Struct EvalCache 

pub struct EvalCache {
    pub data_versions: VersionTracker,
    pub params_versions: VersionTracker,
    pub entries: HashMap<String, CacheEntry>,
    pub active_item_index: Option<usize>,
    pub subform_caches: HashMap<usize, SubformItemCache>,
    pub eval_generation: u64,
    pub last_evaluated_generation: u64,
    pub main_form_snapshot: Option<Value>,
}

Primary cache structure for a JSON evaluation instance

Fields

data_versions: VersionTracker

params_versions: VersionTracker

entries: HashMap<String, CacheEntry>

active_item_index: Option<usize>

subform_caches: HashMap<usize, SubformItemCache>

eval_generation: u64

Monotonically increasing counter bumped whenever data_versions or params_versions change. When eval_generation == last_evaluated_generation, all cache entries are guaranteed valid and evaluate_internal can skip the full tree traversal.

last_evaluated_generation: u64

main_form_snapshot: Option<Value>

Snapshot of the last fully-diffed main-form data payload. Stored after each successful evaluate_internal_with_new_data call so the next invocation can avoid an extra snapshot_data_clone() when computing the diff.

Implementations

impl EvalCache

pub fn new() -> Self

pub fn clear(&mut self)

pub fn prune_subform_caches(&mut self, current_count: usize)

Remove item caches for indices >= current_count. Call this whenever the subform array length is known to have shrunk so that stale per-item version trackers and cached entries do not linger in memory.

pub fn invalidate_params_tables_for_item( &mut self, idx: usize, table_keys: &[String], )

Invalidate all $params-scoped table cache entries for a specific item.

Called when a brand-new subform item is introduced so that $params tables that aggregate array data (e.g. WOP_RIDERS) are forced to recompute instead of returning stale results cached from a prior main-form evaluation that ran when the item was absent (and thus saw zero/null for that item’s values).

pub fn needs_full_evaluation(&self) -> bool

Returns true if evaluate_internal must run (versions changed since last full evaluation)

pub fn mark_evaluated(&mut self)

Call after evaluate_internal completes successfully to mark the generation stable

pub fn set_active_item(&mut self, idx: usize)

pub fn clear_active_item(&mut self)

pub fn store_snapshot_and_diff_versions(&mut self, old: &Value, new: &Value)

Recursively diffs old against new and bumps version for every changed data path scalar.

pub fn get_active_snapshot(&self) -> Value

pub fn diff_active_item( &mut self, field_key: &str, old_sub_data: &Value, new_sub_data: &Value, )

pub fn bump_data_version(&mut self, data_path: &str)

pub fn bump_params_version(&mut self, data_path: &str)

pub fn check_cache( &self, eval_key: &str, deps: &IndexSet<String>, ) -> Option<Value>

Check if the eval_key result can be safely bypassed because dependencies are unchanged.

Two-tier lookup:

• Tier 1: item-scoped entries in subform_caches[idx] — checked first when an active item is set
• Tier 2: global self.entries — allows Run 1 (main form) results to be reused in Run 2 (subform)

pub fn store_cache( &mut self, eval_key: &str, deps: &IndexSet<String>, result: Value, )

Store the newly evaluated value and snapshot the dependency versions.

Storage strategy:

• When an active item is set, store into subform_caches[idx].entries (item-scoped). This isolates per-rider results so different items with different data don’t collide.
• The global self.entries is written only from the main form (no active item). Subforms can reuse these via the Tier 2 fallback in check_cache.

Trait Implementations

impl Clone for EvalCache

fn clone(&self) -> EvalCache

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Default for EvalCache

fn default() -> Self

Returns the “default value” for a type.