D is a high-level, multi-paradigm programming language that combines efficient low-level programming capabilities with the convenience of high-level features, making it suitable for a wide range of applications. It was designed to provide a modern alternative to C and C++, offering powerful abstractions and features without sacrificing performance. D supports imperative, object-oriented, and functional programming styles, allowing developers to choose the approach that best suits their needs.
D was created by Walter Bright at his company, Digital Mars, in the late 1990s. The language was initially developed as an evolution of C and C++, aimed to provide improved productivity and performance. The first public release occurred in 2001, and as the language matured, it incorporated features and concepts from other languages, including Java, C#, and Python.
D draws inspiration from various programming languages, tailoring its features to create a versatile environment. It incorporates aspects from C and C++ for low-level memory management, and from Java and C# for garbage collection and object-oriented programming. D is also related to languages like Go and Rust, which focus on performance and safety.
As of October 2023, D continues to evolve, maintained by the D Language Foundation and an active community. Collaborative development has led to feature enhancements and improved interoperability with other languages. D is increasingly being adopted for system software, game development, and applications requiring high performance.
D features strong static typing, allowing developers to catch errors at compile time. For example:
int x = 10;
string y = "Hello, World!";
D includes a garbage collector, freeing developers from manual memory management tasks. This can be demonstrated as follows:
void main() {
auto str = new string("Welcome to D");
writeln(str);
}
D supports powerful template metaprogramming capabilities, allowing for generic programming. Here’s an example of a simple template:
T max(T)(T a, T b) {
return a > b ? a : b;
}
A unique feature of D is mixins, allowing code to be injected at compile time:
mixin template AddFunction {
int add(int a, int b) {
return a + b;
}
}
class MyClass {
mixin AddFunction;
}
D treats functions as first-class citizens, making it easy to pass functions around:
void main() {
auto add = (int a, int b) { return a + b; };
writeln(add(5, 3));
}
D provides built-in support for multi-threading, making concurrent programming simpler:
import core.thread;
void run() {
// Thread work
}
void main() {
auto t = new Thread(&run);
t.start();
t.join();
}
D provides native support for nullable types, improving safety when dealing with uninitialized variables:
void main() {
int? maybeInt = null;
if (maybeInt !is null) {
writeln(maybeInt);
}
}
D offers synchronized functions to easily manage thread safety:
synchronized void safeFunction() {
// Thread-safe code here
}
D has a flexible attribute system for adding metadata to functions, classes, and variables:
@safe void main() {
// Safe code
}
D includes built-in support for unit testing, allowing for easy testing of code:
import std.stdio;
import std unittest;
void test_example() {
assert(1 + 1 == 2);
}
unittest {
test_example();
}
D has several compilers, with the most notable being the DMD (D Digital Mars Compiler), LDC (LLVM D Compiler), and GDC (GNU D Compiler). These compilers support different backends and optimizations, providing flexibility based on project needs.
Popular IDEs for D include Visual Studio Code with the D extension, Code::Blocks, and Eclipse with DDT (D Development Tools). These IDEs provide syntax highlighting, code completion, debugging tools, and integrated build system support.
To build a D project, developers typically utilize the dub build tool, which handles dependency management and project configuration. A basic build can be executed with the command:
dub build
This command compiles the project based on settings defined in the dub.json or dub.sdl file.
D is used in various domains, including:
The ability to produce high-performance, reliable software makes it a suitable choice for performance-critical applications.
D's design shares similarities and contrasts with several programming languages:
D provides similar low-level capabilities as C and C++, but with features such as automatic memory management and a more modern syntax. Unlike C++, D has a focus on simplicity and ease of use.
While D supports garbage collection like Java and C#, it additionally allows for manual memory management for performance-critical applications. D also supports templates, a feature more akin to C++ compared to the generics found in Java and C#.
Python excels in ease of use and rapid development; however, D's performance shines in scenarios requiring high speed and low-level access. D's features, such as first-class functions and mixins, provide a level of expressiveness close to Python while maintaining performance.
Go emphasizes simplicity and concurrency at the cost of some low-level control. Rust focuses on memory safety and concurrency but has a steeper learning curve. D occupies a middle ground, offering both performance and safe concurrency features.
Ruby and PHP are designed for ease of use in web development, while D targets performance and system-level programming. D can be used for backend services where speed is essential.
D can serve as a target for source-to-source compilation due to its close representation of C. Utilizing tools like d2c, developers can convert D code to C for interoperability with C libraries, making it easier to integrate D into existing C projects.