Conversions in Go

Go converts explicitly: no implicit promotion, ever.

type Celsius float64

func conversions(text string) (int, string, Celsius, error) {
    big := 300
    asByte := byte(big % 256) // explicit, and it wraps

    parsed, err := strconv.Atoi(text)
    if err != nil {
        return 0, "", 0, fmt.Errorf("parse %q: %w", text, err)
    }

    formatted := strconv.FormatFloat(1.5, 'f', 2, 64)
    temperature := Celsius(float64(parsed))

    return int(asByte) + parsed, formatted, temperature, nil
}

How it works

1. A numeric conversion can silently truncate, so bound it first.
2. strconv converts between strings and numbers, with an error.
3. A named type needs a conversion even when the underlying type matches.

Keywords and builtins used here

• byte
• error
• float64
• func
• if
• int
• return
• string
• type

The run, in numbers

Lines

16

Characters to type

405

Tokens

101

Three-star pace

80 tpm

At the three-star pace of 80 tokens a minute, this run takes about 76 seconds.

Type this snippet

Step 4 of 5 in Variables & types, step 4 of 30 in Language basics.

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