Convert panic to returned error

---

examples/deep-panic-return/deep_panic_return.go

package main

import (
    "fmt"
)

func main() {
    fmt.Println("Before")
    fmt.Println()

    dividend := 16
    divisors := []int{8, 4, 0, 2}
    for _, divisor := range divisors {
        res, err := mydiv(dividend, divisor)
        if err != nil {
            fmt.Printf("Error: %v\n", err)
            continue
        }
        fmt.Println(res)
    }

    fmt.Println()
    fmt.Println("After")
}

func mydiv(a, b int) (res int, myerr error) {
    // var res int
    // var err error

    defer func() {
        if err := recover(); err != nil {
            //fmt.Printf("Error: %v\n", err)
            myerr = fmt.Errorf("%v", err)
            //log.Print("Error: ", err)
            //panic(err)
        }
    }()
    res = externalDiv(a, b)
    return
}

func externalDiv(a, b int) int {
    res := a / b
    return res
}

Before

2
4
Error: runtime error: integer divide by zero
8

After