如何在Ada中实现继承以及它是否已在GUI中构建？

问题描述

Ada是否带有内置GUI，它与Oberon具有相同的唯一继承方法吗？

Does Ada come with built-in GUI, and does it have the same unique approach to inheritance as does Oberon?

推荐答案

否，Ada没有内置GUI。但是我能想到的最接近的语言是PostScript。 （从技术上讲，Java语言没有；尽管它包含的库​​也有。）也就是说，有一个GTK绑定（我根本没有使用过）和一个OpenGL绑定（我只玩过；并且老实说，OpenGL绑定比我想要的要薄得多。）

No, Ada does not come with a built-in GUI; but then the closest language that I can think of is PostScript. (Technically, the Java-language does not; though its included library does.) That being said there is a GTK binding (which I haven't used at all) and an OpenGL binding (that I've only played with; and to be honest the OpenGL binding is far thinner a binding than I'd like).

Oberon的继承模型（据我了解）是单扩展继承，与艾达尽管Ada确实集成了类似于Java的接口系统。我尚未真正使用过Oberon，因此我无法真正为您提供这两个的并排示例，但可以向您展示Ada的示例。

Oberon's inheritance model (as I understand) is single-extension inheritance which is the same as Ada; though Ada does incorporate an Interface system similar to Java. I haven't actually used Oberon, so I can't really provide you with a side-by-side examples for the two, but can show you an example of Ada's.

Base：

Type Base is Abstract Tagged Record
   Null;
End Record; -- Base

-- Base Operations
Procedure Op( Object : In Out Base );
Procedure Dispatching_Op( Object : In Out Base'Class );

扩展名：

Type Extended is New Base With Record
  Null;
End Record; -- Extended

Overriding Procedure Op( Object : In Out Extended );

具有以下内容的正文：

  Procedure Op( Object : In Out Base ) is
  begin
     Put( "Hello" );
  end Op;

  Procedure Dispatching_Op( Object : In Out Base'Class ) is
  begin
     Op( Object );
     Put_Line( " World." );
  end Dispatching_Op;

  Procedure Op( Object : In Out Extended ) is
  begin
     Put( "Goodbye" );
  End Op;

给定类型为P的对象{P：K.Base'Class：= K.Extended' （Others =><>）;}可以这样称呼：

Which given an object of type P {P : K.Base'Class:= K.Extended'(Others => <>);} could be called like so:

P.Dispatching_Op;

在这种情况下会产生以下结果：

And would produce the following results in this instance:

Goodbye World.

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