[xacml] Equivalence of Functions

[Polar Humenn <polar@syr.edu>]

foldr f a [] = a
foldr f a (x:xs) = ( f a ( foldr f a (x:xs) ) )

You could write sum of a bag of arguments in two ways:

sum []     = 0
sum (x:xs) = plus x (sum xs)

or

sum xs = foldr plus 0 xs

however, you can write product like this:

product xs = foldr multiply 0 xs

You get the functionality of "foldr" without having to define "product" or
"sum".


-Polar