Язык программирования D (Николай Толстокулаков)

Николай Толстокулаков (Ixtens) рассказывает об истории, синтаксисе и фичах языка D.

http://techtalks.nsu.ru

Transcript

1. Dlang Tolstokulakov Nikolay
2. Going to native 1. C++11 2. GoLang 3. Rust 4. DLang
3. Authors Andrei Alexandrescu • Modern C++ Design: Generic Programming and Design Patterns Applied • C++ Coding Standards: 101 Rules, Guidelines, and Best Practices. • The D Programming Language. Walter Bright • C and C++ compilers: ◦ Digital Mars C++ ◦ Symantec C++ ◦ Zortech C++ (the first native C++ compiler)
4. Dlang.org D is a language with C-like syntax and static typing. It pragmatically combines efficiency, control, and modeling power, with safety and programmer productivity. • Convenience - minimal boilerplate, automatic memory management, slices, ranges • Power - polymorphism, value semantics, functional style, generics, generative programming, contract programming, ... Innovative approach to concurrency • Efficiency - native code, native pointers, type casts, access to any C function, and even inline assembly code
5. TIOBE Programming Community Index for October 2013 21 R 0.553% 31 ABAP 0.394% 41 JavaFX Script 0.297% 22 SAS 0.543% 32 C shell 0.382% 42 Tcl 0.294% 23 Ada 0.510% 33 Common Lisp 0.380% 43 Erlang 0.292% 24 F# 0.499% 34 NXT-G 0.366% 44 Max/MSP 0.276% 25 Fortran 0.474% 35 Scheme 0.360% 45 Scratch 0.270% 26 Assembly 0.471% 36 Scala0.345% 46 Haskell 0.245% 27 Bash 0.470% 37 D 0.337% 47 ML 0.245% 28 Ladder Logic 0.457% 38 Prolog 0.328% 48 PL/I 0.240% 29 Logo 0.433% 39 RPG (OS/400) 0.319% 49 ActionScript 0.215% 30 Lua 0.413% 40 PostScript 0.312% 50 Emacs Lisp 0.210%
6. DLang • It is complex (more 100 keywords vs 50 in Java) • Syntactic sugar & features ◦ slices, auto, powerful foreach, final switch, ... ◦ unit tests, contract programming ◦ compile time intersection ◦ lamda, delegate ◦ scope ◦ ranges ◦ anti-hijacking ◦ ……… • Powerful metaprogramming
7. The sope statement (Java, C#) (action) try{ (next) }catch(Exception e){ (rollback) throw e }finally{ (cleanup) }
8. The scope statement (actionN) scope(failure) (rollbackN) scope(exit) (cleanupN) (actionN+1) scope(failure) (rollbackN+1) scope(exit) (cleanupN+1)
9. Built-in array bool binarySearch(T)(T[] input, T value) { if (input.empty) return false; auto i = input.length / 2; auto mid = input[i]; if (mid > value) return binarySearch(input[0 .. i]); if (mid < value) return binarySearch(input[i + 1 .. $]); return true; }
10. Ranges InputRange: • front - get the first element of the range • popFront - remove the first element of the range • empty - are there more elements in the range? InputRange ↑ ForwardRange ↗ ↖ BidirectionalRange RandomAccessRange (infinite) ↑ RandomAccessRange (finite)
11. Ranges - sort input stream #1 import std.array, std.algorithm, std.stdio; void main(){ auto lines = stdin.byLine(KeepTerminator.yes); auto dupLines = map!(a => a.idup)(lines); auto arrLines = array(dupLines); sort(arrLines); copy(arrLines, stdout.lockingTextWriter()); }
12. Sort input stream #2 (UFCS) #!/usr/bin/rdmd import std.array, std.algorithm, std.stdio; void main(){ stdin.byLine(KeepTerminator.yes) .map!(a => a.idup) .array .sort .copy(stdout.lockingTextWriter()); }
13. Voldemort типы http://habrahabr.ru/post/183488/ auto generator(uint seed) { struct RandomNumberGenerator { @property int front() { return ((seed / 0x10000) * seed) >> 16; } void popFront() { seed = seed * 1103515245 + 12345; } @property bool empty() { return false; } } RandomNumberGenerator g; g.popFront(); // get it going return g; }
14. Compile time functions - C++ template <int N> struct Factorial { enum { value = N * Factorial<N - 1>::value }; }; template <> struct Factorial<0> { enum { value = 1 }; }; void foo() { int x = Factorial<0>::value; // == 1 int y = Factorial<4>::value; // == 24 }
15. Compile time - DLang import std.stdio, std.bigint; BigInt factorial(uint n){ BigInt rs = 1; foreach(i; 1..n+1) rs *= i; return rs; } enum f3 = factorial(20); void main(){ writefln("%s - %s", f3, factorial(4)); }
16. Pegged https://github.com/PhilippeSigaud/Pegged/ mixin(grammar(` Arithmetic: Term < Factor (Add / Sub)* Add < "+" Factor Sub < "-" Factor Factor < Primary (Mul / Div)* Mul < "*" Primary Div < "/" Primary …………….. `));
17. float interpreter(string expr){ auto p = Arithmetic(expr); float value(ParseTree p) { switch (p.name) { case "Arithmetic": return value(p.children[0]); case "Arithmetic.Term": …………………………. void main(string args[]){ pragma(msg, interpreter("1 + 2 - (3-5)*6")); foreach(a; args[1 .. $]) writefln("%s = %s", a, interpreter(a)); }
18. Dynamic typing http://wiki.dlang.org/Dynamic_typing var fromArgs = var.fromJson(args[1]); writefln("%s", fromArgs.keys); uint ids[] = cast(uint[])fromArgs.keys; var newIds = ids.map!(a=>a*2).array; fromArgs.keys = newIds; writefln("%s", fromArgs); string strIds[] = cast(string[])fromArgs.keys; var newStrIds = strIds.map!(a=>a~"!").array; fromArgs.keys = newStrIds; writefln("%s", fromArgs); ./jsvar_test '{"keys":[1,2,3]}' [1, 2, 3] {"keys":[2,4,6]} {"keys":["2!","4!","6!"]}
19. Compilers, IDE, tools, … http://wiki.dlang.org/The_D_Programming_Language • Compilers: dmd, gdc, ldc • IDE ◦ DDT - Eclipse based ◦ Mono-D ◦ Visual-D
20. Materials • dlang.org • dconf.org • The D Programming Language (Andrei Alexandrescu) • Three Unlikely Successful Features of D