👨‍🚒 🎺 🛰️ 静的型付けの恩恵を受ける方法 ➰ 👩🏼‍🔬 🏨

この記事では、コードを設計するときに静的型システムを最大限に活用する方法について説明します。この記事は言語にとらわれないように努めており（常に機能するとは限りません）、例はJavaであり、実際から引用されています。Idrisのような学術言語では、静的型付けでより便利なトリックを実行でき、完全な型推論によって式典のサイズが大幅に削減されますが、職場では他の種類の言語で記述しているため、十分な知識を応用できるようにしたいと考えています。実際には、それが今日の私たちの生活をより良くするので...

記事の筋書きの簡単な説明

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    ) {
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abstract class SchemaDiff {
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}

final class RemovedColumn extends SchemaDiff {
    final String type;

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        super(name);
        this.type = type;
    }

    @Override
    public String toString() {
        return String.format(
            "Column %s with type %s has been removed", 
            name, 
            type
        );
    }
}

final class AddedColumn extends SchemaDiff {
    final String type;

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        super(name);
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    }

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}

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    final String oldType;
    final String newType;

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    }

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    if (isLegacy) {
        List<Legacy> docs = items.stream()
            .map(x -> toLegacy(x))
            .collect(toList);
        legacyTable.store(docs);
        logEvent(docs.stream().map(x->x.getId()).collect(toList()));
    } else {
        List<Modern> docs = items.stream()
            .map(x->toModern(x, context))
            .collect(toList);
        modernTable.store(docs);
        logEvent(docs.stream().map(x->x.getId()).collect(toList()));
    }
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void process(List<Item> items) {
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    logEvent(docs);
}

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enum FeatureType {
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}

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    ;

    private final Class<? extends FeatureEntry> entryClass;

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    }

    public Class<? extends FeatureEntry> getEntryClass() {
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final class FeatureType<TEntry extends FeatureEntry> {
    public static final FeatureType<EmbeddingEntry> ELMO = 
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    public static final FeatureType<BlacklistEntry> SLANG = 
        new FeatureType("slang", BlacklistEntry.class);
    public static final FeatureType<FloatEntry> LIFETIME_7D = 
        new FeatureType("lifetime_7d", FloatEntry.class);

    private final Class<TEntry> entryClass;
    private final String name;
    private FeatureType(String name, Class<TEntry> entryClass) {
        this.name = name;
        this.entryClass = entryClass;
    }

    public String getName() {
        return name;
    }

    public Class<TEntry> getEntryClass() {
        return entryClass;
    }
}

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<TEntry extends FeatureEntry> Collection<TEntry> find(
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);

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);

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    Collection<Id> ids, 
    FeatureType<TEntry> type, 
    Country country
);

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class FeatureType<TEntry extends FeatureEntry> {
    public static final ByLanguage<EmbeddingEntry> ELMO =
        new ByLanguage<>("elmo", EmbeddingEntry.class);
    public static final ByCountry<BlacklistEntry> SLANG = 
        new ByCountry<>("slang", BlacklistEntry.class);
    public static final ByCountry<FloatEntry> LIFETIME_7D = 
        new ByCountry<>("lifetime_7d", FloatEntry.class);

    private final Class<TEntry> entryClass;
    private final String name;
    private FeatureType(String name, Class<TEntry> entryClass) {
        this.name = name;
        this.entryClass = entryClass;
    }

    public String getName() {
        return name;
    }

    static final class ByLanguage<TEntry extends FeatureEntry>
        extends FeatureType<TEntry> {...}
    static final class ByCountry<TEntry extends FeatureEntry> 
        extends FeatureType<TEntry> {...}
}

API :

<TEntry extends FeatureEntry> Collection<TEntry> find(
    Collection<Id> ids, 
    FeatureType.ByLanguage<TEntry> type, 
    Language language
);

<TEntry extends FeatureEntry> Collection<TEntry> find(
    Collection<Id> ids, 
    FeatureType.ByCountry<TEntry> type, 
    Country country
);

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    this.terms = terms;
    this.boosts = boosts;
    this.contexts = contexts;
    //  terms, boosts  contexts    

    
    //     :      .
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    }.sort(0, terms.length);
  }

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      }

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        this.boosts[i] = this.boosts[j];
        this.boosts[j] = tmpBoost;
      }
    }.sort(0, terms.length);
  }

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公開前に記事をレビューしてくれたこれらの人々に感謝します。

ドミトリー・ユダコフ
ドミトリー・ペトロフ
ニコライ・ミシュク
アナスタシアパブロフスカヤ
ポリーナロマンチェンコ
スヴェトラーナ・イェセンコヴァ
ヤン・コルネフ

静的型付けの恩恵を受ける方法

記事の筋書きの簡単な説明

C

,

DSL vs composability

P.S.

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