Nice/src/nice/tools/typing Types.java,NONE,1.1

Update of /cvsroot/nice/Nice/src/nice/tools/typing
In directory 
sc8-pr-cvs1.sourceforge.net:/tmp/cvs-serv27227/src/nice/tools/typing

Added Files:
        Types.java 
Log Message:
Separated high-level type operations (in nice.tools.typing.Types) from
the ones related to code generation (in nice.tools.code.Types).


--- NEW FILE: Types.java ---
/**************************************************************************/
/*                                N I C E                                 */
/*             A high-level object-oriented research language             */
/*                        (c) Daniel Bonniot 2004                         */
/*                                                                        */
/*  This program is free software; you can redistribute it and/or modify  */
/*  it under the terms of the GNU General Public License as published by  */
/*  the Free Software Foundation; either version 2 of the License, or     */
/*  (at your option) any later version.                                   */
/*                                                                        */
/**************************************************************************/

package nice.tools.typing;

/**
   Utilities for Nice types.

   @author Daniel Bonniot (bonniots@xxxxxxxxxxxx)
 */

import mlsub.typing.*;
import bossa.syntax.PrimitiveType;

public final class Types
{
  /****************************************************************
   * Predicates
   ****************************************************************/

  public static boolean isVoid(mlsub.typing.Monotype m)
  {
    return equivalent(m).head() == PrimitiveType.voidTC;
  }

  public static boolean isVoid(mlsub.typing.Polytype t)
  {
    return isVoid(t.getMonotype());
  }

  public static boolean isPrimitive(TypeConstructor tc)
  {
    return nice.tools.code.Types.javaType(tc) instanceof gnu.bytecode.PrimType;
  }

  public static boolean isPrimitive(Polytype t)
  {
    return nice.tools.code.Types.javaType(t) instanceof gnu.bytecode.PrimType;
  }

  public static boolean isMaybe(Monotype m)
  {
    // This is prob. laxist, since getTC() might be different but equivalent to 
maybeTC (?)
    return (m instanceof MonotypeConstructor)
      && ((MonotypeConstructor) m).getTC() == PrimitiveType.maybeTC;
  }

  public static boolean isSure(Monotype m)
  {
    // see comment by isMaybe (e?)
    return (m instanceof MonotypeConstructor)
      && ((MonotypeConstructor) m).getTC() == PrimitiveType.sureTC;
  }

  /****************************************************************
   * Handling of option types
   ****************************************************************/

  public static Monotype equivalent(Monotype m)
  {
    return rawType(m).equivalent();
  }

  public static void setMarkedKind(Monotype m)
  {
    m.setKind(NullnessKind.instance);
  }

  public static void makeMarkedType(MonotypeVar m)
  {
    m.setPersistentKind(NullnessKind.instance);
  }

  /** return the type with nullness markers removed */
  public static Monotype rawType(Monotype m)
  {
    m = m.equivalent();
    if (!(m instanceof MonotypeConstructor))
      {
        // It is probably a bug if this happens
        //Internal.warning("Not kinded monotype: " + m);
        return m;
      }
    else
      return ((MonotypeConstructor) m).getTP()[0];
  }

  /** return the type with nullness markers removed */
  public static Monotype rawType(MonotypeConstructor mc)
  {
    return mc.getTP()[0];
  }

  /****************************************************************
   * Functional types
   ****************************************************************/

  /** @return the domain of a functional monotype with nullness marker */
  public static Monotype[] parameters(Monotype type)
  {
    return rawType(type).domain();
  }

  /** @return the domain of a functional polytype with nullness marker */
  public static Monotype[] parameters(Polytype type)
  {
    return rawType(type.getMonotype()).domain();
  }

  /** @return the codomain of a functional polytype with nullness marker */
  public static Monotype result(Polytype type)
  {
    return ((FunType) rawType(type.getMonotype())).codomain();
  }

  /** @return the <code>rank</code>th type parameter of this type, or null. */
  public static Monotype getTypeParameter(Polytype type, int rank)
  {
    // This can only help
    type.simplify();

    return getTypeParameter(type.getMonotype(), rank);
  }

  /** 
      Transforms \forall T:K.U into \forall T:K.sure<U>
  */
  public static Polytype addSure(Polytype type)
  {
    return new Polytype
      (type.getConstraint(), 
       bossa.syntax.Monotype.sure(type.getMonotype()));
  }

  /****************************************************************
   * Type parameters
   ****************************************************************/

  /** @return the <code>rank</code>th type parameter of this type, or null. */
  public static Monotype getTypeParameter(Monotype type, int rank)
  {
    // get rid of the nullness part
    type = rawType(type);

    if (! (type instanceof MonotypeConstructor))
      return null;

    Monotype[] parameters = ((MonotypeConstructor) type).getTP();

    if (parameters.length <= rank)
      return null;
    else
      return parameters[rank];
  }

  /****************************************************************
   * Domains
   ****************************************************************/

  public static Domain domain(Polytype t)
  {
    // remove nullness marker
    Monotype[] m = parameters(t.getMonotype());

    return new Domain(t.getConstraint(), new TupleType(m));
  }
}



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