ported Scala classes

python/framework/framework.pyx

@@ -0,0 +1,138 @@
+##
+## GL convenience layer
+##
+from math import pi as PI
+
+from gl cimport *
+
+#from triangulator import Point
+
+include "triangulator.pyx"
+
+cdef extern from 'math.h':
+    double cos(double)
+    double sin(double)
+
+SEGMENTS = 25
+INCREMENT = 2.0 * PI / SEGMENTS
+    
+def init_gl(width, height):
+    #glEnable(GL_LINE_SMOOTH)
+    glEnable(GL_BLEND)
+    glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA)
+    glClearColor(0.0, 0.0, 0.0, 0.0)
+    glHint (GL_LINE_SMOOTH_HINT, GL_NICEST)
+    
+def reset_zoom(float zoom, center, size):
+
+    zinv = 1.0 / zoom
+    left = -size[0] * zinv
+    right = size[0] * zinv
+    bottom = -size[1] * zinv
+    top = size[1] * zinv
+    
+    # Reset viewport
+    glLoadIdentity()
+    glMatrixMode(GL_PROJECTION)
+    glLoadIdentity()
+    
+    # Reset ortho view
+    glOrtho(left, right, bottom, top, 1, -1)
+    glTranslatef(-center[0], -center[1], 0)
+    glMatrixMode(GL_MODELVIEW)
+    glDisable(GL_DEPTH_TEST)
+    glLoadIdentity()
+    
+    # Clear the screen
+    glClear(GL_COLOR_BUFFER_BIT)
+    
+def draw_polygon(verts, color):
+    r, g, b = color
+    glColor3f(r, g, b)
+    glBegin(GL_LINE_LOOP)
+    for v in verts:
+        glVertex2f(v[0], v[1])
+    glEnd()
+       
+##
+## Game engine / main loop / UI
+##
+from glfw cimport *
+
+import sys
+
+cdef extern from 'math.h':
+    double cos(double)
+    double sin(double)
+    double sqrt(double)
+
+# Keyboard callback wrapper
+kbd_callback_method = None
+
+cdef extern void __stdcall kbd_callback(int id, int state):
+    kbd_callback_method(id, state)
+
+
+cdef class Game:
+
+    title = "Poly2Tri"
+    
+    def __init__(self, window_width, window_height):
+        
+        p1 = Point(12, 10)
+        p2 = Point(50, 47)
+        print p1.cross(p2)
+     
+        glfwInit()
+        
+        # 16 bit color, no depth, alpha or stencil buffers, windowed
+        if not glfwOpenWindow(window_width, window_height, 8, 8, 8, 8, 24, 0, GLFW_WINDOW):
+            glfwTerminate()
+            raise SystemError('Unable to create GLFW window')
+        
+        glfwEnable(GLFW_STICKY_KEYS)
+        glfwSwapInterval(1) #VSync on
+
+    def register_kbd_callback(self, f):
+        global kbd_callback_method
+        glfwSetKeyCallback(kbd_callback)
+        kbd_callback_method = f
+
+    def main_loop(self):
+        
+        frame_count = 1
+        start_time = glfwGetTime()
+
+        running = True
+        while running:
+            
+            current_time = glfwGetTime()
+            
+            #Calculate and display FPS (frames per second)
+            if (current_time - start_time) > 1 or frame_count == 0:
+                frame_rate = frame_count / (current_time - start_time)
+                t = self.title + " (%d FPS)" % frame_rate
+                glfwSetWindowTitle(t)
+                start_time = current_time
+                frame_count = 0
+                
+            frame_count = frame_count + 1
+
+            # Check if the ESC key was pressed or the window was closed
+            running = ((not glfwGetKey(GLFW_KEY_ESC))
+                       and glfwGetWindowParam(GLFW_OPENED))
+             
+            self.update()
+            self.render()
+        
+            glfwSwapBuffers()
+
+            
+        glfwTerminate()
+        
+    property window_title:
+        def __set__(self, title): self.title = title
+        
+    property time:
+        def __get__(self): return glfwGetTime()
+        def __set__(self, t): glfwSetTime(t)

python/framework/glfw.pxd

@@ -0,0 +1,70 @@
+# GLFW Declarations
+# Copyright 2009 Mason Green & Tom Novelli
+#
+# This file is part of OpenMelee.
