M.V. Hutz
1974ad582f
## Description This PR completes the MVC-inspired refactoring by moving the event system from the engine into the reducer. The engine package is now removed entirely, as the reducer handles both reduction logic and lifecycle events. - Add `pkg/reducer/events.go` with `StartEvent`, `StepEvent`, and `StopEvent`. - Extend `Reducer` interface to embed `Emitter[Event]` and add `Expression()` method. - Update `NormalOrderReducer` to embed `BaseEmitter` and emit lifecycle events during reduction. - Update all plugins to attach to `Reducer` instead of `Engine`. - Remove `internal/engine` package entirely. - Add `Off()` method to `BaseEmitter` to complete the `Emitter` interface. - Fix `Emitter.On` signature to use generic type `E` instead of `string`. ### Decisions - The `Reducer` interface now combines reduction logic with event emission, making it the single orchestration point. - Plugins attach directly to the reducer, simplifying the architecture. - The `Expression()` method on `Reducer` provides access to current state for plugins. ## Benefits - Simpler architecture with one fewer abstraction layer. - Plugins are now mode-agnostic - they work with any `Reducer` implementation. - Cleaner separation: reducers handle reduction, plugins observe via events. - Easier to add new evaluation modes - just implement `Reducer` with embedded emitter. ## Checklist - [x] Code follows conventional commit format. - [x] Branch follows naming convention (`<type>/<description>`). - [x] Tests pass (if applicable). - [ ] Documentation updated (if applicable). Reviewed-on: #32 Co-authored-by: M.V. Hutz <git@maximhutz.me> Co-committed-by: M.V. Hutz <git@maximhutz.me>
32 lines
753 B
Go
32 lines
753 B
Go
// Package "explanation" provides an observer to gather the reasoning during the
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// reduction, and present a thorough explanation to the user for each step.
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package plugins
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import (
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"fmt"
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"git.maximhutz.com/max/lambda/pkg/reducer"
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)
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// Track the reductions made by a reduction process.
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type Explanation struct {
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reducer reducer.Reducer
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}
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// Attaches a new explanation tracker to a reducer.
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func NewExplanation(r reducer.Reducer) *Explanation {
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plugin := &Explanation{reducer: r}
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r.On(reducer.StartEvent, plugin.Start)
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r.On(reducer.StepEvent, plugin.Step)
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return plugin
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}
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func (t *Explanation) Start() {
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fmt.Println(t.reducer.Expression().String())
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}
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func (t *Explanation) Step() {
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fmt.Println(" =", t.reducer.Expression().String())
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}
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