Enumerations

Pluto adds the following syntax:

pluto
enum MyEnum begin
    OPTION_1,
    OPTION_2,
    OPTION_3
end
assert(OPTION_1 == 1)
assert(OPTION_2 == 2)
assert(OPTION_3 == 3)

Enums can start at a base number, and increment from there.

pluto
enum MyEnum begin
    OPTION_1 = 0,
    OPTION_2,
    OPTION_3 = 5,
    OPTION_4
end
assert(OPTION_1 == 0)
assert(OPTION_2 == 1)
assert(OPTION_3 == 5)
assert(OPTION_4 == 6)

Since this enum has a name, we can also access its enumerators with that:

pluto
assert(MyEnum.OPTION_1 == 0)

Scoped Enums

You can force usage of the ENUM.ENUMERATOR syntax by using 'enum class':

pluto
enum class MyEnum begin
    OPTION_1,
    OPTION_2,
    OPTION_3
end
assert(OPTION_1 == nil)
assert(MyEnum.OPTION_1 == 1)

Reflection

When you have a named enum, not only can you get its enumerators, but also reflect upon it with some methods:

pluto
enum MyEnum begin
    OPTION_1,
    OPTION_2,
    OPTION_3
end
for k, v in MyEnum:kvmap() do
    print(k, v) -- "OPTION_1    1" ...
end

The following methods are available: :names(), :values(), :kvmap(), :vkmap()

Anonymous Enums

Enums can also be anonymous:

pluto
enum begin
    OPTION_1,
    OPTION_2,
    OPTION_3
end
assert(OPTION_1 == 1)
assert(OPTION_2 == 2)
assert(OPTION_3 == 3)

Using Compatibility Mode?

You may need to use pluto_enum instead of enum. Alternatively, pluto_use enum will enable the keyword independently of environment settings.