📩 👨🏻‍🚀 🕺🏿 Cómo beneficiarse de la escritura estática 👨🏿‍🤝‍👨🏽 🙌 🐂

Los datos en vivo de tipo limitado fluyen de un estado a otro

Este artículo trata sobre cómo aprovechar al máximo el sistema de tipos estáticos al diseñar su código. El artículo intenta ser independiente del lenguaje (no siempre funciona), los ejemplos están en Java y se toman de la vida. Aunque los lenguajes académicos como Idris nos permiten hacer trucos más útiles con la escritura estática , y la inferencia de tipo completo reduce significativamente el tamaño de la ceremonia , en el trabajo escribimos en otros tipos de lenguajes y queremos poder aplicar buenos conocimientos. en la práctica, ya que mejorará nuestra vida hoy ...

Breve recuento de la trama del artículo.

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    final String name;
    final @Nullable String oldType;
    final @Nullable String newType;

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        String name, 
        @Nullable String oldType, 
        @Nullable String newType
    ) {
        this.name = name;
        this.oldType = oldType;
        this.newType = newType;
    }

    @Override
    public String toString() {
        if (oldType != null && newType != null) {
            return String.format(
                "Column %s changed the type: %s->%s",
                name,
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            );
        }
        if (oldType == null) {
            return String.format(
                "Column %s with type %s has been added", 
                name, 
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            );
        }
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        );
    }
}

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abstract class SchemaDiff {
    final String name;

    protected SchemaDiff(String name) {
        this.name = name;
    }
}

final class RemovedColumn extends SchemaDiff {
    final String type;

    RemovedColumn(String name, String type) {
        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;

    AddedColumn(String name, String type) {
        super(name);
        this.type = type;
    }

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

final class TypeChanged extends SchemaDiff {
    final String oldType;
    final String newType;

    TypeChanged(String name, String oldType, String newType) {
        super(name);
        this.oldType = oldType;
        this.newType = newType;
    }

    @Override
    public String toString() {
        return String.format(
            "Column's %s type has been changed: %s->%s", 
            name, 
            oldType, 
            newType
        );
    }
}

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Cualquier polimorfismo le permite colapsar lo mismo hasta tipos de gráficos de cálculo en un solo gráfico

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void process(List<Item> items) {
    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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    Table<T> table
) {
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    table.store(result);
    return result;
}

void process(List<Item> items) {
    List<? extends WithId> docs = isLegacy ?
        store(items, x -> toLegacy(x), legacyTable) : 
        store(items, x -> toModern(x, context), modernTable);
    logEvent(docs);
}

logEvent

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list.add(1);

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vec.push(1);

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for(long x: xs) {
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enum FeatureType {
    ELMO,
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    LIFETIME_7D,
}

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<TEntry extends FeatureEntry> Collection<TEntry> find(Collection<Id> ids, FeatureType type);

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enum FeatureType() {
    ELMO(EmbeddingEntry.class),
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    ;

    private final Class<? extends FeatureEntry> entryClass;

    public FeatureType(Class<? extends FeatureEntry> entryClass) {
        this.entryClass = entryClass;
    }

    public Class<? extends FeatureEntry> getEntryClass() {
        return entryClass;
    }
}

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final class FeatureType<TEntry extends FeatureEntry> {
    public static final FeatureType<EmbeddingEntry> ELMO = 
        new FeatureType("elmo", EmbeddingEntry.class);
    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(
   Collection<Id> ids, 
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);

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static <TLeft, TRight, TResult> 
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lift(BiFunction<TLeft, TRight, TResult> function) {
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    );
}

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    Collection<Id> ids, 
    FeatureType<TEntry> type, 
    Language language
);

<TEntry extends FeatureEntry> Collection<TEntry> find(
    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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DSL vs composability

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//   :
private BlendedTermQuery(Term[] terms, float[] boosts, TermStates[] contexts) {
    assert terms.length == boosts.length;
    assert terms.length == contexts.length;
    this.terms = terms;
    this.boosts = boosts;
    this.contexts = contexts;
    //  terms, boosts  contexts    

    
    //     :      .
    new InPlaceMergeSorter() {
      //     terms,     .
      @Override
      protected int compare(int i, int j) {
        return terms[i].compareTo(terms[j]);
      }

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     @Override
      protected void swap(int i, int j) {
        Term tmpTerm = terms[i];
        terms[i] = terms[j];
        terms[j] = tmpTerm;

        TermStates tmpContext = contexts[i];
        contexts[i] = contexts[j];
        contexts[j] = tmpContext;

        float tmpBoost = boosts[i];
        boosts[i] = boosts[j];
        boosts[j] = tmpBoost;
      }
    //   , ..  : -.
    }.sort(0, terms.length);
  }

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Foo(float[] boosts) {
    this.boosts = boosts.clone();

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      @Override
      protected int compare(int i, int j) {
        return Float.compare(boosts[i], boosts[j]);
      }

      @Override
      protected void swap(int i, int j) {
        float tmpBoost = this.boosts[i];
        this.boosts[i] = this.boosts[j];
        this.boosts[j] = tmpBoost;
      }
    }.sort(0, terms.length);
  }

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Muchas gracias a estas personas por revisar el artículo antes de su publicación:

Dmitry Yudakov
Dmitry Petrov
Nikolay Mishuk
Anastasia Pavlovskaya
Polina Romanchenko
Svetlana Yesenkova
Yan Kornev

Cómo beneficiarse de la escritura estática

Breve recuento de la trama del artículo.

C

,

DSL vs composability

P.S.

More articles: