# mission by Seppo Silaste
# http://blender.stackexchange.com/questions/13484/using-python-to-create-a-curve-and-attach-its-endpoints-with-hooks-to-two-sphere
import bpy


def hookCurve(o1, o2, scn):
    curve = bpy.data.curves.new("link", 'CURVE')

    curve.bevel_depth = 0.2
    curve.bevel_resolution = 4

    spline = curve.splines.new('BEZIER')

    spline.bezier_points.add(1)
    p0 = spline.bezier_points[0]
    p1 = spline.bezier_points[1]
    p0.co = o1.location
    p0.handle_right_type = 'VECTOR'
    p1.co = o2.location
    p1.handle_left_type = 'VECTOR'
    
    obj = bpy.data.objects.new("link", curve)
    
    m0 = obj.modifiers.new("alpha", 'HOOK')
    m0.object = o1
    m1 = obj.modifiers.new("beta", 'HOOK')
    m1.object = o2
    
    scn.objects.link(obj)
    scn.objects.active = obj
    
    # using anything in bpy.ops is a giant pain in the butt
    bpy.ops.object.mode_set(mode='EDIT')
    
    p0 = curve.splines[0].bezier_points[0]
    p1 = curve.splines[0].bezier_points[1]
    
    # Because the API on the hook modifier is incomplete, 
    # we must resort to using bpy.ops.
    p0.select_control_point=True
    bpy.ops.object.hook_assign(modifier="alpha")
    
    p0.select_control_point = False
    p1.select_control_point = True
    bpy.ops.object.hook_assign(modifier="beta")
    
    bpy.ops.object.mode_set(mode='OBJECT')

    return obj

o1 = bpy.data.objects['atom 1']
o2 = bpy.data.objects['atom 2']

obj = hookCurve(o1,o2, bpy.context.scene)

bpy.context.scene.objects.active = obj