Wednesday 23 March 2011

D Programming Language

"It seems to me that most of the "new" programming languages fall into one of two categories: Those from academia with radical new paradigms and those from large corporations with a focus on RAD and the web. Maybe it's time for a new language born out of practical experience implementing compilers." -- Michael
"Great, just what I need.. another D in programming." -- Segfault
D is a systems programming language. Its focus is on combining the power and high performance of C and C++ with the programmer productivity of modern languages like Ruby and Python. Special attention is given to the needs of quality assurance, documentation, management, portability and reliability.
The D language is statically typed and compiles directly to machine code. It's multiparadigm, supporting many programming styles: imperative, object oriented, and metaprogramming. It's a member of the C syntax family, and its appearance is very similar to that of C++. Here's a quick list of features.
It is not governed by a corporate agenda or any overarching theory of programming. The needs and contributions of the D programming community form the direction it goes.
There are two versions of the language:
  1. D version 1 which is in maintenance mode.
  2. D version 2 which is recommended for new projects.

There are currently four implementations:
  1. Digital Mars dmd for Windows 1.0 2.0, x86 Linux 1.0 2.0, Mac OS X 1.0 2.0, and x86 FreeBSD 1.0
  2. LLVM D Compiler ldc for D version 1.
  3. Gnu D compiler gdc.
  4. D.NET compiler alpha for .NET for D version 2.

A large and growing collection of D source code and projects are at dsource. More links to innumerable D wikis, libraries, tools, media articles, etc. are at dlinks.
This document is available as a pdf, as well as in Japanese and Portugese translations. A German book Programming in D: Introduction to the new Programming Language is available, as well as a Japanese book D Language Perfect Guide, and a Turkish book D Programlama Dili Dersleri.
This is an example D program illustrating some of the capabilities:
#!/usr/bin/dmd -run/* sh style script syntax is supported */

/* Hello World in D
   To compile:
     dmd hello.d
   or to optimize:
     dmd -O -inline -release hello.d
*/

import std.stdio;
void main(string[] args)
{
    writeln("Hello World, Reloaded");

    // auto type inference and built-in foreach    foreach (argc, argv; args)
    {
        // Object Oriented Programming        auto cl = new CmdLin(argc, argv);
        // Improved typesafe printf        writeln(cl.argnum, cl.suffix, " arg: ", cl.argv);
        // Automatic or explicit memory management        delete cl;
    }

    // Nested structs and classes    struct specs
    {
        // all members automatically initialized        int count, allocated;
    }

    // Nested functions can refer to outer    // variables like args    specs argspecs()
    {
        specs* s = new specs;
        // no need for '->'        s.count = args.length;     // get length of array with .length        s.allocated = typeof(args).sizeof; // built-in native type properties        foreach (argv; args)
            s.allocated += argv.length * typeof(argv[0]).sizeof;
        return *s;
    }

    // built-in string and common string operations    writefln("argc = %d, " ~ "allocated = %d",
 argspecs().count, argspecs().allocated);
}
class CmdLin
{
    private int _argc;
    private string _argv;
public:
    this(int argc, string argv) // constructor    {
        _argc = argc;
        _argv = argv;
    }

    int argnum()
    {
        return _argc + 1;
    }

    string argv()
    {
        return _argv;
    }

    string suffix()
    {
        string suffix = "th";
        switch (_argc)
        {
          case 0:
            suffix = "st";
            break;
          case 1:
            suffix = "nd";
            break;
          case 2:
            suffix = "rd";
            break;
          default:
     break;
        }
        return suffix;
    }
}

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