尾递归

尾递归

• Lua尾递归的实现

爆栈问题

基于栈实现函数调用的语言都有栈空间的上限，这里拿几个语言举例

#include 

int foo(int n){
    printf("%d\n", n);
    return foo(n+1);
}

int main()
{
    foo(1);
    return 0;
}

运行到258914次的时候出现segmentation fault

258911
258912
258913
258914
[1]    25175 segmentation fault  ./trait

def foo(n):
    print(n)
    return foo(n+1)

foo(1)

运行到992次就爆栈了

993
994
995
996
Traceback (most recent call last):
  File "trait.py", line 5, in 
    foo(1)
  File "trait.py", line 3, in foo
    return foo(n+1)
  File "trait.py", line 3, in foo
    return foo(n+1)
  File "trait.py", line 3, in foo
    return foo(n+1)
  [Previous line repeated 992 more times]
  File "trait.py", line 2, in foo
    print(n)
RecursionError: maximum recursion depth exceeded while calling a Python object

如何解决

解决爆栈的方式无非就两种

• 尾递归（Goto实现的状态机）
• 不解决

Go和lua的实现

function foo(n)
    print(n)
    return foo(n+1)
end
foo(1)

package main

import "fmt"

func foo(n int) int {
    fmt.Println(n)
    return foo(n+1)
}

func main() {
    foo(1)
}