Enum EnumeratorValue 

pub enum EnumeratorValue {
    Declared,
    Ordinal,
}

Which integer an enumerator serialises as.

XTypes 1.3 §7.4.3.5.3 rule (5) is XCDR << {O : ENUM_TYPE} = XCDR << { O.value : O.holder_type }, and IDL 4.2 §7.4.13 gives O.value as the @value(n) the enumerator declares, else the previous enumerator’s value plus one, starting at zero. So the clause has an answer, and it is Self::Declared.

What is measured

Two front ends drop @value and number the enumerators by position, and 40 recorded rows differ by exactly that. enum-negative-value, enum-sparse-values, enum-bitbound-{8,16,32}-value and their unannotated twins, OpenDDS, both encoding versions and both byte orders — the same length in every row, and the first differing octet is octet 0:

enum-negative-value    @value(-1) MINUS, @value(0) ZERO, @value(2147483647) MAX
  ours    ffffffff 7fffffff
  theirs  00000000 00000002

enum-sparse-values     @value(1) OK, @value(100) WARN, @value(65535) FAIL
  ours    0000ffff 00000001 00000064
  theirs  00000002 00000000 00000001

enum-bitbound-8-value  @value(3) RED, @value(9) GREEN, @value(200) BLUE
  ours    000000c8 00000009 ab
  theirs  00000002 00000001 ab

opendds_idl answers error in lookup of symbol: bit_bound and the same for value; tao_idl drops the annotation the same way — docs/wire-feature-inventory.md row E1, and warnings.rs::CLASSIFICATION already carries the warning with carried_into: "E1". Cyclone, RTI and Fast DDS all carry @value. Two front ends dropping the annotation and three carrying it is the same shape as EnumHolderWidth, and it takes the same answer: not an axis by judgement 3, and a setting all the same, because a peer that writes the ordinal writes the ordinal whatever the reason and a reader of the declared value is reading a different enumerator.

It is not the holder’s width, and the corpus separates them

The two questions look like one on enum-bitbound-8-value, where OpenDDS’s octets differ from this project’s in both. They are not: enum-negative-value declares no @bit_bound at all and still differs, and enum-bitbound-8-plain declares @bit_bound(8) with no @value and is closed by EnumHolderWidth alone. The 16 rows of enum-bitbound-{8,16}-value need both — the four-octet holder and the ordinal — which is why EnumHolderWidth closed 76 rows and not the 92 an estimate gave, and why those 16 were the difference between the causes named for OpenDDS and the rows measured open.

It is not a planner setting

The holder’s width does not change, so no offset moves and no EMHEADER length code changes. It stays out of LayoutKey::offset_key for the same reason MapEntryOrder and UnionLabelMatch do.

It is a reader setting

Unlike MapEntryOrder. All 40 rows reach a reader: a peer’s 00000002 is BLUE’s ordinal and this project’s MAX’s declared value, and a decoder that took the pattern for a declared value would name a different enumerator or none at all.

No dialect selects the second value

For the reason EnumHolderWidth::BitBoundDroppedByFrontEnd is not selected either: OpenDDS and TAO are recorded peers here rather than presets, and a front-end defect is not a reading of §7.4.3.5.3. --enumerator-value ordinal reaches it.

Variants

Declared

The value IDL 4.2 §7.4.13 gives: @value(n), else the previous enumerator’s value plus one, from zero.

The default, and what Cyclone, RTI and Fast DDS write.

Ordinal

The enumerator’s position in its declaration, from zero, whatever @value says.

What a front end that does not know the annotation writes. Identical to Self::Declared for an enumeration that declares no @value — which is every enumeration in the corpus but five — so the setting is invisible except where the annotation is.

Implementations

impl EnumeratorValue

pub const ALL: [Self; 2]

Both.

pub const fn is_default(self) -> bool

Whether this is the default.

pub const fn as_str(self) -> &'static str

Short name, for configuration and diagnostics.

pub fn parse(value: &str) -> Option<Self>

Parse a configuration value.

An unknown value returns None rather than falling back to the default: a typo in a wire-affecting setting must be loud.

Trait Implementations

impl Clone for EnumeratorValue

fn clone(&self) -> Self

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Copy for EnumeratorValue

impl Debug for EnumeratorValue

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Default for EnumeratorValue

fn default() -> Self

Returns the “default value” for a type.

impl Eq for EnumeratorValue

impl Hash for EnumeratorValue

fn hash<__H: Hasher>(&self, state: &mut __H)

Feeds this value into the given Hasher.

fn hash_slice<H>(data: &[Self], state: &mut H)

where H: Hasher, Self: Sized,

Feeds a slice of this type into the given Hasher.

impl Ord for EnumeratorValue

fn cmp(&self, other: &Self) -> Ordering

This method returns an Ordering between self and other.

fn max(self, other: Self) -> Self

where Self: Sized,

Compares and returns the maximum of two values.

fn min(self, other: Self) -> Self

where Self: Sized,

Compares and returns the minimum of two values.

fn clamp(self, min: Self, max: Self) -> Self

where Self: Sized,

Restrict a value to a certain interval.

fn clamp_to<R>(self, range: R) -> Self

where Self: Sized, R: ClampBounds<Self>,

🔬This is a nightly-only experimental API. (clamp_to)

Restrict a value to a certain range.

impl PartialEq for EnumeratorValue

fn eq(&self, other: &Self) -> bool

Equality operator ==.

fn ne(&self, other: &Rhs) -> bool

Inequality operator !=.

impl PartialOrd for EnumeratorValue

fn partial_cmp(&self, other: &Self) -> Option<Ordering>

This method returns an ordering between self and other values if one exists.

fn lt(&self, other: &Rhs) -> bool

Tests less than (for self and other) and is used by the < operator.

fn le(&self, other: &Rhs) -> bool

Tests less than or equal to (for self and other) and is used by the <= operator.

fn gt(&self, other: &Rhs) -> bool

Tests greater than (for self and other) and is used by the > operator.

fn ge(&self, other: &Rhs) -> bool

Tests greater than or equal to (for self and other) and is used by the >= operator.

impl StructuralPartialEq for EnumeratorValue