Problem instantiating a LineAgent object in Python mode

[co-ord]

Dear @sghr,

Folks on the Processing forum (me included) have a hard time figuring out how to port your sketch on Particle-based Branching with Spring Force to Python.

It seems you are putting an instruction as an argument inside of super() when initializating the LineAgent constructor:

super(parent.pos().cp(dir)) on line 7 of the snippet below

class LineAgent extends IParticle{ 
  LineAgent parent;
  boolean isColliding;
  IVec dir;
    
  LineAgent(IParticle parent, IVec dir){
    super(parent.pos().cp(dir));  // <-- here !
    if(parent instanceof LineAgent){
      this.parent = (LineAgent)parent;
    }
    isColliding=false;
    hide(); // hide point
    this.dir = dir;
    fric(0.2);
  }

How would that translate in Python mode ?

--Failed attempt--

class LineAgent(IParticle):
    def __init__(self, parent, dir):
        super(LineAgent, self).__init__(parent, dir) #or IParticle.__init__(self, parent, dir)
        
        #parent.pos().cp(dir) #<-- WHERE should this go ?
        
        if isinstance(parent, LineAgent):
            self.parent = parent
        
        self.isColliding = False
        self.dir = dir
        self.hide()
        self.fric(0.2)

No matter what we try, we always end-up with an annoying 'instancemethod' object has no attribute 'pos' error.

-- Full sketch --

add_library('igeo')

def setup():
    size(480, 360, IG.GL)
    IG.bg(1.0)
    IG.top()

    for i in xrange(4):
        LineAgent(IParticle(IRand.pt(-40,-40,0,40,40,0)).hide().fric(0.2), IRand.dir(IG.zaxis).len(2))
    
    for i in xrange(20):
        IAttractor(IRand.pt(-200,-200,0,200,200,0)).linear(50).intensity(-30)

        
        
class LineAgent(IParticle):
    def __init__(self, parent, dir):
        super(LineAgent, self).__init__(parent, dir) 
        
        #parent.pos = parent.pos().cp(dir) #<-- WHERE should this go ?
        
        if isinstance(parent, LineAgent):
            self.parent = parent

        self.isColliding = False
        self.dir = dir
        self.hide()
        self.fric(0.2)

    
    def interact(self, agents):
        if self.time() == 0:
            for agent in agents:
                if isinstance(agent, LineAgent) and agent != self:
                        
                    # ERROR below --> attributeError: 'instancemethod' object has no attribute 'pos'
                    # more specifically: 'self.parent' has no attribute 'pos'
                    
                    if agent.parent != None and agent.pos().dist(self.pos()) < self.pos().dist(self.parent.pos())*2:
                        intxn = IVec.intersectSegment(agent.parent.pos(), agent.pos(), self.parent.pos(), self.pos())
                        if intxn != None and not intxn.eq(self.parent.pos()) and not agent.isColliding:
                            self.isColliding = True
                            return
 
                            
    def update(self):
        if self.isColliding:
            self.del()
        else:
            if self.time() == 0 and self.alive():
                if self.parent != None and self.parent.alive():
                    ln = ISpringLine(self, self.parent, 100)
                    t = -cos(IG.time()*.015) * .5 + .5
                    ln.hsb(.7 - t*.2, 1, .8 - t*.2, .5)
                    if self.parent.parent != None and self.parent.parent.alive():
                        st = IStraightenerCurve(self, self.parent, self.parent.parent).tension(100)
                        st.hsb(.7 - t*.2, 1, .8 - t*.2, .5)
            
            if self.time() == 4:
                dir2 = self.dir.cp()
                angle = PI*.12
                if IRand.pct(50):
                    self.dir.rot(angle)
                    dir2.rot(-angle)
                else:
                    self.dir.rot(-angle)
                    dir2.rot(angle)
                    
                LineAgent(self, self.dir)
                if IRand.pct(20):
                    LineAgent(self, dir2)
                    
                l = LineAgent(self, dir2)