Enum StateChange 

pub enum StateChange {
    Assign {
        values: Map<String, Value>,
    },
    Append {
        values: Vec<(String, Value)>,
    },
    Extend {
        values: Vec<(String, Vec<Value>)>,
    },
    Increment {
        values: Vec<(String, Value)>,
    },
    Remove {
        keys: Vec<String>,
    },
    Wipe {
        keep: Vec<String>,
    },
    Merge {
        state: WorkflowState,
    },
    Subset {
        keys: Vec<String>,
    },
}

A resolved immutable state operation; expressions remain private syntax.

Each payload is one atomic operation with at most 4,096 entries. Repeated Append/Extend/Increment keys apply in order; any later failure discards the whole candidate. Merge and Subset use full-state validation rather than primitive transition callbacks. Results never mutate the original state.

Variants

Assign

Replaces values atomically in payload order, preserving existing positions.

Fields

values: Map<String, Value>

Complete values to replace or insert.

Append

Appends one item per entry, creating arrays for missing keys.

Fields

values: Vec<(String, Value)>

Ordered entries; repeated keys append repeatedly within one operation.

Extend

Extends arrays atomically without recursively flattening their items.

Fields

values: Vec<(String, Vec<Value>)>

Ordered entries; repeated keys preserve every supplied item.

Increment

Adds signed integer deltas to integer values, or zero for missing keys.

Fields

values: Vec<(String, Value)>

Ordered deltas, each representable as i64; repeated keys fold in order.

Remove

Removes keys atomically, preserving the order of other keys.

Fields

keys: Vec<String>

Missing and repeated names are harmless.

Wipe

Keeps keys in their existing order; typing observes resolved Remove keys.

Fields

keep: Vec<String>

Keys to retain; missing and repeated names are harmless.

Merge

Replaces overlapping values and appends new keys in incoming order.

Fields

state: WorkflowState

Values to merge into the current state.

Subset

Selects present keys in the requested order.

Fields

keys: Vec<String>

Ordered keys to select; missing keys are ignored.