+#
+# OpenMelee is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# any later version.
+#
+# OpenMelee is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with OpenMelee.  If not, see <http://www.gnu.org/licenses/>.
+
+cdef extern from "GL/glfw.h":
+
+    ctypedef enum:
+        GLFW_WINDOW
+        GLFW_FULLSCREEN
+        GLFW_STICKY_KEYS
+        GLFW_OPENED
+        GLFW_KEY_ESC 
+        GLFW_PRESS
+    
+    # Function pointer types
+    ctypedef void (__stdcall * GLFWwindowsizefun)(int, int)
+    ctypedef int  (__stdcall * GLFWwindowclosefun)()
+    ctypedef void (__stdcall * GLFWwindowrefreshfun)()
+    ctypedef void (__stdcall * GLFWmousebuttonfun)(int, int)
+    ctypedef void (__stdcall * GLFWmouseposfun)(int, int)
+    ctypedef void (__stdcall * GLFWmousewheelfun)(int)
+    ctypedef void (__stdcall * GLFWkeyfun)(int, int)
+    ctypedef void (__stdcall * GLFWcharfun)(int, int)
+    ctypedef void (__stdcall * GLFWthreadfun)()
+        
+    int glfwInit()
+    void glfwTerminate()
+    void glfwSetWindowTitle(char *title)
+    int glfwOpenWindow( int width, int height,
+            int redbits, int greenbits, int bluebits, int alphabits,
+            int depthbits, int stencilbits, int mode )
+    void glfwSwapInterval( int interval )
+    void glfwSwapBuffers()
+    void glfwEnable( int token )
+    int glfwGetWindowParam( int param )
+    int glfwGetKey( int key )
+    int glfwGetWindowParam( int param )
+    void glfwGetWindowSize( int *width, int *height )
+    double glfwGetTime()
+    void glfwSetTime(double time)
+    
+    # Input handling
+    void glfwPollEvents()
+    void glfwWaitEvents()
+    int glfwGetKey( int key )
+    int glfwGetMouseButton( int button )
+    void glfwGetMousePos( int *xpos, int *ypos )
+    void glfwSetMousePos( int xpos, int ypos )
+    int  glfwGetMouseWheel()
+    void glfwSetMouseWheel( int pos )
+    void glfwSetKeyCallback(GLFWkeyfun cbfun)
+    void glfwSetCharCallback( GLFWcharfun cbfun )
+    void glfwSetMouseButtonCallback( GLFWmousebuttonfun cbfun )
+    void glfwSetMousePosCallback( GLFWmouseposfun cbfun )
+    void glfwSetMouseWheelCallback( GLFWmousewheelfun cbfun )
+    

python/framework/triangulator.pyx

@@ -0,0 +1,496 @@
+#
+# Poly2Tri
+# Copyright (c) 2009, Mason Green
+# http://code.google.com/p/poly2tri/
+# 
+# All rights reserved.
+# 
+# Redistribution and use in source and binary forms, with or without modification,
+# are permitted provided that the following conditions are met:
+# 
+# Redistributions of source code must retain the above copyright notice,
+# self list of conditions and the following disclaimer.
+# Redistributions in binary form must reproduce the above copyright notice,
+# self list of conditions and the following disclaimer in the documentation
+# and/or other materials provided with the distribution.
+# Neither the name of Poly2Tri nor the names of its contributors may be
+# used to endorse or promote products derived from self software without specific
+# prior written permission.
