Add compile time completion generation

packages/perseus-cli/Cargo.toml

@@ -56,6 +56,11 @@ walkdir = "2"
 openssl = { version = "0.10.52", optional = true}
 brotlic = "0.8"
 
+[build-dependencies]
+clap = { version = "4.2", features = ["color", "derive"], optional = true }
+clap_complete = { version = "4.5.7", optional = true }
+clap_complete_nushell = { version = "4.5.2", optional = true }
+
 [dev-dependencies]
 assert_cmd = "2"
 assert_fs = "1"
@@ -70,5 +75,7 @@ name = "perseus"
 path = "src/bin/main.rs"
 
 [features]
+default = ["completions"]
+completions = ["clap", "clap_complete", "clap_complete_nushell"]
 # `reqwest` uses the system-native transport layer by default, this is necessary in some environments
 vendored-openssl = [ "openssl/vendored" ]

packages/perseus-cli/build.rs

@@ -0,0 +1,33 @@
+#[cfg(feature = "completions")]
+mod completions {
+    #[path = "../src/parse.rs"]
+    mod parse;
+
+    use clap::{CommandFactory, ValueEnum};
+    use clap_complete::{generate_to, shells::Shell};
+    use clap_complete_nushell::Nushell;
+    use std::io::Error;
+
+    pub fn generate_completions() -> Result<(), Error> {
+        let out_dir = "completions";
+        let bin_name = "perseus";
+        // on windows, bin_name is "perseus.exe"
+        #[cfg(windows)]
+        let bin_name = "perseus.exe";
+
+        let mut cmd = parse::Opts::command();
+
+        for shell in Shell::value_variants() {
+            generate_to(*shell, &mut cmd, bin_name, out_dir)?;
+        }
+        generate_to(Nushell, &mut cmd, bin_name, out_dir)?;
+
+        Ok(())
+    }
+}
+
+fn main() -> Result<(), Box<dyn std::error::Error>> {
+    #[cfg(feature = "completions")]
+    completions::generate_completions()?;
+    Ok(())
+}