Adding generation of shell completions

Cargo.toml

@@ -13,6 +13,7 @@ license = "Unlicense"
 [dependencies]
 anyhow = "1.*"
 clap = { version = "3.*", features = ["derive"] }
+clap_complete = "3.*"
 crossterm = "0.18.*"
 diff = "0.1.*"
 handlebars = { version = "4.*", features = ["script_helper"] }

README.md

@@ -103,6 +103,7 @@ OPTIONS:
 
 SUBCOMMANDS:
     deploy      Deploy the files to their respective targets. This is the default subcommand
+    gen-completions    Generate shell completions
     help        Print this message or the help of the given subcommand(s)
     init        Initialize global.toml with a single package containing all the files in the
                     current directory pointing to a dummy value and a local.toml that selects that

src/args.rs

@@ -1,6 +1,7 @@
 use std::path::PathBuf;
 
 use clap::{Parser, Subcommand};
+use clap_complete::Shell;
 
 /// A small dotfile manager.
 #[derive(Debug, Parser, Default, Clone)]
@@ -102,6 +103,13 @@ pub enum Action {
     /// Run continuously, watching the repository for changes and deploying as soon as they
     /// happen. Can be ran with `--dry-run`
     Watch,
+
+    /// Generate shell completions
+    GenCompletions {
+        /// Set the shell for generating completions [values: bash, elvish, fish, powerShell, zsh]
+        #[clap(long, short)]
+        shell: Shell,
+    }
 }
 
 impl Default for Action {

src/main.rs

@@ -12,7 +12,11 @@ mod hooks;
 mod init;
 mod watch;
 
+use std::io;
+
 use anyhow::{Context, Result};
+use clap::CommandFactory;
+use clap_complete::generate;
 
 fn main() {
     match run() {
@@ -104,6 +108,9 @@ Otherwise, run `dotter undeploy` as root, remove cache.toml and cache/ folders,
                 .block_on(watch::watch(opt))
                 .context("watch repository")?;
         }
+        args::Action::GenCompletions { shell } => {
+            generate(shell, &mut args::Options::command(), "dotter", &mut io::stdout());
+        }
     }
 
     Ok(true)