+# 
+# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
+# CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
+# EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
+# PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
+# PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
+# LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
+# NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+# SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+# 
+from math import floor
+
+###
+### Based on Raimund Seidel'e paper "A simple and fast incremental randomized
+### algorithm for computing trapezoidal decompositions and for triangulating polygons"
+### (Ported from poly2tri)
+
+cdef extern from 'math.h':
+    double cos(double)
+    double sin(double)
+    double sqrt(double)
+
+cdef list merge_sort(list l):
+    cdef list lleft, lright
+    cdef int p1, p2, p
+    if len(l)>1 :
+        lleft = merge_sort(l[:len(l)/2])
+        lright = merge_sort(l[len(l)/2:])
+        #do merge here
+        p1,p2,p = 0,0,0
+        while p1<len(lleft) and p2<len(lright):
+            if lleft[p1][0] < lright[p2][0]:
+                l[p]=lleft[p1]
+                p+=1
+                p1+=1
+            else:
+                l[p]=lright[p2]
+                p+=1
+                p2+=1
+        if p1<len(lleft):l[p:]=lleft[p1:]
+        elif p2<len(lright):l[p:]=lright[p2:]
+        else : print "internal error"
+    return l
+  
+cdef class Point:
+  
+    cdef float x, y
+    
+    next = None
+    prev = None
+    edge = None
+    edges = []
+    
+    property x:
+        def __get__(self): return self.x
+    
+    property y:
+        def __get__(self): return self.y
+        
+    def __init__(self, float x, float y):
+        self.x = x
+        self.y = y
+
+    def __sub__(self, other):
+        if isinstance(other, Point):
+            return Point(self.x - other.x, self.y - other.y) 
+        else:
+            return Point(self.x - other, self.y - other)
+    
+    def __add__(self, other):
+        if isinstance(other, Point):
+            return Point(self.x + other.x, self.y + other.y) 
+        else:
+            return Point(self.x + other, self.y + other)
+    
+    def __mul__(self, float f):
+        return Point(self.x * f, self.y * f)
+    
+    def __div__(self, float a):
+        return Point(self.x / a, self.y / a)
+    
+    def cross(self, Point p):
+        return self.x * p.y - self.y * p.x
+    
+    def dot(self, Point p):
+        return self.x * p.x + self.y * p.y
+    
+    def length(self):
+        return sqrt(self.x * self.x + self.y * self.y)
+        
+    def normalize(self):
+        return self / self.length() 
+        
+    def less(self, Point p):
+        return self.x < p.x
+  
+    '''
+    # Sort along y axis
+    def greater(self, p):
+        if y < p.y: 
+          return True
+        elif y > p.y:
+          return False
+        else:
+          if x < p.x:
+            return True
+          else:
+            return False
+    '''
+    
+    def not_equal(self, p):
+        return not (p.x == self.x and p.y == self.y)
+        
+    def clone(self):
+        return Point(self.x, self.y)
+  
+cdef class Edge:
+
+    cdef Point p, q
+    cdef bool above, below
+    cdef float slope, b
+ 
+    mpoints = []
+    
+    def __init__(self, Point p, Point q):
+        self.p = p
+        self.q = q
+        self.slope = (q.y - p.y)/(q.x - p.x)
+        self.b = p.y - (p.x * self.slope)
+  
+    property p:
+        def __get__(self): return self.p
+        
+    property q:
+        def __get__(self): return self.q
+        
+    property above:
+        def __get__(self): return self.above
+        
+    property below:
+        def __get__(self): return self.below
+        
+    cdef bool is_above(self, Point point):
+        return (floor(point.y) < floor(self.slope * point.x + self.b))
+    cdef bool is_below(self, Point point):
