57 lines
986 B
Go
57 lines
986 B
Go
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package main
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import (
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"errors"
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"fmt"
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)
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func f1(arg int) (int, error) {
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if arg == 42 {
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return -1, errors.New("can't work with 42")
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}
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return arg + 3, nil
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}
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type argError struct {
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arg int
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prob string
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}
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func (e *argError) Error() string {
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return fmt.Sprintf("%d - %s", e.arg, e.prob)
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}
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func f2(arg int) (int, error) {
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if arg == 42 {
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return -1, &argError{arg, "can't work with it"}
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}
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return arg + 3, nil
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}
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func main() {
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for _, i := range []int{7, 42} {
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if r, e := f1(i); e != nil {
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fmt.Println("f1 failed:", e)
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} else {
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fmt.Println("f1 worked:", r)
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}
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}
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for _, i := range []int{7, 42} {
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if r, e := f2(i); e != nil {
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fmt.Println("f2 failed:", e)
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} else {
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fmt.Println("f2 worked:", r)
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}
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}
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_, e := f2(42)
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if ae, ok := e.(*argError); ok {
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fmt.Println(ae.arg)
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fmt.Println(ae.prob)
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}
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}
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