org.aya.syntax.ref.MetaVar Maven / Gradle / Ivy

Go to download
// Copyright (c) 2020-2024 Tesla (Yinsen) Zhang.
// Use of this source code is governed by the MIT license that can be found in the LICENSE.md file.
package org.aya.syntax.ref;

import kala.collection.SeqView;
import kala.collection.immutable.ImmutableSeq;
import org.aya.generic.AyaDocile;
import org.aya.pretty.doc.Doc;
import org.aya.syntax.core.term.SortTerm;
import org.aya.syntax.core.term.Term;
import org.aya.syntax.core.term.call.MetaCall;
import org.aya.util.error.SourcePos;
import org.aya.util.prettier.PrettierOptions;
import org.jetbrains.annotations.NotNull;
import org.jetbrains.annotations.Nullable;

/**
 * if the args of the {@link MetaCall} is larger than ctxSize,
 * then in case there is {@link OfType}, we will need to type check the argument
 * and check the solution against the iterated codomain instead of the type itself.
 *
 * @param ctxSize size of the original context.
 * @param pos     error report of this MetaCall will be associated with this position.
 * @see MetaCall
 */
public record MetaVar(
  @Override @NotNull String name,
  @NotNull SourcePos pos,
  int ctxSize, @NotNull Requirement req
) implements AnyVar {
  @Override public boolean equals(@Nullable Object o) { return this == o; }
  @Override public int hashCode() { return System.identityHashCode(this); }

  public @NotNull MetaCall asPiDom(@NotNull SortTerm sort, @NotNull ImmutableSeq args) {
    assert req == Misc.IsType;
    var typed = new MetaVar(name, pos, ctxSize, new PiDom(sort));
    return new MetaCall(typed, args);
  }

  public sealed interface Requirement extends AyaDocile {
    Requirement bind(SeqView vars);
  }
  public enum Misc implements Requirement {
    Whatever,
    IsType,
    ;
    @Override public @NotNull Doc toDoc(@NotNull PrettierOptions options) {
      return switch (this) {
        case Whatever -> Doc.plain("Nothing!");
        case IsType -> Doc.sep(Doc.plain("_"), Doc.symbols(":", "?"));
      };
    }
    @Override public Misc bind(SeqView vars) { return this; }
  }
  /**
   * @param type hopefully in the closed context.
   *             Upon creation, it will be bound with all the local vars.
   */
  public record OfType(@NotNull Term type) implements Requirement {
    @Override public @NotNull Doc toDoc(@NotNull PrettierOptions options) {
      return Doc.sep(Doc.symbol("?"), Doc.symbol(":"), type.toDoc(options));
    }
    @Override public OfType bind(SeqView vars) {
      return new OfType(type.bindTele(vars));
    }
  }
  /**
   * The meta variable is the domain of a pi type which is of a known type.
   */
  public record PiDom(@NotNull SortTerm sort) implements Requirement {
    @Override public PiDom bind(SeqView vars) { return this; }
    @Override public @NotNull Doc toDoc(@NotNull PrettierOptions options) {
      return Doc.sep(Doc.symbols("?", "->", "_", ":"), sort.toDoc(options));
    }
  }
}