+        return (floor(point.y) > floor(self.slope * point.x + self.b))
+
+    cdef float intersect(self, Point c, Point d):
+        cdef float a1, a2, a3, a4, t
+        cdef Point a, b
+        a = self.p
+        b = self.q
+        a1 = self.signed_area(a, b, d)
+        a2 = self.signed_area(a, b, c)
+        if  a1 != 0 and a2 != 0 and (a1 * a2) < 0:
+            a3 = self.signed_area(c, d, a)
+            a4 = a3 + a2 - a1
+            if a3 * a4 < 0:
+                t = a3 / (a3 - a4)
+                return a + ((b - a) * t)
+        return 0.0
+        
+    cdef float signed_area(self, Point a, Point b, Point c):
+        return (a.x - c.x) * (b.y - c.y) - (a.y - c.y) * (b.x - c.x)
+
+cdef Point line_intersect(Edge e, float x):
+    cdef float y =  e.slope * x + e.b
+    return Point(x, y)
+        
+cdef class Trapezoid:
+
+    cdef:
+        Point lpoint, rpoint
+        Edge top, bottom
+        Trapezoid upper_left, lower_left
+        Trapezoid upper_right, lower_right
+        bool inside
+        
+    sink = None
+    
+    def __init__(self, Point lpoint, Point rpoint, Edge top, Edge bottom):
+        self.lpoint = lpoint
+        self.rpoint = rpoint
+        self.top = top
+        self.bottom = bottom
+        self.upper_left = None
+        self.upper_right = None
+        self.lower_left = None
+        self.lower_right = None
+        self.inside = True
+    
+    property upper_left:
+        def __get__(self): return self.upper_left
+        def __set__(self, Trapezoid other): self.upper_left = other
+        
+    property upper_right:
+        def __get__(self): return self.upper_right
+        def __set__(self, Trapezoid other): self.upper_right = other
+
+    property lower_left:
+        def __get__(self): return self.lower_left
+        def __set__(self, Trapezoid other): self.lower_left = other
+        
+    property lower_right:
+        def __get__(self): return self.lower_right
+        def __set__(self, Trapezoid other): self.lower_right = other
+        
+    def update_left(self, Trapezoid ul, Trapezoid ll):
+        self.upper_left = ul
+        self.lower_left = ll
+        if ul != None: ul.upper_right = self
+        if ll != None: ll.lower_right = self  
+  
+    def update_right(self, Trapezoid ur, Trapezoid lr):
+        self.upper_right = ur
+        self.lower_right = lr
+        if ur != None: ur.upper_left = self
+        if lr != None: lr.lower_left = self   
+
+    def update_left_right(self, Trapezoid ul, Trapezoid ll, Trapezoid ur, Trapezoid lr):
+        self.upper_left = ul
+        self.lower_left = ll 
+        self.upper_right = ur 
+        self.lower_right = lr   
+        if ul != None: ul.upper_right = self
+        if ll != None: ll.lower_right = self
+        if ur != None: ur.upper_left = self
+        if lr != None: lr.lower_left = self  
+        
+    def trim_neighbors(self):
+        if self.inside:
+            self.inside = False
+            if self.upper_left != None: self.upper_left.trim_neighbors()
+            if self.lower_left != None: self.lower_left.trim_neighbors()
+            if self.upper_right != None: self.upper_right.trim_neighbors()
+            if self.lower_right != None: self.lower_right.trim_neighbors()
+  
+    def contains(self, Point point):
+        return (point.x > self.lpoint.x and point.x < self.rpoint.x and 
+                self.top.is_above(point) and self.bottom.is_below(point))
+  
+    def vertices(self):
+        cdef list verts = []
+        verts.append(line_intersect(self.top, self.lpoint.x))
+        verts.append(line_intersect(self.bottom, self.lpoint.x))
+        verts.append(line_intersect(self.bottom, self.rpoint.x))
+        verts.append(line_intersect(self.top, self.rpoint.x))
+        return verts
+  
+    def add_points(self):
+        if self.lpoint != self.bottom.p: 
+            self.bottom.mpoints.append(self.lpoint.clone)
