Appends a String representation of this enum member to the given io.

See also: #to_s.

Returns a String representation of this enum member. In the case of regular enums, this is just the name of the member. In the case of flag enums, it's the names joined by vertical bars, or "None", if the value is zero.

If an enum's value doesn't match a member's value, the raw value is returned as a string.

Color::Red.to_s                     # => "Red"
IOMode::None.to_s                   # => "None"
(IOMode::Read | IOMode::Write).to_s # => "Read | Write"

Color.new(10).to_s # => "10"

Serializes this enum member by name.

For non-flags enums, the serialization is a YAML string. The value is the member name (see #to_s) transformed with String#underscore.

enum Stages
  INITIAL
  SECOND_STAGE
end

Stages::INITIAL.to_yaml      # => %(--- initial\n)
Stages::SECOND_STAGE.to_yaml # => %(--- second_stage\n)

For flags enums, the serialization is a YAML sequence including every flagged member individually serialized in the same way as a member of a non-flags enum. None is serialized as an empty sequence, All as a sequence containing all members.

@[Flags]
enum Sides
  LEFT
  RIGHT
end

Sides::LEFT.to_yaml                  # => %(--- [left]\n)
(Sides::LEFT | Sides::RIGHT).to_yaml # => %(--- [left, right]\n)
Sides::All.to_yaml                   # => %(--- [left, right]\n)
Sides::None.to_yaml                  # => %(--- []\n)

ValueConverter.to_yaml offers a different serialization strategy based on the member value.