Dao Language for Scripting and Computing

Dao Programming Language

Dao is a simple yet powerful object-oriented programming language featured by, soft (or optional) typing, BNF-like macro system, regular expression, multi-dimensional numeric array, asynchronous function call for concurrent programming etc. Supporting for multi-threaded programming is also implemented as an integrate part of Dao. Network programming and concurrent programming by message passing interface are supported as standard library of Dao. Moreover, Dao can be easily extended with C/C++, through a simple and transparent interface; and easily embedded into other C/C++ programs as well.

Now the extending modules for Dao are gradually enriching, with modules for: CGI web programming, MYSQL database handling, Lapack and GSL numeric computing, GraphicsMagick image processing, MathGL mathematics plotting, OpenGL 3D graphics, SDL multimedia, VTK 3D model and data visualization, XML docuemt handling and Zlib data compression etc. It worths mentioning that, most of these modules that wrap a C/C++ library are wrapped by an automated tool that generates the wrapping codes directly from the header files of those library, and this automated tool is written in Dao. Moreover, Dao has also included a module with functionality similar to the Ctypes module for Python. This module is based on the FFI library, and allows directly calling C functions of a C library from Dao without wrapping the library.

List of features:

Support by	Feature summary
Language	Object-oriented programming
Language	Optional/soft typing system
Language	BNF-like macro, meta-programming
Language	Functional programming
Language	Arbitrary precision integer (big integer)
Language	Tuple type
Language	Numeric array type
Built-in Methods	String regular expression pattern matching
Built-in Libraries	Multi-threaded programming
Built-in Libraries	Network programming
Virtual Machine	Automatic memory management
Programming Interfaces	Embedding and extending
Programming Interfaces	Packing script files into executable
Extending Modules	Graphical User Interface (GUI) programming
Extending Modules	3D graphics
Extending Modules	Image processing
Extending Modules	CGI web programming
Extending Modules	Database handling
Extending Modules	Data compression
Extending Modules	XML document handling
Extending Modules	Numeric computation
Extending Modules	Running time C library binding
Script Tools	Automatic wrapping of C/C++ libraries

Here are little pieces of codes just to show how Dao look like:

# explicitly typing:
# declare variable with type:
var1 : double = 0.0;
var2 : map<string,float>;

# implicitly typing:
# define variables by enumerations:
list1 = { 1, 2, 3 }
map1 = { "CD"=>123, "AB"=>456 }
tuple1 = ( 123, "ABC" )
# tuple with named items
tuple2 = ( index => 123, name => "ABC" )
vector = [ 1, 2, 3 ]
matrix = [ 1, 2; 3, 4 ]

tuple2.name = "another name";
stdio.println( matrix[1,:] ); # second row

# function with parameter annotation:
routine Bar( a, b : int, c = "DEFAULT" )
{
   stdio.println( "parameters:", a, b, c )
}

class Point
{
  var X, Y, Z = 0.0;

  routine Point( x=0.0, y=0.0, z=0.0 ){
   X = x; Y = y; Z = z;
  }
}
# different ways of constructing class instances:
p1 = Point( 1, 2, 3 ); # calling constructor
p2 = Point{ 1, 2, 3 }; # enumerating fields
p3 = Point{ Z=>1, X=>2, Y=>3 }; # enumerating fields by names

# generators and coroutines with typed interfaces:
# int => tuple<int,int>
routine gen1( a = 0 )
{
  k = 0;
   while( k ++ < 3 ) a = yield( k, a );
    return 0,0;
}
routine gen2( a = 0 )
{
  return gen1( a );
}
g = @gen2( 1 );
stdio.println( 'main1: ', g( 1 ) );
stdio.println( 'main2: ', g( 100 ) );
stdio.println( 'main3: ', g( 200 ) );

# functional methods:
# method( parameter(s) )->|variable(s)|{ inlined_function }

a = { 1, 2, 3 }
b = map( a ) -> { 10*x } # produce { 10, 20, 30 }
b = map( a ) -> |x| { 10*x } # equivalent to above

# map() can take more than one lists as parameters:
b = { 11, 22, 33 }
c = map( a, b ) -> |x,y| { x + y }

# function composition
c = map( a, b )->|x,y|{ x + y, x - y }->|u,v| { u * v }

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created at 2009-02-19, 17:46 GMT
modified at 2009-09-22, 00:03 GMT