Add support for generating shell completions

Cargo.toml

@@ -25,6 +25,7 @@ path = "src/main.rs"
 [dependencies]
 ansi_term = "0.12.1"
 clap = { version = "4.1.1", features = ["derive"] }
+clap_complete = { version = "4.1.1", optional = true }
 crossbeam = "0.8.2"
 filesize = "0.2.0"
 ignore = "0.4.2"
@@ -35,3 +36,6 @@ once_cell = "1.17.0"
 indoc = "2.0.0"
 strip-ansi-escapes = "0.1.1"
 tempdir = "0.3"
+
+[features]
+completions = ["dep:clap_complete"]

src/main.rs

@@ -28,6 +28,20 @@ fn main() -> ExitCode {
 fn run() -> Result<(), Box<dyn std::error::Error>> {
     tree::ui::init();
     let ctx = Context::init()?;
+
+    #[cfg(feature = "completions")]
+    {
+        use std::io::stdout;
+        use clap::CommandFactory;
+
+        let bin_name = "et";
+
+        if let Some(shell) = ctx.completions {
+            clap_complete::generate(shell, &mut Context::command(), bin_name, &mut stdout().lock());
+            return Ok(());
+        }
+    }
+
     let tree = Tree::init(ctx)?;
 
     println!("{tree}");

src/render/context/mod.rs

@@ -107,6 +107,11 @@ pub struct Context {
     /// Don't read configuration file
     #[arg(long)]
     pub no_config: bool,
+
+    #[cfg(feature = "completions")]
+    #[arg(long)]
+    /// Print completions for a given shell to stdout
+    pub completions: Option<clap_complete::Shell>,
 }
 
 impl Context {