+        if self.rpoint != self.bottom.q: 
+            self.bottom.mpoints.append(self.rpoint.clone)
+        if self.lpoint != self.top.p: 
+            self.top.mpoints.append(self.lpoint.clone)
+        if self.rpoint != self.top.q: 
+            self.top.mpoints.append(self.rpoint.clone)
+
+class TrapezoidalMap:
+
+    map = {}
+    margin = 50
+    bcross = None
+    tcross = None
+
+    def clear(self):
+        self.bcross = None
+        self.tcross = None
+
+    def case1(self, t, e):
+        trapezoids = [None, None, None, None]
+        trapezoids.append(Trapezoid(t.lpoint, e.p, t.top, t.bottom))
+        trapezoids.append(Trapezoid(e.p, e.q, t.top, e))
+        trapezoids.append(Trapezoid(e.p, e.q, e, t.bottom))
+        trapezoids.append(Trapezoid(e.q, t.rpoint, t.top, t.bottom))
+        trapezoids[0].update_left(t.upper_left, t.lower_left)
+        trapezoids[1].update_left_right(trapezoids[0], None, trapezoids[3], None)
+        trapezoids[2].update_left_right(None, trapezoids[0], None, trapezoids[3])
+        trapezoids[3].update_right(t.upper_right, t.lower_right)
+        return trapezoids
+
+    def case2(self, t, e):
+        rp = e.q if e.q.x == t.rpoint.x else t.rpoint
+        trapezoids = [None, None, None]
+        trapezoids.append(Trapezoid(t.lpoint, e.p, t.top, t.bottom))
+        trapezoids.append(Trapezoid(e.p, rp, t.top, e))
+        trapezoids.append(Trapezoid(e.p, rp, e, t.bottom))
+        trapezoids[0].update_left(t.upper_left, t.lower_left)
+        trapezoids[1].update_left_right(trapezoids[0], None, t.upper_right, None)
+        trapezoids[2].update_left_right(None, trapezoids[0], None, t.lower_right)
+        self.bcross = t.bottom
+        self.tcross = t.top
+        e.above = trapezoids[1]
+        e.below = trapezoids[2]
+        return trapezoids
+  
+    def case3(self, t, e):
+        lp = e.p if e.p.x == t.lpoint.x  else t.lpoint
+        rp = e.q if e.q.x == t.rpoint.x else t.rpoint
+        trapezoids = [None, None]
+        if self.tcross is t.top:
+            trapezoids[0] = t.upper_left
+            trapezoids[0].update_right(t.upper_right, None)
+            trapezoids[0].rpoint = rp
+        else:
+            trapezoids[0] = Trapezoid(lp, rp, t.top, e)
+            trapezoids[0].update_left_right(t.upper_left, e.above, t.upper_right, None)
+        if self.bcross is t.bottom:
+            trapezoids[1] = t.lower_left
+            trapezoids[1].update_right(None, t.lower_right)
+            trapezoids[1].rpoint = rp
+        else:
+            trapezoids[1] = Trapezoid(lp, rp, e, t.bottom)
+            trapezoids[1].update_left_right(e.below, t.lower_left, None, t.lower_right)
+        self.bcross = t.bottom
+        self.tcross = t.top
+        e.above = trapezoids[0]
+        e.below = trapezoids[1]
+        return trapezoids
+
+    def case4(self, t, e):
+        lp = e.p if e.p.x == t.lpoint.x else t.lpoint
+        trapezoids = [None, None, None]
+        if self.tcross is t.top:
+            trapezoids[0] = t.upper_left
+            trapezoids[0].rpoint = e.q
+        else:
+            trapezoids[0] = Trapezoid(lp, e.q, t.top, e)
+            trapezoids[0].update_left(t.upper_left, e.above)
+        if self.bcross is t.bottom:
+            trapezoids[1] = t.lower_left
+            trapezoids[1].rpoint = e.q
+        else:
+            trapezoids[1] = Trapezoid(lp, e.q, e, t.bottom)
+            trapezoids[1].update_left(e.below, t.lower_left)
+        trapezoids[2] = Trapezoid(e.q, t.rpoint, t.top, t.bottom)
+        trapezoids[2].update_left_right(trapezoids[0], trapezoids[1], t.upper_right, t.lower_right)
+        
+        return trapezoids
+  
+    def bounding_box(self, edges): 
+        margin = self.margin
+        max = edges[0].p + margin
+        min = edges[0].q - margin
+        for e in edges:
+            if e.p.x > max.x: max = Point(e.p.x + margin, max.y)
+            if e.p.y > max.y: max = Point(max.x, e.p.y + margin)
