Coding, “the crappy way”

I was talking to my friend Tristan the other day, via the MUD which he has created and programmed himself. If you don’t know what a MUD (Multi User Dungeon) is, it’s a sort of a text based adventure world where you can interact with other people, and move between various rooms and locations, and interact with various objects. If you are about my age you probably remember those books in which you read a paragraph and then at the bottom it gives you a choice of “go to page 46” or “go to page 32” – at which point you secretly keep your finger in the original page just in case your choice of page 46 leads to you being eaten horribly by some kind of dragon. It’s a bit like World of Warcraft with no graphics, or an IRC client with dragons – take your pick.

I digress.

Near the start of this year, I had suggested that students have a go at creating their own text based adventure game as an early task in Python. I gave them this code as a template, and asked them to continue:

# Python adventure game

# Define the direction variable
direction1 = ''

# Print out a statement setting the scene for the user
print """As you step into the cave you can smell musty cobwebs and the
dank odour of dripping water. At the back of the cave the path forks
and you can see two directions to travel, left and right."""

# Keep doing this until they have entered either left or right
while direction1 not in ["left","right"]:

    # Ask the user where they want to go
    direction1 = raw_input("Do you want to go left or right?: ")

    # Decide what happens 
    if direction1 == "left":
        print "\nYou have entered the bear's lair!"
        print "Sadly all that is left of you is a pile of bones."
    elif direction1 == "right":
        print "\nThe back of this passage seems to lead somewhere..."
    else:
        print "That is not a direction"

I’m not afraid to admit, this was not one of my finer tasks because it doesn’t take a genius to figure out (but perhaps this did not occur to a sleep deprived teacher) that very quickly you are going to get in a huge muddle of where you are, which direction you can go in and which you can’t – let alone add in usable items and an inventory! Still, it was a nice practice of lots and lots of nested if statements…

I thought I’d ask Tristan how he would go about solving this problem – and his first response was that he’d use classes. Spanner in the works then, because I told him that we don’t seem to cover any Object Oriented programming at all at AS Level. His second idea was to use the dictionary construct in Python, which is different to the list construct which I usually use to teach arrays, because it allows you to use string keys. (Of course, if PHP were a supported language of the exam board, we wouldn’t have to bother with either we’d just use arrays *grumble* :D) This seemed like a pretty good idea, and we discussed how we would go about it, with the discussion coming to a close on his comment of

“well you do know this is the crappy way of doing it?”

This got me thinking…a lot of the time when we are teaching programming, we are actually teaching “the crappy way” of doing something – and not the way that a real life programmer would approach it. Sometimes this is because the crappy way of doing it is actually more understandable to the learner…a prime example of this which comes to mind is in PHP when you extract all items from an array (most commonly a query result) into variables with the key names. e.g.

$fruit = array("orange" => 1, "apple" => 2, "pear" => 1);
extract($fruit);
print $orange;
// Output will be 1

I suspect that most experienced programmers would not use this much (and especially not on form data!) but often it’s easier to just suggest doing it to avoid the hassle of explaining how to use array keys and then getting a blank look. Even though you’ve covered arrays for approximately 4 weeks and done 10 past papers on it. I exaggerate.

So is this a bad thing? I remember being rather miffed in Science lessons when I was in school that we would be taught something in Year 7, and then the next year they would say “well that’s not completely true, it’s actually like this”…and so on. As much as I cringe a little bit inside every time I have to do it, I don’t think that teaching some things “the crappy way” is necessarily bad. I’m not saying that we should forget good habits like variable names, indentation, and algorithm efficiency – far from it – but as long as they are aware that there are other ways of achieving the same result, you are still teaching a method which works. It’s not the most efficient way, but it gives the students a starting point to work from rather than totally confusing them and making them feel like they’ll never be any good and might as well pack up now. That’s why we are teachers, that’s why we are here – to teach the foundations of the subject and to ignite an interest in programming, not to make a legion of perfect programmers. If they are interested enough to go and look up how things could be done more efficiently and properly, and tell you off for your terrible code – GREAT! Our work here is done. If not, at least their program worked. 🙂 At present I have one of my Lower 6th classes picking me up on EVERY piece of bad coding, poor variable naming, or general mistakes they possibly can, and I LOVE IT!!!

Oh and in case you’re wondering, here’s the foundations of the text adventure game, using the dictionary constructs in Python

# Python adventure game using dictionaries

# Validate their input direction

def input_direction():
    direction = raw_input("Which direction do you want to go? ")
    while direction not in ["north", "south", "east", "west", "exit"]:
        direction = raw_input("Which direction do you want to go ")

    return direction

# ---------------------------------------------
# Set up the rooms

compass = dict({ "north" : {0: 1, 1:2, 2:-1},
                 "south": {0: -1, 1:0, 2:1}
                })

descr = dict({0: "You are in a small lobby type room.",
              1: "You are in a grand hall way",
              2: "You are in a huge palace"})

currentRoom = 0
newDir = ""

# Game loop
while( currentRoom != -1 ):

    # Describe the current room
    print descr[currentRoom]

    # Ask what they want to do
    newDir = input_direction()

    # If they wish to exit
    if newDir == "exit":
        print "See ya later, alligator!"
        currentRoom = -1
    else:

        # Otherwise look up whether there is a path that way
        if compass[newDir][currentRoom] != -1:
            currentRoom = compass[newDir][currentRoom]
        else:
            print "There is no path in that direction"

In case you are interested, a link to Tristan’s MUD