add logging and main function to fancymath

src/fancymath/__main__.py

@@ -0,0 +1,36 @@
+import logging
+
+root_logger = logging.getLogger()
+
+fmt = "%(asctime)s %(levelname)-8.8s [%(name)s:%(lineno)s] %(message)s"
+formatter = logging.Formatter(fmt)
+
+sh = logging.StreamHandler()
+sh.setFormatter(formatter)
+sh.setLevel(logging.INFO)
+
+fh = logging.FileHandler("fancymath.log")
+fh.setFormatter(formatter)
+fh.setLevel(logging.NOTSET)
+
+root_logger.addHandler(sh)
+root_logger.addHandler(fh)
+
+root_logger.setLevel(logging.NOTSET)
+
+logger = logging.getLogger(__name__)
+
+logger.info("Welcome to FancyMath, a silly library for demonstrations.")
+
+from fancymath.vector import Vector
+
+v1 = Vector(1,2,3)
+v2 = Vector(2,3,4)
+
+v3 = v1.dot(v2)
+
+logger.info(f"{v1=}")
+logger.info(f"{v2=}")
+logger.info(f"{v3=}")
+
+v4 = v2.dot([1,2,3])

src/fancymath/vector.py

@@ -1,8 +1,11 @@
 """This module defines the Vector class. """
-
+import logging
 from math import acos, sqrt
 
 
+logger = logging.getLogger(__name__)
+
+
 class Vector(object):
     def __init__(self, x, y, z):
         """Constructor method."""
@@ -12,6 +15,9 @@ class Vector(object):
 
     def dot(self, v):
         """Returns the dot product with Vector *v*."""
+        if not isinstance(v, self.__class__):
+            logger.error(f"Expected an instance of {self.__class__}, but got {type(v)} instead.")
+            return None
         d = self.x * v.x + self.y * v.y + self.z * v.z
         return d