interface

问题 package main type Writeable interface { OnWrite() interface{} } type Result struct { Message string } func (r *Result) OnWrite() interface{} { return r.Message } // what does this line mean? what is the purpose? var _ Writeable = (*Result)(nil) func main() { } The comments in the code snippet expressed my confusion. As I understood, the line with comment notifies the compiler to check whether a struct has implemented the interface, but I am not sure very much. Could someone help explaining

问题 I'm trying to get the maximum from my list of countries (as in, maximum of it) is it possible to try something with a for each loop in the list of objects? I really want to do it in the maximum method. I know the method is wrong, but I'm trying some stuff out to get the maximum out of it Here's my code class Main { public static void main(String args[]) { Measurable[] countries = new Measurable[3]; countries[0] = new Country("Uruguay", 176220); countries[1] = new Country("Thailand", 514000);

问题 I need help with making this work for any type. I have got a function I need to accept other types that have ID property. I have tried using interfaces but that did not work for my ID property case. Here is the code: package main import ( "fmt" "strconv" ) type Mammal struct{ ID int Name string } type Human struct { ID int Name string HairColor string } func Count(ms []Mammal) *[]string { // How can i get this function to accept any type not just []Mammal IDs := make([]string, len(ms)) for i,

问题 I need help with making this work for any type. I have got a function I need to accept other types that have ID property. I have tried using interfaces but that did not work for my ID property case. Here is the code: package main import ( "fmt" "strconv" ) type Mammal struct{ ID int Name string } type Human struct { ID int Name string HairColor string } func Count(ms []Mammal) *[]string { // How can i get this function to accept any type not just []Mammal IDs := make([]string, len(ms)) for i,

问题 I would like an object to be comparable (to use it in a TreeSet in that case). My object got a name field and I would like it to be sorted by alphabetical order. I thought first that I could use the unicode value of the string and simply do a subtraction, but then AA would be after Ab for example… Here’s how I started : public final class MyObject implements Comparable<MyObject> { private String name; public MyObject(String name) { this.name = name; } public String name() { return name; }

问题 I would like an object to be comparable (to use it in a TreeSet in that case). My object got a name field and I would like it to be sorted by alphabetical order. I thought first that I could use the unicode value of the string and simply do a subtraction, but then AA would be after Ab for example… Here’s how I started : public final class MyObject implements Comparable<MyObject> { private String name; public MyObject(String name) { this.name = name; } public String name() { return name; }

问题 I have the following interfaces: export interface Meta { counter: number; limit: number; offset: number; total: number; } export interface Api<T> { [key: string]: T[]; meta: Meta; // error } Currently, I'm receiving the following error: Property 'meta' of type 'Meta' is not assignable to string index type 'T[]'. After searching a bit, I found this statement in TS docs: While string index signatures are a powerful way to describe the “dictionary” pattern, they also enforce that all properties

问题 I recently came across (again) the Delphi compiler code-gen bug when passing an interface as const leaks a reference. This happens if your method is declared to pass an interface variable as const , e.g.: procedure Frob(const Grob: IGrobber); and the fix is to simply remove the const : procedure Frob(Grob: IGrobber); I understand that const (and var , and out ) allow you to pass items by reference . In the case of a structure this saves an argument copy; letting you instead simply pass the

问题 I recently came across (again) the Delphi compiler code-gen bug when passing an interface as const leaks a reference. This happens if your method is declared to pass an interface variable as const , e.g.: procedure Frob(const Grob: IGrobber); and the fix is to simply remove the const : procedure Frob(Grob: IGrobber); I understand that const (and var , and out ) allow you to pass items by reference . In the case of a structure this saves an argument copy; letting you instead simply pass the