Generate shell completions at build time

b3sum/Cargo.lock

@@ -75,6 +75,7 @@ dependencies = [
  "anyhow",
  "blake3",
  "clap",
+ "clap_complete",
  "clap_mangen",
  "duct",
  "hex",
@@ -137,6 +138,15 @@ dependencies = [
  "terminal_size",
 ]
 
+[[package]]
+name = "clap_complete"
+version = "4.5.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "dd79504325bf38b10165b02e89b4347300f855f273c4cb30c4a3209e6583275e"
+dependencies = [
+ "clap",
+]
+
 [[package]]
 name = "clap_derive"
 version = "4.5.0"

b3sum/Cargo.toml

@@ -28,4 +28,5 @@ tempfile = "3.1.0"
 [build-dependencies]
 blake3 = { version = "1", path = ".." }
 clap = { version = "4.0.8", features = ["derive"] }
+clap_complete = "4.5.2"
 clap_mangen = "0.2.20"

b3sum/build.rs

@@ -2,6 +2,23 @@ use clap::CommandFactory;
 
 include!("src/cli.rs");
 
+fn generate_completions(out_dir: &std::path::Path) -> std::io::Result<()> {
+    fn generate_to(
+        gen: impl clap_complete::Generator,
+        out_dir: &std::path::Path,
+    ) -> std::io::Result<std::path::PathBuf> {
+        let mut command = Inner::command();
+        clap_complete::generate_to(gen, &mut command, "b3sum", out_dir)
+    }
+
+    generate_to(clap_complete::Shell::Bash, out_dir)?;
+    generate_to(clap_complete::Shell::Elvish, out_dir)?;
+    generate_to(clap_complete::Shell::Fish, out_dir)?;
+    generate_to(clap_complete::Shell::PowerShell, out_dir)?;
+    generate_to(clap_complete::Shell::Zsh, out_dir)?;
+    Ok(())
+}
+
 fn generate_man_page(out_dir: &std::path::Path) -> std::io::Result<()> {
     let command = Inner::command();
 
@@ -54,6 +71,7 @@ fn main() -> std::io::Result<()> {
     let out_dir = std::env::var("OUT_DIR").expect("environment variable `OUT_DIR` not defined");
     let out_dir = std::path::PathBuf::from(out_dir);
 
+    generate_completions(&out_dir)?;
     generate_man_page(&out_dir)?;
     Ok(())
 }

b3sum/src/cli.rs

@@ -1,4 +1,4 @@
-use clap::Parser;
+use clap::{Parser, ValueHint};
 use std::path::PathBuf;
 
 const DERIVE_KEY_ARG: &str = "derive_key";
@@ -17,6 +17,7 @@ pub struct Inner {
     /// Files to hash, or checkfiles to check
     ///
     /// When no file is given, or when - is given, read standard input.
+    #[arg(value_hint(ValueHint::FilePath))]
     pub file: Vec<PathBuf>,
 
     /// Use the keyed mode, reading the 32-byte key from stdin