proposal: spec: error != nil , add ?

[xiaokentrl]

Author background

• Would you consider yourself a novice, intermediate, or experienced Go programmer?
• experienced
• What other languages do you have experience with?
• JAVA, PHP, C#, JS

Related proposals

• Has this idea, or one like it, been proposed before?
  • YES
• Does this affect error handling?
  • NO
• Is this about generics?
  • NO

Problem
Most of the time in Go if an error occurs it can be returned. There are certain cases when this is not possible, usually go functions.

func f() (err os.Error) {
    v, err := g()
    if err != nil {
        return
    }
    if v {
        v, err := h()
        if err != nil {
            HandEorr()
        }
    }
}

Proposal

//Effect
func f() (err os.Error) {
    v, err := g() err? return
    if v {
        v, err := h() err? HandEorr()
    }
}


//Final Effect
func f() (err os.Error) {
    //if v, err := g() err? (return) {
    //if v, err := g() err return {    
    if v, err := g() err? (return) {
        v, err := h() err? HandEorr()
    }
}

//Hand Error

func main() {

    f, err := os.Open("/test.txt") err? {
       fmt.Println( err )
    }    
    
    f, err := os.Open("/test.txt") err? fmt.Println( err )
    f, err := os.Open("/test.txt") err? HandEorr( err )

    //or
    f, err := os.Open("/test.txt") err?
    fmt.Println( f )
}

? assert error

? assert  error

//or
? assert  False
//or
? assert  " "

// ---------------??------------------
?? assert  NaN         //  ? * 2

[xiaokentrl]

? assert error

? assert  error

//or
? assert  False
//or
? assert  " "

// ---------------??------------------
?? assert  NaN

[ianlancetaylor]

Thanks. Similar proposals have been made before. See #40432.

[seankhliao]

Duplicate of #33074