【codewar-6kyu】Function Composition

##题目描述

Function composition is a mathematical operation that mainly presents itself in lambda calculus and computability. It is explained well here, but this is my explanation, in simple mathematical notation:

f3 = compose( f1 f2 )
   Is equivalent to...
f3(a) = f1( f2( a ) )

Your task is to create a compose function to carry out this task, which will be passed two functions or lambdas. Ruby functions will be passed, and should return, either a proc or a lambda. Remember that the resulting composed function may be passed multiple arguments!

compose(f , g)(x)
=> f( g( x ) )

##思路分析

和7kyu的Unary function chainer 有点像

##代码解析

1 def compose(f,g):
2     return lambda *x: f(g(*x))

注意lambda 和 * 的用法,如果不用 lambda,则可以：

1 def compose(f,g):
2     # Compose the two functions here!
3     def apply(*x):
4         return f(g(*x))
5     return apply