#  Demonstration code for Scientific Computing class,
#  http://www.math.nyu.edu/faculty/goodman/teaching/SciComp2022/
#  ClassDemo.py
#  uses Python 3 and Numpy
#  Python Classes Demo



import BlankSlate as bs      #  A class definition with no content
import GraySlate  as gs      #  A minimal class definition
import Helpers    as h       #  Store routines here to make the demo readible

#       Create an instance of the class with nothing.
#       See what's in it by printing its namelist
#       Add something to it and demonstrate that the thing you added is there

BlankInstance = bs.BlankSlate()   # An instance of the class with nothing

print("\nHere are all the names in the BlankInstance namespace.\n")
for name in dir(BlankInstance):
   print("   " + name)
   
print("\nHere are all the names that are not __***__.\n")
myNames = h.myNames(dir(BlankInstance))
for name in myNames:
   print("   " + name)
   
BlankInstance.printSomething = h.printHello

print("\nHere are all the names that are not __***__")
print("after adding one name\n")
myNames = h.myNames(dir(BlankInstance))
for name in myNames:
   print("   " + name)
   
print("\n When you call the function you added\n")
BlankInstance.printSomething()

#       Create an instance of the gray class with data and a function.
#       Access the data and function, manipulate the data
#       Demonstrate the "names point to objects" principle

GI3 = gs.GraySlate(3)

print("\nThe non __***__ names in an instance of the GraySlate class.")
print("These are put in by the constructor\n")

myNames = h.myNames(dir(GI3))
for name in myNames:
   print("   " + name)
   
nString = "\nGI3 has data member n ={n:2d}"
nString = nString.format( n = GI3.n )
print(nString)

x = 4
addString = "The add_n function with argument {x:2d} gives {a:2d}"
addString = addString.format( x = x, a = GI3.add_n(x) )
print(addString)

newGI   = GI3
newGI.n = 7
print("Now, GI3 has n = {n:2d}".format(n=GI3.n))