M.V. Hutz
eba2182151
Introduce pkg/expr.Expression as a base interface for all evaluatable expression types, enabling future support for multiple evaluation modes (SKI combinators, typed lambda calculus, etc.). - Add pkg/expr/expr.go with Expression interface requiring String() method. - Update lambda.Expression to embed expr.Expression. - Add String() method to Abstraction, Application, and Variable types. - Update plugins to use String() instead of lambda.Stringify().
32 lines
779 B
Go
32 lines
779 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/internal/engine"
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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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process *engine.Engine
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}
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// Attaches a new explanation tracker to a process.
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func NewExplanation(process *engine.Engine) *Explanation {
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plugin := &Explanation{process: process}
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process.On(engine.StartEvent, plugin.Start)
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process.On(engine.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.process.Expression).String())
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}
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func (t *Explanation) Step() {
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fmt.Println(" =", (*t.process.Expression).String())
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}
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