Enum OnNull 

#[non_exhaustive]
pub enum OnNull {
    Skip,
    Unset,
}

What a MapMapping does when its logic evaluates to null.

#[non_exhaustive]: a later minor may add a spelling — writing an explicit null, say, which no mapping can do today.

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.

Skip

Leave the path as it was. A var that misses and an if with no matching branch both produce null, so skipping is what keeps a missing source from wiping its target — and what makes {"if": [cond, value, null]} mean “set or keep”.

Unset

Remove the key at path, exactly as MapMapping::unset would: {"if": [cond, value, null]} then means “set or clear”.

Trait Implementations

impl Clone for OnNull

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 OnNull

impl Debug for OnNull

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

Formats the value using the given formatter.

impl Default for OnNull

fn default() -> Self

Returns the “default value” for a type.

impl<'de> Deserialize<'de> for OnNull

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

where __D: Deserializer<'de>,

Deserialize this value from the given Serde deserializer.

impl Eq for OnNull

impl PartialEq for OnNull

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

Equality operator ==.

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

Inequality operator !=.

impl StructuralPartialEq for OnNull