generate the doc with clap_mangen

Cargo.toml

@@ -20,6 +20,7 @@ base64 = "0.21.7"
 clap = { version = "4.4.18", features = ["derive", "env", "wrap_help"] }
 clap-markdown = "0.1.3"
 clap-verbosity-flag = "2.1.2"
+clap_mangen = "0.2.18"
 log = "0.4.20"
 ocli = "0.1.1"
 serde_yaml = "0.9.31"
@@ -28,6 +29,12 @@ tempfile = "3.9.0"
 thiserror = "1.0.56"
 treediff = { git = "https://github.com/glehmann/treediff-rs.git", branch = "serde-yaml-09", features = ["with-serde-yaml"] }
 
+[build-dependencies]
+clap = { version = "4.4.18", features = ["derive", "env", "wrap_help"] }
+clap-markdown = "0.1.3"
+clap-verbosity-flag = "2.1.2"
+clap_mangen = "0.2.18"
+
 [profile.release]
 strip = "symbols"
 opt-level = "z"

build.rs

@@ -0,0 +1,24 @@
+include!("src/cli.rs");
+
+fn main() -> std::io::Result<()> {
+    generate_man::<Cli>()?;
+    Ok(())
+}
+
+fn generate_man<C: clap::CommandFactory>() -> std::io::Result<()> {
+    let command = C::command();
+    let out_dir =
+        std::path::PathBuf::from(std::env::var_os("OUT_DIR").ok_or(std::io::ErrorKind::NotFound)?);
+    let name = command.get_name();
+    let name = if name == "yage" {
+        "yage.1".to_owned()
+    } else {
+        format!("yage-{}.1", command.get_name())
+    };
+    let fname = out_dir.join(name);
+    let man = clap_mangen::Man::new(command);
+    let mut buffer: Vec<u8> = Default::default();
+    man.render(&mut buffer)?;
+    std::fs::write(fname, buffer)?;
+    Ok(())
+}