Ada:包装概念 [英] Ada: packaging concepts

问题描述

这是我之前的帖子的后续内容:

This is a follow up of my earlier post here:

Ada:了解私有类型并了解包装

Rectangular类型的实现是使用一个实现实现的，即，Rectangular_Method_1，并且此实现需要规范文件和主体文件.

An implementation for the Rectangular type was made using one implementation i.e. Rectangular_Method_1 and a specification file and a body file were required for this implementation.

如果我们想为用户提供另一个实现Rectangular_Method_2，则可以将主文件rectangular_Form.ads更改为

If we want to have another implementation Rectangular_Method_2 available to the user then the main file rectangular_Form.ads can be changed to

-- with Rectangular_Method_1;
-- package Rectangular_Form renames Rectangular_Method_1;
with Rectangular_Method_2;
package Rectangular_Form renames Rectangular_Method_2;

问题

1. 这是软件工程中允许另一种实现的正确方法吗，因为对于不同的实现，测试文件test_rectangular_form.adb保持相同?

如果我们创建第二个实现Rectangular_Method_2，除了该新实现的强制性新主体之外，是否需要创建单独的规范文件?但是，在新的实现中需要为Vector_Basis_r，Set_Horz，Get_Horz等提供相同的过程/功能，以便我们可以在test_rectangular_form.adb中对其进行调用.

If we create a second implementation Rectangular_Method_2, Is there a need to create a separate specification file in addition to the compulsory new body for this new implementation? There is the need however to provide the same procedures/functions for Vector_Basis_r, Set_Horz, Get_Horz etc in the new implementation so that we can call them in test_rectangular_form.adb.

谢谢...

推荐答案

如果使用GNAT，则可以将GPR文件用于项目.您可以在其中更改特定软件包的文件名，例如:

If you use GNAT, you can use GPR files for the project. In there you can change the filename for specific packages, for example:

for Specification (Rectangular_Form) use "Rectangular_Method_1.ads";
for Implementation (Rectangular_Form) use "Rectangular_Method_1.adb";

您甚至可以根据环境变量进行设置.

you can even set this depending on an environment variable.

如果规格文件的外观都相同，则可以使用Rectangular_Form.ads，并且只能使用上方的实施"行.

If your spec files all should look the same, you can use a Rectangular_Form.ads and only use the Implementation line from above.

示例GPR文件可能如下所示:

An example GPR file could look like this:

project Example is

   type Methods is ("normal", "something_else");
   Method : Methods := external ("METHOD", "normal");

   package Naming is
      case Method is
         when "normal" =>
            for Implementation ("Example") use "example_normal.adb";
         when "something_else" =>
            for Implementation ("Example") use "example_something.adb";
      end case;
   end Naming;

end Example;

然后，您可以根据您的METHOD变量使用gnatmake -P example.gpr对其进行编译，或者对gnatmake使用-XMETHOD=...参数，或者仅使用提供的默认值.

Then, you can use gnatmake -P example.gpr to compile it depending on your METHOD variable, or using a -XMETHOD=... parameter for gnatmake or just use the provided default value.

example_*.adb都应包含软件包Example的主体，而不是Example_Normal等.

The example_*.adb should all contain the body of the package Example, not Example_Normal, etc..

这篇关于Ada:包装概念的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！