Crate bhc_query 

Query-based compilation system for BHC.

This crate provides the infrastructure for incremental, demand-driven compilation using a query-based architecture similar to rustc’s query system and salsa.

Overview

The query system allows the compiler to:

• Incrementally recompute only what has changed between compilations
• Demand-driven evaluation where queries are only computed when needed
• Automatic memoization of query results
• Cycle detection for recursive queries

Architecture

Queries are defined as traits that can be implemented by a database. The database stores memoized results and tracks dependencies between queries.

┌─────────────────────────────────────────────────────┐
│                    QueryDatabase                     │
│  ┌─────────────┐  ┌─────────────┐  ┌─────────────┐ │
│  │  Query A    │  │  Query B    │  │  Query C    │ │
│  │  (cached)   │──│  (cached)   │──│  (pending)  │ │
│  └─────────────┘  └─────────────┘  └─────────────┘ │
│                    Dependencies                      │
└─────────────────────────────────────────────────────┘

Structs

MemoizedResult

A memoized query result with revision tracking.

QueryId

A unique identifier for a query invocation.

QueryRuntime

A runtime for executing queries with a database.

QueryStorage

Storage for a specific query type.

Revision

A revision number tracking database state changes.

SimpleDatabase

A simple in-memory query database implementation.

Enums

QueryError

Error types for the query system.

QueryState

The state of a query computation.

Traits

InputQuery

Marker trait for input queries that can be set directly.

Query

A query definition with its computation function.

QueryDatabase

The central database trait that all query databases must implement.

QueryKey

Trait for types that can be used as query keys.

QueryValue

Trait for types that can be used as query values.

Type Aliases

QueryResult

Result type for query computations.