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77ae05c28c
The refactoring is now published as Slice on sammancoaching.org: https://sammancoaching.org/refactorings/slice.html - git mv ideas/split-loop-with-lambda -> ideas/slice-with-lambda - rename learning-hour file and update frontmatter name - update paths in tools/rehearse scripts and report title - update prose: 'Split Loop with Lambda' -> 'Slice with Lambda' in learning hour, exercise READMEs, storyboard, solution comments - link the published Slice refactoring from the pattern draft
72 lines
2.1 KiB
C#
72 lines
2.1 KiB
C#
// Example 2 — Weather Station domain 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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// Cast (Head First Design Patterns Weather Station, reduced):
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// LightSensor — hardware-ish dependency. Read() returns a byte.
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// SunExposure — enum. Reading > 128 => Sunny, otherwise Shady.
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// WateringDuration — enum. None / Medium / Short.
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// (Long is YAGNI until the for-loop version of this
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// exercise exists.)
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// SprinklerController — the client. Owns the _wateredToday 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 SunExposure
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{
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Shady,
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Sunny
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}
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public enum WateringDuration
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{
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None,
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Medium,
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Short
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}
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public class LightSensor
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{
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private readonly Random _rng = new Random(); // stand-in for hardware noise
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public byte Read()
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{
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return (byte)_rng.Next(256);
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}
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}
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public class SprinklerController
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{
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private readonly LightSensor _lightSensor;
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private bool _wateredToday; // event-style client state
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public SprinklerController(LightSensor lightSensor)
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{
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_lightSensor = lightSensor;
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}
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public WateringDuration ScheduleWatering()
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{
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if (_wateredToday) // guard: client state, stays
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{
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return WateringDuration.None;
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}
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_wateredToday = true; // set only after watering
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byte reading = _lightSensor.Read(); // middle: unwanted dependency
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SunExposure exposure = ToSunExposure(reading);
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if (exposure == SunExposure.Sunny) // tail: complex behaviour below
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{ // the extraction point
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return WateringDuration.Medium;
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}
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return WateringDuration.Short;
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}
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private static SunExposure ToSunExposure(byte reading)
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{
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return reading > 128 ? SunExposure.Sunny : SunExposure.Shady;
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}
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}
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