error is an interface in Go

One method, Error() string — anything with it is an error.

func divide(a, b float64) (float64, error) {
    if b == 0 {
        return 0, errors.New("divide by zero")
    }
    return a / b, nil
}

func report() string {
    if _, err := divide(1, 0); err != nil {
        return "failed: " + err.Error()
    }
    return "ok"
}

How it works

1. A function returns its error last, by convention.
2. nil means success; check it before using the other results.
3. errors.New is enough when there is nothing to carry.

Keywords and builtins used here

• error
• float64
• func
• if
• return
• string

The run, in numbers

Lines

13

Characters to type

229

Tokens

70

Three-star pace

95 tpm

At the three-star pace of 95 tokens a minute, this run takes about 44 seconds.

Type this snippet

Step 1 of 3 in The error value, step 1 of 15 in Errors.

Next →