First commit

.gitignore

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+/target

Cargo.lock

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+# This file is automatically @generated by Cargo.
+# It is not intended for manual editing.
+version = 3
+
+[[package]]
+name = "metrify"
+version = "0.1.0"

Cargo.toml

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+[package]
+name = "metrify"
+version = "0.1.0"
+edition = "2021"
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[dependencies]

src/conversions.rs

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+use crate::units::{Metric, MetricQuantity, NonMetric, NonMetricQuantity};
+
+struct Conversion {
+	from: f64,
+	to: MetricQuantity,
+}
+
+fn get_conversion(unit: NonMetric) -> Conversion {
+	match unit {
+		// Length
+		NonMetric::Foot => Conversion {
+			from: 10_000.0,
+			to: MetricQuantity { amount: 3048.0, unit: Metric::Metre },
+		},
+		NonMetric::Inch => Conversion {
+			from: 10_000.0,
+			to: MetricQuantity { amount: 254.0, unit: Metric::Metre },
+		},
+		NonMetric::Yard => Conversion {
+			from: 10_000.0,
+			to: MetricQuantity { amount: 9144.0, unit: Metric::Metre },
+		},
+		NonMetric::Mile => Conversion {
+			from: 1_000.0,
+			to: MetricQuantity { amount: 1609344.0, unit: Metric::Metre },
+		},
+		// Weight
+		NonMetric::Ounce => Conversion {
+			from: 1_000_000_000.0,
+			to: MetricQuantity { amount: 28349523125.0, unit: Metric::Gram },
+		},
+		NonMetric::Pound => Conversion {
+			from: 100_000.0,
+			to: MetricQuantity { amount: 45359237.0, unit: Metric::Gram },
+		},
+		NonMetric::Stone => Conversion {
+			from: 100_000.0,
+			to: MetricQuantity { amount: 635029318.0, unit: Metric::Gram },
+		},
+	}
+}
+
+pub fn convert(from: NonMetricQuantity) -> MetricQuantity {
+	let conversion = get_conversion(from.unit);
+	let amount = from.amount * conversion.to.amount / conversion.from;
+	let unit = conversion.to.unit;
+	MetricQuantity { amount, unit }
+}
+
+#[cfg(test)]
+mod test {
+	use super::*;
+
+	struct Test(NonMetric, f64);
+
+	fn run_tests(tests: &[Test], unit: Metric) {
+		for test in tests {
+			let from = NonMetricQuantity {
+				amount: 1.0,
+				unit: test.0,
+			};
+			let to = MetricQuantity {
+				amount: test.1,
+				unit: unit,
+			};
+			assert_eq!(convert(from), to);
+		}
+	}
+
+	#[test]
+	fn length() {
+		let tests = [
+			Test(NonMetric::Inch, 0.0254),
+			Test(NonMetric::Foot, 0.3048),
+			Test(NonMetric::Yard, 0.9144),
+			Test(NonMetric::Mile, 1609.344),
+		];
+		run_tests(&tests, Metric::Metre);
+	}
+
+	#[test]
+	fn weight() {
+		let tests = [
+			Test(NonMetric::Ounce, 28.349523125),
+			Test(NonMetric::Pound, 453.59237),
+			Test(NonMetric::Stone, 6350.29318),
+		];
+		run_tests(&tests, Metric::Gram);
+	}
+}

src/lib.rs

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+mod units;
+mod conversions;
+
+pub use units::{NonMetric, NonMetricQuantity};
+
+pub use conversions::convert;

src/main.rs

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+use metrify::{NonMetric, NonMetricQuantity};
+use metrify::convert;
+
+fn main() {
+	let quantity = NonMetricQuantity { amount: 6.0, unit: NonMetric::Foot };
+	dbg!(convert(quantity));
+}

src/units.rs

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+#[derive(Clone, Copy, Debug, PartialEq)]
+pub enum Metric {
+	Metre,
+	Gram,
+}
+
+#[derive(Clone, Copy, Debug, PartialEq)]
+pub enum NonMetric {
+	// Length
+	Foot,
+	Inch,
+	Mile,
+	Yard,
+	// Weight
+	Ounce,
+	Pound,
+	Stone,
+}
+
+#[derive(Debug, PartialEq)]
+pub struct MetricQuantity {
+	pub amount: f64,
+	pub unit: Metric,
+}
+
+#[derive(Debug, PartialEq)]
+pub struct NonMetricQuantity {
+	pub amount: f64,
+	pub unit: NonMetric,
+}