Maven中的“反应堆”是什么？(What is the “reactor” in Maven?)

 好吧，让我们首先使用缩进来让函数定义更加清晰 
 
let f x y =
     if y/=0
         then f (x+1) (y-1)
         else x
in f 3 5
 
 所以f首先被调用参数3和5 。 y是5（即不是0），则执行该分支，该分支使用参数4和4调用f。 由于y仍然不等于0，我们再次进入then分支并用参数5和3调用f。 这继续下去，直到我们最终以x = 8和y = 0调用f。 然后我们进入条件的else分支，它只返回x ，即8。 
 
 下面是可以减少表达式f 3 5一种方式： 
 
f 3 5 -- y /= 0, so we go into the then branch
=> f (3 + 1) (5 - 1)
=> f 4 4 -- then branch again
=> f (4 + 1) (4 - 1)
=> f 5 3
=> f (5 + 1) (3 - 1)
=> f 6 2
=> f (6 + 1) (2 - 1)
=> f 7 1
=> f (7 + 1) (1 - 1)
=> f 8 0 -- this time we go into the else branch
=> 8

Ok, so let's first make the function definition a bit more clear by using indentation
 
let f x y =
     if y/=0
         then f (x+1) (y-1)
         else x
in f 3 5
 
So f is called with arguments 3 and 5 at first. y being 5 (i.e. not 0), the then branch is executed, which calls f with arguments 4 and 4. Since y is still not equal to 0, we go into the then branch again and call f with arguments 5 and 3. This goes on until we finally call f with x = 8 and y = 0. We then go into the conditional's else branch, which just returns x, i.e. 8.
 
Here is one way the expression f 3 5 could be reduced:
 
f 3 5 -- y /= 0, so we go into the then branch
=> f (3 + 1) (5 - 1)
=> f 4 4 -- then branch again
=> f (4 + 1) (4 - 1)
=> f 5 3
=> f (5 + 1) (3 - 1)
=> f 6 2
=> f (6 + 1) (2 - 1)
=> f 7 1
=> f (7 + 1) (1 - 1)
=> f 8 0 -- this time we go into the else branch
=> 8