aiondb-eval

Expression evaluator and runtime helpers shared between the planner, optimizer and executor. Owns the scalar function registry, value coercions, hash-key construction, regex cache, async-notify queue, statement cancellation flag, and the per-thread session context (search path, datestyle, timezone, current database, etc.) that scalar functions read from.

cargo

[dependencies]
aiondb-eval = { path = "../aiondb-eval" }

modules

module	purpose
`eval`	`ExpressionEvaluator` and the bulk of the evaluator (`mod`, `cast`, `operators`, `scalar_functions`, `domain_check`, `pg_format`, `session`, `temporal_precision`, `money`).
`coercions`	`coerce_value` - run-time value-to-type coercion.
`functions`	Scalar function registry (`FunctionRegistry`, `FunctionInfo`).
`hash_key`	`build_hash_key`, `ValueHashKey` - canonical hashing for grouping and joins.
`cancel`	Statement cancellation flag.
`async_notify`	Backing queue for `LISTEN` / `NOTIFY`.

key types

ExpressionEvaluator - zero-sized struct with the evaluation entry points: evaluate(&TypedExpr), evaluate_with_row(&TypedExpr, &Row), plus resolver-driven variants for correlated subqueries.
EvalSessionContext, EvalTemporalSessionContext - session-scoped state read by scalar functions.
FunctionRegistry, FunctionInfo - scalar function dispatch.
ValueHashKey - hashable wrapper over Value for hash joins and aggregation.
CompatCastContext, CompatCastMethod, CompatUserCast, CompatUserType, CompatUserTypeField, DomainConstraint, DomainDef - PG-compatible cast / domain machinery.
ClusterDatabaseSummary - snapshot of cluster-wide database state used by pg_database / pg_stat_database virtual tables.

session and registry hooks

item	role
`with_session_context(ctx, f)`	Run `f` with `ctx` installed as the current per-thread session context.
`current_session_context()`	Return the active context, if any.
`current_search_path_schemas()`, `current_database_name()`, `current_schema_name()`, `current_time_zone()`, `current_date_order()`, `current_interval_style()`, `current_lo_session_key()`, `current_temporal_session_context()`	Convenience accessors.
`set_extension_registry(reg)`, `with_extension_registry(reg, f)`, `extension_registry()`	Per-thread extension registry (`aiondb_extension::ExtensionRegistry`).
`enter_inlining_user_function(name)`, `is_inlining_user_function(name)`	Recursion guard used by the planner when inlining `CREATE CAST WITH FUNCTION` overrides.
`register_pg_statistics_objdef(oid, def)`, `lookup_pg_statistics_objdef(oid)`	`pg_statistic_ext` object-definition registry.

file-system scalar helpers

function	role
`eval_pg_ls_dir_with_base_dir`	Backing for `pg_ls_dir`.
`eval_pg_read_file_with_base_dir`	Backing for `pg_read_file`.
`eval_pg_read_binary_file_with_base_dir`	Backing for `pg_read_binary_file`.

All three accept the engine-supplied data directory so the evaluator never reads outside the cluster root.

example

use aiondb_core::{DataType, Value};
use aiondb_eval::ExpressionEvaluator;
use aiondb_plan::TypedExpr;

let evaluator = ExpressionEvaluator;
let lit = TypedExpr::literal(Value::Int(7), DataType::Int, false);
let v = evaluator.evaluate(&lit).expect("evaluate");
assert_eq!(v, Value::Int(7));