字符串类型声明与字符串不具有可比性

Question

I've got an alias type "LogLevel" which is a string:

type LogLevel string

const (
    InfoLevel  LogLevel = "info"
    DebugLevel LogLevel = "debug"
    WarnLevel  LogLevel = "warn"
    ErrorLevel LogLevel = "error"
    PanicLevel LogLevel = "panic"
    FatalLevel LogLevel = "fatal"
)

Now I'd like to do a switch case to check these consts against user input:

    switch strings.ToLower(input) {
    case "", InfoLevel:
        return zap.NewAtomicLevelAt(zap.InfoLevel)
    default:
        fmt.Errorf("Invalid log level supplied '%s'. Defaulting to info loglevel", input)
        return zap.NewAtomicLevelAt(zap.InfoLevel)
    }

This doesn't work because apparently the types are incompatible?

invalid case InfoLevel in switch on strings.ToLower(input) (mismatched types LogLevel and string)

How can I use the defined consts in the cases?

Answer 1

One of the operands in an comparison must be assignable to the other. The type string is not assignable to LogLevel and vice versa. To get comparable values, convert the string to a LogLevel:

switch LogLevel(strings.ToLower(input)) {