type.h

一个面向对像语言的编译器

/*
 * File: type.h
 * -------------
 * Objects of the Type class are used to store and compare type
 * information for variables, functions, and classes.
 */

#ifndef _H_type
#define _H_type

#include <stdlib.h>
#include "decllist.h"
class Scope;
class Declaration; 


class Type {

  public:
                  // These are the four kinds of Types we will be dealing with
    typedef enum { Base, Array, Class, Function } KindOfType;
   
  private:
    KindOfType typeCode;
    char *typeName;
    union {             // need different fields for diff kinds, so use union
      struct { Type *elemType;    } arrayType;    
      struct { char *name;
               Scope *fields;
               Type *superclass;  } classType; 
      struct { Type *returnType;
               DeclList *formals; } fnType;   
    } info;
 
  public:
               // public constants for the base Type objects for built-ins
    static Type *intType, *doubleType, *boolType, *voidType,
                *nullType, *stringType, *errorType;

              // ctor for new types
    Type(KindOfType kind, const char *nameForType);

              // Intended to be used for printing the type in error messages
    const char *ToString()          { return typeName; }

              // some trivial predicate accessors

    bool IsBaseType()              { return typeCode == Base; }
    bool IsArrayType()             { return typeCode == Array; }
    bool IsClassType()             { return typeCode == Class; }
    bool IsFunctionType()          { return typeCode == Function; }

    bool IsEquivalentTo(Type *other);

                // Operations specific to ArrayType objects
    static Type *NewArrayType(Type *elemType);
    Type *GetArrayElemType();

               // Operations specific to ClassType objects
    static Type *NewClassType(const char *name, Type *super);
    const char *GetClassName();
    Scope *GetClassScope();

              // Operations specific to FunctionType objects
    static Type *NewFunctionType(Type *returnType, DeclList *formals);
    Type *GetFnReturnType();
    DeclList *GetFnFormals();
};

#endif