Object-oriented topics in C and C++ (8) - a more advanced preprocessor PHP

List of articles in this column

1. What is object-oriented

2. C language can also implement object-oriented

3. Inelegant features in C++

4. Solve encapsulation and avoid interfaces

5. Reasonable use Templates to avoid code redundancy

6. C++ can also reflect

7. Singleton mode solves the construction order problem of static member objects and global objects

8. More advanced preprocessor PHP

8. More The advanced preprocessor PHP

C++ macros are very difficult to use in some cases. For example, the code is expanded like this:

Macro(A, B, C, D)

=>

func(“A ", A);
func(“B”, B);
func(“C”, C);
func(“D”, D);

test(A);
test(B);
test(C);
test(D);

This is too difficult for macros. In order to achieve complex macro expansion, we hope to use a more advanced preprocessor to implement this function.

We use PHP here to preprocess the code, and use the PHP code as a C++ macro.
Of course, you can also use Python for code generation, but since PHP is embedded, it may be more convenient to handle. Of course, other languages ​​​​can also be equipped with templates.

<code><span>/* main.php */</span>
<?php $return_m = <span>"return a + b;" ?>

<span>#include <iostream></iostream></span><span>using</span><span>namespace</span><span>std</span>;

<span>int</span> func(<span>int</span> a, <span>int</span> b) {
    <?php echo $return_m; ?> 
}
<span>int</span> main() {
    <span>cout</span> 1, <span>2</span>) return<span>0</span>;
}</code>

We use the following instructions to generate C++ code:

<code>php main.php > main.cpp
</code>

Okay, the following is the same as normal project compilation. You can even write the php command into the makefile to automatically generate

The above has introduced the object-oriented topic of C and C++ (8) - the more advanced preprocessor PHP, including aspects of it. I hope it will be helpful to friends who are interested in PHP tutorials.