fn main()

in serde-generate/src/generate.rs [102:194]
88 lines of code
5 McCabe index (conditional complexity)

fn main() {
    let options = Options::from_args();
    let serde_package_name_opt = options.serde_package_name.clone();
    let named_registry_opt = match &options.input {
        None => None,
        Some(input) => {
            let name = options.module_name.clone().unwrap_or_else(|| {
                input
                    .file_stem()
                    .expect("failed to deduce module name from input path")
                    .to_string_lossy()
                    .into_owned()
            });
            let content = std::fs::read_to_string(input).expect("input file must be readable");
            let registry = serde_yaml::from_str::<Registry>(content.as_str()).unwrap();
            Some((registry, name))
        }
    };
    let runtimes: std::collections::BTreeSet<_> = options.with_runtimes.into_iter().collect();

    match options.target_source_dir {
        None => {
            if let Some((registry, name)) = named_registry_opt {
                let config = get_codegen_config(name, &runtimes, options.use_c_style_enums);

                let stdout = std::io::stdout();
                let mut out = stdout.lock();
                match options.language {
                    Language::Python3 => python3::CodeGenerator::new(&config)
                        .with_serde_package_name(serde_package_name_opt)
                        .output(&mut out, &registry)
                        .unwrap(),
                    Language::Rust => rust::CodeGenerator::new(&config)
                        .output(&mut out, &registry)
                        .unwrap(),
                    Language::Cpp => cpp::CodeGenerator::new(&config)
                        .output(&mut out, &registry)
                        .unwrap(),
                    Language::Go => golang::CodeGenerator::new(&config)
                        .output(&mut out, &registry)
                        .unwrap(),
                    Language::Java => {
                        panic!("Code generation in Java requires `--target-source-dir`")
                    }
                    Language::Dart => {
                        panic!("Code generation in Dart requires `--target-source-dir`")
                    }
                    Language::TypeScript => typescript::CodeGenerator::new(&config)
                        .output(&mut out, &registry)
                        .unwrap(),
                    Language::CSharp => {
                        panic!("Code generation in C# requires `--target-source-dir`")
                    }
                    Language::Swift => swift::CodeGenerator::new(&config)
                        .output(&mut out, &registry)
                        .unwrap(),
                }
            }
        }

        Some(install_dir) => {
            let installer: Box<dyn SourceInstaller<Error = Box<dyn std::error::Error>>> =
                match options.language {
                    Language::Python3 => {
                        Box::new(python3::Installer::new(install_dir, serde_package_name_opt))
                    }
                    Language::Rust => Box::new(rust::Installer::new(install_dir)),
                    Language::Cpp => Box::new(cpp::Installer::new(install_dir)),
                    Language::Java => Box::new(java::Installer::new(install_dir)),
                    Language::Go => {
                        Box::new(golang::Installer::new(install_dir, serde_package_name_opt))
                    }
                    Language::Dart => Box::new(dart::Installer::new(install_dir)),
                    Language::TypeScript => Box::new(typescript::Installer::new(install_dir)),
                    Language::CSharp => Box::new(csharp::Installer::new(install_dir)),
                    Language::Swift => Box::new(swift::Installer::new(install_dir)),
                };

            if let Some((registry, name)) = named_registry_opt {
                let config = get_codegen_config(name, &runtimes, options.use_c_style_enums);
                installer.install_module(&config, &registry).unwrap();
            }

            for runtime in runtimes {
                match runtime {
                    Runtime::Serde => installer.install_serde_runtime().unwrap(),
                    Runtime::Bincode => installer.install_bincode_runtime().unwrap(),
                    Runtime::Bcs => installer.install_bcs_runtime().unwrap(),
                }
            }
        }
    }
}