Enum MapMode 

#[non_exhaustive]
pub enum MapMode {
    Set,
    Append,
    Extend,
}

How a MapMapping writes a non-null result to its path.

#[non_exhaustive]: a later minor may add a spelling.

Variants (Non-exhaustive)

Non-exhaustive enums could have additional variants added in future. Therefore, when matching against variants of non-exhaustive enums, an extra wildcard arm must be added to account for any future variants.

Set

Replace the value at path (merging, when path is a context root).

Append

Push the result onto the array at path, in place.

A missing or null target becomes a one-element array; any other non-array target fails the mapping rather than being wrapped. Only the result is converted and copied, so appending costs the size of the entry, not the size of the array: the merge idiom it replaces rebuilt the whole array on every append, which made a log accumulated over a loop quadratic.

Extend

As Self::Append, pushing each element of an array result. A non-array result fails the mapping.

Trait Implementations

impl Clone for MapMode

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 MapMode

impl Debug for MapMode

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

Formats the value using the given formatter.

impl Default for MapMode

fn default() -> Self

Returns the “default value” for a type.

impl<'de> Deserialize<'de> for MapMode

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

where __D: Deserializer<'de>,

Deserialize this value from the given Serde deserializer.

impl Eq for MapMode

impl PartialEq for MapMode

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

Equality operator ==.

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

Inequality operator !=.

impl StructuralPartialEq for MapMode