Add ability to define loops on connectors

src/output/output.dot

@@ -5,7 +5,13 @@ digraph G {
 
 
 X1[label="X1 | {{DCD|RX|TX|DTR|GND|DSR|RTS|CTS|RI} | {<p1>1|<p2>2|<p3>3|<p4>4|<p5>5|<p6>6|<p7>7|<p8>8|<p9>9}}}"]
+
 X2[label="X2 | {{<p1>1|<p2>2|<p3>3|<p4>4|<p5>5|<p6>6} | {|||||}}}"]
+
+{edge[style=bold]
+X2:p5:w -> X2:p6:w
+}
+
 W1[label="W1 | {{<w1i>1|<w2i>2|<w3i>3|<w4i>4} | {WH|BN|GN|Shield} | {<w1o>1|<w2o>2|<w3o>3|<w4o>4}}}"]
 
 {edge[style=bold]

src/test.py

@@ -3,13 +3,12 @@ import wireviz
 PINOUT_SERIAL = ('DCD','RX','TX','DTR','GND','DSR','RTS','CTS','RI')
 COLORS_WEIRD = ("infrared","ultraviolet","transparent","invisible")
 
+# example 1
 X1 = wireviz.Node("X1", pinout=PINOUT_SERIAL, ports_right=True)
 X2 = wireviz.Node("X2", num_pins=6, ports_left=True)
-
 W1 = wireviz.Cable("W1", num_wires=3, color_code="DIN", shield=True)
-
 W1.connect(X1,(2,3,5),(1,2,3),X2,(1,3,2))
-
+X2.loop(5,6)
 objects = [X1, X2, W1]
 
 with open('output/output.dot','w') as f:

src/wireviz.py

@@ -22,6 +22,7 @@ class Node:
         self.name = name
         self.ports_left = ports_left
         self.ports_right = ports_right
+        self.loops = []
 
         if pinout is None:
             self.pinout = ("",) * num_pins
@@ -32,6 +33,18 @@ class Node:
                 else:
                     self.pinout = pinout
 
+    def loop(self, from_pin, to_pin, side=None):
+        if self.ports_left == True and self.ports_right == False:
+            loop_side = 'w' # west = left
+        elif self.ports_left == False and self.ports_right == True:
+            loop_side = 'e' # east = right
+        elif self.ports_left == True and self.ports_right == True:
+            if side == None:
+                raise Exception("Must specify side of loop")
+            else:
+                loop_side = side
+        self.loops.append((from_pin, to_pin, loop_side))
+
     def __repr__(self):
         return "{} = {} {}".format(self.name, len(self.pinout), self.pinout)
 
@@ -65,6 +78,14 @@ class Node:
 
         s = s + '}}"]'
 
+        # print loops
+        if len(self.loops) > 0:
+            s = s + '\n\n{edge[style=bold]\n'
+            for x in self.loops:
+                s = s + '{name}:p{port_from}:{loop_side} -> {name}:p{port_to}:{loop_side}\n'.format(name=self.name, port_from=x[0], port_to=x[1], loop_side=x[2])
+            s = s + '}'
+
+        s = s + '\n'
         return s
 
 class Cable: