforms, filters, aggregates and otherwise manipulates data.

问题 What exactly is the difference? It seems like the terms can be used somewhat interchangeably, but reading the wikipedia entry for Objective-c, I came across: In addition to C’s style of procedural programming, C++ directly supports certain forms of object-oriented programming, generic programming, and metaprogramming. in reference to C++. So apparently they're different? 回答1: Programming : Writing a program that creates, transforms, filters, aggregates and otherwise manipulates data.

问题 I have data laid out in memory in a Structure of Arrays (SoA) or Sturcture of Pointers (SoP) form, and have a way to access that data as though it were laid out in Array of Structure (AoS) form -- code given below. However, I am not too happy about use of struct AoS_4_SoP -- although this struct appears to use templates, it is not really generic since, for example, foo and bar are hard-coded inside it. Two questions/requests: 1) For read-write performance, is AoS access provided as good as

问题 I'm currently trying to implement a generic method to adapt a DTO that comes from an external service into a model of my servisse and I ran into an issue. First let me just contextualize the problem. Let's say that an external service returns the following DTO to my application. public class ExampleDTO { public int Field1 { get; set; } public int Field2 { get; set; } } And this is my model. public class ExampleModel { public int Field1 { get; set; } public int Field2 { get; set; } } If I