+            if e.q.x > max.x: max = Point(e.q.x + margin, max.y)
+            if e.q.y > max.y: max = Point(max.x, e.q.y + margin)
+            if e.p.x < min.x: min = Point(e.p.x - margin, min.y)
+            if e.p.y < min.y: min = Point(min.x, e.p.y - margin)
+            if e.q.x < min.x: min = Point(e.q.x - margin, min.y)
+            if e.q.y < min.y: min = Point(min.x, e.q.y - margin)
+        top = Edge(Point(min.x, max.y), Point(max.x, max.y))
+        bottom = Edge(Point(min.x, min.y), Point(max.x, min.y))
+        left = bottom.p
+        right = top.q
+        return Trapezoid(left, right, top, bottom)
+
+class Node:
+
+    parent_list = []
+    
+    def __init__(self, left, right):
+        self.left = left
+        self.right = right
+        if left is not None: 
+            left.parent_list.append(self)
+        if right is not None: 
+            right.parent_list.append(self)
+  
+    def replace(self, node):
+        for parent in node.parent_list:
+            if parent.left is node:
+                parent.left = self
+            else:
+                parent.right = self 
+            self.parent_list.append(parent)
+
+class Sink(Node):
+
+    def __new__(cls, trapezoid):
+        if trapezoid.sink is not None:
+            return trapezoid.sink
+        else:
+            return Sink(trapezoid)
+            
+    def __init__(self, trapezoid):
+        Node.__init__(self, None, None)
+        trapezoid.sink = self
+  
+    def locate(self, e): 
+        return self
+        
+class XNode(Node):
+
+    def __init__(self, point, lchild, rchild):
+        Node.__init__(self, lchild, rchild)
+        self.point = point
+        self.lchild = lchild
+        self.rchild = rchild
+    
+    def locate(self, e): 
+        if e.p.x >= self.point.x:
+            return self.right.locate(e)
+        else:         
+            return self.left.locate(e)
+
+class YNode(Node):
+
+    def __init__(self, edge, lchild, rchild):
+        Node.__init__(self, lchild, rchild)
+        self.edge = edge
+        self.lchild = lchild
+        self.rchild = rchild
+        
+    def locate(self, e):
+        if self.edge.is_above(e.p):
+            return self.right.locate(e)
+        elif self.edge.is_below(e.p):
+            return self.left.locate(e)
+        else:
+          if e.slope < self.edge.slope:
+            return self.right.locate(e)
+          else:
+            return self.left.locate(e)
+            
+class QueryGraph:
+
+    head = None
+    
+    def __init__(self, head):
+        self.head = head
+        
+    def locate(self, e):
+        return self.head.locate(e).trapezoid
+  
+    def follow_segment(self, e):
+        trapezoids = [self.locate(e)]
+        j = 0
+        while(e.q.x > trapezoids[j].right_point.x):
+            if e > trapezoids[j].right_point:
+                trapezoids.append(trapezoids[j].upper_right)
+            else:
+                trapezoids .append(trapezoids[j].lower_right)
+            j += 1
+        return trapezoids
+  
+    def replace(self, sink, node):
+        if not sink.parent_list:
+          self.head = node
+        else:
+          node.replace(sink)
+
+    def case1(self, sink, e, tlist):
+        yNode = YNode(e, Sink(tlist[1]), Sink(tlist[2]))
+        qNode = XNode(e.q, yNode, Sink(tlist[3]))
+        pNode = XNode(e.p, Sink(tlist[0]), qNode)
+        self.replace(sink, pNode)
+  
+    def case2(self, sink, e, tlist):
+        yNode = YNode(e, Sink(tlist[1]), Sink(tlist[2]))
+        pNode = XNode(e.p, Sink(tlist[0]), yNode)
+        self.replace(sink, pNode)
+  
+    def case3(self, sink, e, tlist):
+        yNode = YNode(e, Sink(tlist[0]), Sink(tlist[1]))
+        self.replace(sink, yNode)
+
+    def case4(self, sink, e, tlist):
+        yNode = YNode(e, Sink(tlist[0]), Sink(tlist[1]))
+        qNode = XNode(e.q, yNode, Sink(tlist[2]))
+        self.replace(sink, qNode)
+