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%install '.package(path: "$cwd/FastaiNotebook_08_data_block")' FastaiNotebook_08_data_block

Installing packages:
	.package(path: "/home/ubuntu/fastai_docs/dev_swift/FastaiNotebook_08_data_block")
		FastaiNotebook_08_data_block
With SwiftPM flags: []
Working in: /tmp/tmpd4g5mfxf
Fetching https://github.com/mxcl/Path.swift
Fetching https://github.com/JustHTTP/Just
Completed resolution in 3.88s
Cloning https://github.com/mxcl/Path.swift
Resolving https://github.com/mxcl/Path.swift at 0.16.2
Cloning https://github.com/JustHTTP/Just
Resolving https://github.com/JustHTTP/Just at 0.7.1
Compile Swift Module 'Just' (1 sources)
Compile Swift Module 'Path' (9 sources)
Compile Swift Module 'FastaiNotebook_08_data_block' (13 sources)
Compile Swift Module 'jupyterInstalledPackages' (1 sources)
Linking ./.build/x86_64-unknown-linux/debug/libjupyterInstalledPackages.so
Initializing Swift...
Loading library...
Installation complete!

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// export

public protocol HetDictKey: Hashable {
    associatedtype ValueType
    static var defaultValue: ValueType { get }
}

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// export

public struct HeterogeneousDictionary {
    private var underlying: [AnyHashable : Any] = [:]
    
    public init() {}
    public init<T: HetDictKey>(_ key: T, _ value: T.ValueType) {
        self.underlying = [key: value]
    }
    public init<T1: HetDictKey, T2: HetDictKey>(_ key1: T1, _ value1: T1.ValueType, _ key2: T2, _ value2: T2.ValueType) {
        self.underlying = [key1: value1, key2: value2]
    }

    public subscript<T: HetDictKey>(key: T) -> T.ValueType {
        get {
            return underlying[key] as! T.ValueType? ?? T.defaultValue
        }
        set(newValue) {
            underlying[key] = newValue as Any
        }
    }
    
    public mutating func merge(_ other: HeterogeneousDictionary,
        uniquingKeysWith combine: (Any, Any) throws -> Any) rethrows {
        try self.underlying.merge(other.underlying, uniquingKeysWith: combine)
    }
}

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// export

// Common keys
public struct Accuracy: HetDictKey, Equatable {
    public init() {}
    public static var defaultValue: Float = 0
}

public struct LearningRate: HetDictKey, Equatable {
    public init() {}
    public static var defaultValue: Float = 0.4
}

public struct StepCount: HetDictKey, Equatable {
    public init() {}
    public static var defaultValue = 0
}

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// Sample usage
var m = HeterogeneousDictionary()

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print(m[LearningRate()])
m[LearningRate()] = 3.4
print(m[LearningRate()])

print(m[StepCount()])
m[StepCount()] = 3
print(m[StepCount()])

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print(type(of: m[StepCount()]))
print(type(of: m[LearningRate()]))

Int
Float

Note: for performance, need to optimize hashcode to avoid collisions.

Export¶

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import Path
import FastaiNotebook_08_data_block

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notebookToScript(fname: (Path.cwd / "08a_heterogeneous_dictionary.ipynb").string)

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