Sorry, I forgot to mention the point of the game. Person B is supposed 
to figure out what function person A is using.

Pal-Kristian Engstad wrote:
> Vincent Aravantinos wrote:
>> Those are typically the comments of a 
>> "used-to-functional-programming" guy.
>> It certainly doesn't match what a beginner would think (no beginner 
>> will call a
>> function a "value").
> This reminds me of a "game" I used to teach my math students the 
> concept of a function. I think it should be able to be used for an 
> introductory computer science class as well.
>
> Essentially, the game involves having person A come up with a rule. 
> Person B will have to provide an input value, and A has to faithfully 
> give the result of the rule/computation. Examples of functions could 
> be \x->x+2, \x->2*x, etc. More interesting examples involves the 
> function that returns the first letter of the name of the input (f 
> "one" = "o"), or the successor of a "red, yellow, green" traffic light 
> symbol.
>
> When doing this, A and B will quickly have to agree on the allowed 
> input values (the domain) and in order to have a chance it is also 
> helpful if B knows the range of output values (the image). And for 
> sure - they will have to agree that the rule x = y => f(x) = f(y) has 
> to hold in order to be able to guess what "f" is. [I would also 
> disallow closures for this game - otherwise it would be too hard to 
> guess.]
>
> The reason this exercise is good is that it teaches the students (in a 
> fun way) the important concepts behind a function. It will make them 
> understand that a function is just a computation, but also point out 
> the importance of defining the types (sets) of inputs and outputs. I 
> think that after playing this game, you can venture to talk about the 
> "name" of the function, and they will realize that it does not matter 
> what the name of the function is - just what it does.
>
> Perhaps after this, you can teach the concept of treating a function 
> as a value, or input to another function? Person A makes a function 
> that takes person B's function, etc.
>
> Thanks,
>
> PKE
>

-- 
Pål-Kristian Engstad (engstad@naughtydog.com), Lead Graphics & Engine Programmer,  
"Uncharted"-team, Naughty Dog, Inc., 1601 Cloverfield Blvd, 6000 North,
Santa Monica, CA 90404, USA. Ph.: (310) 633-9112.

"Most of us would do well to remember that there is a reason Carmack
is Carmack, and we are not Carmack.",
                       Jonathan Blow, 2/1/2006, GD Algo Mailing List