我想实例化一个包并将传递给它的函数传递给重载运算符，以生成通用二进制搜索树。这是规格。
bstgen.ads（摘要）
with Ada.Text_IO; use Ada.Text_IO;
with Ada.Unchecked_Deallocation;
GENERIC
type Akey is private;
type TreeRecord is private;
with function "<"(K: in Akey; R: in TreeRecord) return Boolean;
with function ">"(K: in Akey; R: in TreeRecord) return Boolean;
with function "="(K: in Akey; R: in TreeRecord) return Boolean;
PACKAGE BSTGen IS
TYPE St10 IS NEW String(1..10);
TYPE TreePt IS PRIVATE;
PACKAGE EnumIO IS NEW Ada.Text_IO.Enumeration_IO(Akey); USE EnumIO;
driver.adb（摘要）
with Ada.Text_IO; use Ada.Text_IO;
WITH BSTGen;
PROCEDURE Driver IS
IP: Integer := 1;
TYPE Names IS (Resig,Keene,Marsden,Vuijic,Marcus,Gonzalez);
PACKAGE NamesIO IS NEW Ada.Text_IO.Enumeration_IO(Names);
type St10 is NEW String(1..10);
type Customer is
record Name: Names;
PhoneNumber: St10;
end record;
function "<"(K: in Names; R: in Customer) return Boolean is begin
return K < R.Name;
end "<";
function ">"(K: in Names; R: in Customer) return Boolean is begin
return K > R.Name;
end ">";
function "="(K: in Names; R: in Customer) return Boolean is begin
return K = R.Name;
end "=";
PACKAGE IntIO IS NEW Ada.Text_IO.Integer_IO(Integer); USE IntIO;
PACKAGE mybst is NEW BSTGen(Names,Customer,<,>,=); USE mybst;
R, Pt: TreePt;
Name: Names;
Phone: St10;
Status: Boolean;
BEGIN
R := CreateTree;
Pt := R;
但是，当我尝试编译时，这是输出：
driver.adb:24:04: expect subprogram or entry name in instantiation of "<"
driver.adb:24:04: instantiation abandoned
bstgen.ads:19:53: expect discrete type in instantiation of "Enum"
bstgen.ads:19:53: instantiation abandoned
这包括一堆错误，指出driver.adb的方法不可见，这是可以预期的，因为放弃了mybst的实例化。我该如何解决？
最佳答案
在bstgen.ads中，您说
PACKAGE EnumIO IS NEW Ada.Text_IO.Enumeration_IO(Akey);
但在通用正式部分中，您说
type Akey is private;
这意味着除了可以使用相等和赋值之外，编译器对实际类型的假设很少。它可能是数百个字节的记录；它当然不必是枚举。
为了确保
Akey是一个枚举，您需要说type Akey is (<>);
如ARM12.5(13)中所示。
在
driver.adb中，您说PACKAGE mybst is NEW BSTGen(Names,Customer,<,>,=);
应该读
PACKAGE mybst is NEW BSTGen(Names,Customer,”<“,”>”,”=“);