Enum MergeStrategy 

pub enum MergeStrategy {
    LastWins,
    Concatenate,
    SubmoduleMerge,
    AttrsetMerge,
    Disjoint,
    Custom,
    AnyLastWins,
}

How multiple definitions of one option fold into one value.

The cppnix lattice is small: most types are last-wins under priority resolution; listOf concatenates after priority; the submodule + attrsOf variants recurse. Custom merges plug in via a named hook the interpreter resolves.

Variants

LastWins

One definition wins by priority order (bool, int, str, path, package, null, enum). Tie at top priority is a typeError.

Concatenate

Concatenate lists in priority order (listOf T). Elements from higher priorities come first.

SubmoduleMerge

Recursive submodule eval — apply the module algorithm to the definitions of this option (submodule).

AttrsetMerge

Deep-merge attrsets — recurse on overlapping keys, set-union on disjoint (attrsOf T, plain attrs).

Disjoint

At most one definition allowed; multiple = typeError (oneOf after dispatch).

Custom

Plug-in merge function named by string; the interpreter resolves the name to a builtin or a user-supplied function. Used for lib.types.either, lib.types.functionTo, etc.

AnyLastWins

any-typed: accept any value, last-wins. Unsafe; only permitted for the any option type explicitly.

Trait Implementations

impl Clone for MergeStrategy

fn clone(&self) -> MergeStrategy

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Copy for MergeStrategy

impl Debug for MergeStrategy

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

Formats the value using the given formatter.

impl<'de> Deserialize<'de> for MergeStrategy

fn deserialize<__D>(__deserializer: __D) -> Result<Self, __D::Error>

where __D: Deserializer<'de>,

Deserialize this value from the given Serde deserializer.

impl Eq for MergeStrategy

impl PartialEq for MergeStrategy

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

Tests for self and other values to be equal, and is used by ==.

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

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl Serialize for MergeStrategy

fn serialize<__S>(&self, __serializer: __S) -> Result<__S::Ok, __S::Error>

where __S: Serializer,

Serialize this value into the given Serde serializer.

impl StructuralPartialEq for MergeStrategy