Module transform 

Reactive transform primitives for derived records

This module provides the .transform() and .transform_join() API for declaring reactive derivations from one or more input records to an output record.

Transform Archetypes

• Map (1:1, stateless): Transform each input value to zero-or-one output value
• Accumulate (N:1, stateful): Aggregate a stream of values with persistent state
• Join (M×N:1, stateful, multi-input): Combine values from multiple input records

All three are handled by a unified API surface:

• Single-input: .transform() with TransformBuilder
• Multi-input: .transform_join() with JoinBuilder

Design Principles

• Transforms are owned by AimDB — visible in the dependency graph
• Transforms are mutually exclusive with .source() on the same record
• Multiple .tap() observers can still be attached to a transform’s output
• Input subscriptions use existing Consumer<T, R> / BufferReader<T> API
• Build-time validation catches missing input keys and cyclic dependencies

Structs

JoinBuilder

Type-erased input descriptor for joins.

JoinPipeline

Completed multi-input join pipeline, ready to be stored in TypedRecord.

JoinStateBuilder

Intermediate builder for setting the join trigger handler.

StatefulTransformBuilder

Intermediate builder for stateful single-input transforms.

TransformBuilder

Configures a single-input transform pipeline.

TransformPipeline

Completed single-input transform pipeline, ready to be stored in TypedRecord.

Enums

JoinTrigger

Tells the join handler which input produced a value.