Enums

An enum is a fixed set of named values. Use one when a script has a few modes, and you want the settings gear to offer them as a dropdown.

//@version=5
indicator("Average type", overlay = true)

enum Kind
    ema = "Exponential"
    sma = "Simple"
    wma

kind = input.enum(Kind.ema, "Average")
len = input.int(20, "Length")
avg = switch kind
    Kind.ema => ta.ema(close, len)
    Kind.sma => ta.sma(close, len)
    => ta.wma(close, len)
plot(avg, "Average")

Defining one

enum Name is followed by an indented list of values. Each is a name, or a name with a title in quotes: sma = "Simple". The title is what people see in the dropdown and what str.tostring gives. Without a title, the name is used. An enum is defined at the top level of the script.

Using the values

Write a value as Kind.ema.
Compare with == and !=, or choose with switch, as above.
A value can be a field of a type, a function argument, or a map key.
input.enum(default, title, options) makes the dropdown. Pass options = [Kind.ema, Kind.sma] to offer only some values. The default has to be one of them.

The saved setting is the value's name, so renaming a value in the script resets that setting to the default.