Namespaces - language feature

Example from C++, Real-Time Concurrent C:

#include <iostream>
using namespace std;

// Variable created inside namespace
namespace first
{
  int val = 500;
}
 
// Global variable
int val = 100;
// Ways to do it: https://en.cppreference.com/w/cpp/language/namespace
namespace ns_name { declarations }
inline namespace ns_name { declarations }
namespace { declarations }
ns_name::name
using namespace ns_name;
using ns_name::name;
namespace name = qualified-namespace ;
namespace ns_name::inline(since C++20)(optional) name { declarations }

Example from C#:

namespace MyNamespace;
class MyClass
{
  public void MyMethod()
  {
    System.Console.WriteLine("Creating my namespace");
  }
}

Example from TypeScript, Static Typescript:

// Typescript even supports splitting namespaces across multiple files:
// Validation.ts
namespace Validation {
    export interface StringValidator {
        isAcceptable(s: string): boolean;
    }
}
// LettersOnlyValidator.ts
/// <reference path="Validation.ts" />
namespace Validation {
    const lettersRegexp = /^[A-Za-z]+$/;
    export class LettersOnlyValidator implements StringValidator {
        isAcceptable(s: string) {
            return lettersRegexp.test(s);
        }
    }
}

Example from F#:

namespace Widgets
type MyWidget1 =
   member this.WidgetName = "Widget1"
module WidgetsModule =
   let widgetName = "Widget2"

Example from C3:

import std::io;
...
io::printf("%d", i);

Example from Slope:

(ns-create 'hello-world)
(ns-define
  'hello-world
  'print
  (lambda ()
    (display "hello world!\n")))
(hello-world::print)

Languages with Namespaces include C++, C#, TypeScript, F#, C3, Slope, Dale, Real-Time Concurrent C, Static Typescript

Languages without Namespaces include C, Objective-C, Speedie, Tick C

This question asks: Does the language have a namespace construct?

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