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c153aba61e
- MetaphorFree.cs: guard -> SomeDependency.mightThrowWhenPreconditionNotSatisfied(a) -> tail, capture-to-parameter story for the deck - WeatherStation.cs: SprinklerController, LightSensor.Read() byte -> SunExposure, tail branches - IceCreamShop.cs: third repetition, Thermometer byte -> Warmth, tail branches
80 lines
2.4 KiB
C#
80 lines
2.4 KiB
C#
// Example 3 — Ice cream shop demo of Slice with Lambda (C#)
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//
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// Condensed mechanics: https://sammancoaching.org/refactorings/slice.html
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// (where that page says mock, we use a lambda instead).
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//
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// Third repetition, same complexity as ScheduleWatering in WeatherStation.cs
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// (guard -> one dependency call -> map to enum -> constant tail), so
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// participants can practice extracting a lambda a second time. The C#
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// delegate syntax is worth the repetition:
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//
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// Func<byte> readTemperature = () => _thermometer.Read();
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//
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// Cast:
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// Thermometer — hardware-ish dependency. Read() returns a raw
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// byte value (not calibrated, the client decides
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// what it means).
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// Warmth — enum. Reading > 25 => Warm, otherwise Cold.
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// (Sunny/Shady's cousin from WeatherStation.cs.)
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// ThawAmount — enum. None / Medium / Low.
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// IceCreamShop — the client. Owns the _thawedToday flag, so the
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// guard is about client state, not sensor state.
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using System;
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public enum Warmth
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{
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Cold,
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Warm
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}
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public enum ThawAmount
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{
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None,
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Medium,
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Low
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}
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public class Thermometer
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{
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private readonly Random _rng = new Random(); // stand-in for the hardware
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public byte Read()
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{
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return (byte)_rng.Next(50); // raw sensor value
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}
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}
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public class IceCreamShop
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{
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private readonly Thermometer _thermometer;
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private bool _thawedToday; // event-style client state
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public IceCreamShop(Thermometer thermometer)
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{
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_thermometer = thermometer;
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}
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public ThawAmount ThawStock()
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{
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if (_thawedToday) // guard: client state, stays
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{
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return ThawAmount.None;
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}
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_thawedToday = true; // set only after thawing
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byte temperature = _thermometer.Read(); // middle: unwanted dependency
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Warmth warmth = ToWarmth(temperature);
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if (warmth == Warmth.Warm) // tail: complex behaviour below
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{ // the extraction point
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return ThawAmount.Medium;
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}
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return ThawAmount.Low;
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}
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private static Warmth ToWarmth(byte temperature)
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{
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return temperature > 25 ? Warmth.Warm : Warmth.Cold;
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}
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}
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