Rust Programming Cookbook

How to do it...

Code generation can be as easy as these few steps:

1. Run cargo new code-generation --lib in Terminal (or PowerShell on Windows) and open the directory with Visual Studio Code.
2. Open src/lib.rs and add the first simple macro:

// Repeat the statement that was passed in n timesmacro_rules! n_times {    // `()` indicates that the macro takes no argument.    ($n: expr, $f: block) => {        for _ in 0..$n {            $f()        }    }}

3. Let's do another one, this time a bit more generative. Add this outside of the testing module (for example, underneath the previous macro):

// Declare a function in a macro!macro_rules! make_fn {    ($i: ident, $body: block) => {        fn $i () $body    } }

4. Both of those macros are also very straightforward to use. Let's replace the tests ...