### 7.5. `Pt.dist()`

: Distance between two
points

Maybe this function should overload subtraction (`.__sub__()`

)? In any case, the good old
Pythagorean theorem is all the math we need.

homcoord.py

# - - - P t . d i s t
def dist(self, other):
'''Return the distance between self and other.
'''
dx = self.x() - other.x()
dy = self.y() - other.y()
return num.sqrt ( dx*dx + dy*dy )