Crate query_flow 

Query-Flow: A high-level query framework for incremental computation.

Built on top of whale, this crate provides a user-friendly API for defining and executing queries with automatic caching and dependency tracking.

Key Features

• Async-agnostic queries: Write sync query logic, run with sync or async runtime
• Automatic caching: Query results are cached and invalidated based on dependencies
• Suspense pattern: Handle async loading with AssetLoadingState without coloring functions
• Type-safe: Per-query-type caching with compile-time guarantees
• Early cutoff: Skip downstream recomputation when values don’t change

Example

use query_flow::{query, QueryContext, QueryError, QueryRuntime};

#[query]
fn add(ctx: &mut QueryContext, a: i32, b: i32) -> Result<i32, QueryError> {
    Ok(a + b)
}

let runtime = QueryRuntime::new();
let result = runtime.query(Add::new(1, 2)).unwrap();
assert_eq!(*result, 3);

Modules

output_eq

Utility functions for output equality comparison in queries.

Structs

AssetLoadingState

Loading state with asset key information for error reporting.

FullCacheKey

Full cache key that includes query type information.

PendingAsset

A pending asset request that needs to be resolved.

Polled

Result of polling a query, containing the value and its revision.

QueryContext

Context provided to queries during execution.

QueryRuntime

The query runtime manages query execution, caching, and dependency tracking.

QueryRuntimeBuilder

Builder for QueryRuntime with customizable settings.

Enums

DurabilityLevel

Named durability levels for assets and queries.

LocateResult

Result of locating an asset.

QueryError

Query errors including both system-level and user errors.

Traits

AssetKey

Trait for asset keys that map to loadable assets.

AssetLocator

Trait for locating and loading assets.

Key

Trait for query cache keys.

Query

A query that can be executed and cached.

Type Aliases

ErrorComparator

Function type for comparing user errors during early cutoff.

RevisionCounter

Revision counter type - monotonically increasing counter for tracking changes.

Attribute Macros

asset_key

Define an asset key type.

query

Define a query from a function.