trycatch-deferpanicrecover.go

// Attempting to write try-catch pattern
// with defer, panic, and recover in golang
// Built upon https://blog.golang.org/defer-panic-and-recover

package main

import "fmt"

func main() {
    container()
    fmt.Println("Try complete")
}

func container() {
    // Only run recovery() when container() returns
    // If recovery() is omitted, panic() exits the program and prints the stack trace
    defer recov()

    // Try for values of i = 0
    fmt.Println("Trying")
    tryer(0)
    fmt.Println("Return normally from tryer")
}

func recov() {
    if r := recover(); r != nil {
        fmt.Println("Recovered in try", r)
    }
}

func tryer(i int) {
    // Panics (catches) for values where i > 3
    if i > 3 {
        fmt.Println("Panicking!")
        panic(fmt.Sprintf("Panicking! %v", i))
    }
    // This executes when the current tryer() function returns
    defer fmt.Println("Returning try no.", i)
    fmt.Println("Values tried:",i)

    // Recurse
    // (Why not a loop?)
    tryer(i+1)
}