Python bindings - models

Consider the following reflected model defined in C++

// C++ code
namespace ns
{
    $model+ Point
    {
        int32 x;
        int32 y;
    };
}

The following Python code illustrates various ways of creating an instance of a Point object which is associated with a python object referenced by a python variable:

# python code

# Default constructed point, same as Point(0,0)
p = ns.Point()
print 'p = ' + `p`

# Members of model can be accessed using dot notation
p.x = 10
p.y = 20
print 'p = ' + `p`

# Constructor which initialises the members in the same order as they appear in the model
p = ns.Point(4,-5)
print 'p = ' + `p`

# Provide values of any subset of the members in any order using a comma separate list of name=value
# pairs, using the same of the member of the model.
p = ns.Point(X=3)       # Y will have default value of 0
p = ns.Point(Y=3,X=2)   # Order doesn't need to correspond to the order in which the members appear in the model
p = ns.Point(Y=1)       # X will have default value of 0

More complicated example

// C++ code

namespace dt
{
    $enum+ class TMonth
    {
        January,
        February,
        March,
        April,
        May,
        June,
        July,
        August,
        September,
        October,
        November,
        December
    };
    
    $model+ TDate
    {
        int32 Year;
        TMonth Month;
        int32 Day;
    };

    $model+ TTime
    {
        int32 Hour;
        int32 Minute;
        int32 Second;
    };

    $model+ TDateTime
    {
        TDate Date;
        TTime Time;
    };
}

namespace geom
{
    $enum+ class EColour
    {
        red,
        green,
        blue,
        magenta,
        cyan,
        yellow
    };

    $model+ TPoint
    {
        float32 X;
        float32 Y;
    };

    $model+ TLine
    {
        TPoint P1;
        TPoint P2;
    };

    $model+ TRect
    {
        TPoint P1;
        TPoint P2;
    };

    $model+ TCircle
    {
        TPoint C;
        float32 R; 
    };
    
    $model+ TPolygon
    {
        xvector<TPoint> V;
    };

    $variant+ TShape
    {
        default TCircle(TPoint(0,0),1);
        TPoint Point;
        TLine Line;
        TRect Rect; 
        TCircle Circle; 
        TPolygon Polygon;
    };
    
    $model+ TPicture <<multiline>>
    {
        string8 Name;
        string8 Author;
        dt::TDateTime CreationDate;
        EColour Colour;
        TRect BoundingBox;
        xvector<TShape> Shapes;
    };
}

The following Python code:

polygon = geom.TPolygon( [ geom.TPoint(X=1,Y=2), geom.TPoint(X=7,Y=-2) ] )
polygon.V.append( geom.TPoint(X=5,Y=1) )
polygon.V[0].X = 1000
polygon.V.append( polygon.V[1] )

picture = geom.TPicture(
        Name = "my picture",
        Author = "P. Hunt",
        Colour = geom.EColour.magenta,
        CreationDate = dt.TDateTime( Date = dt.TDate(2006,dt.TMonth.Jun,23) ),
        BoundingBox = geom.TRect( geom.TPoint(0,0), geom.TPoint(800,600) ),
        Shapes =
        [
            geom.TShape(),
            geom.TShape.Polygon(polygon),
            geom.TShape.Rect(),
            geom.TShape.Rect( geom.TPoint(X=5,Y=8), geom.TPoint(15,12) ),
            geom.TShape.Rect( geom.TPoint(Y=5,X=8), geom.TPoint(10,17) ),
            geom.TShape.Circle( geom.TPoint(), 5 ),
            geom.TShape.Circle( R=2 ),
            geom.TShape.Circle( C=geom.TPoint(X=100) )
        ]
    )
print('picture = {}'.format(picture))

produces the following output:

picture = TPicture
{
    Name = my picture
    Author = P. Hunt
    CreationDate = Jun 23 2006 00:00
    Colour = magenta
    BoundingBox = TRect(TPoint(0,0),TPoint(800,600))
    Shapes = [
        Circle(TCircle(TPoint(0,0),1)),
        Polygon(TPolygon([TPoint(1000,2),TPoint(7,-2),TPoint(5,1),TPoint(7,-2)])),
        Rect(TRect(TPoint(0,0),TPoint(0,0))),
        Rect(TRect(TPoint(5,8),TPoint(15,12))),
        Rect(TRect(TPoint(8,5),TPoint(10,17))),
        Circle(TCircle(TPoint(0,0),5)),
        Circle(TCircle(TPoint(0,0),2)),
        Circle(TCircle(TPoint(100,0),0))]
}