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

@@ -102,15 +102,17 @@ OPTIONS:
             Assume "yes" instead of prompting when removing empty directories
 
 SUBCOMMANDS:
-    deploy      Deploy the files to their respective targets. This is the default subcommand
-    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
-                    package
-    undeploy    Delete all deployed files from their target locations. Note that this operates
-                    on all files that are currently in cache
-    watch       Run continuously, watching the repository for changes and deploying as soon as
-                    they happen. Can be ran with `--dry-run`
+    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 package
+    undeploy           Delete all deployed files from their target locations. Note that this
+                           operates on all files that are currently in cache
+    watch              Run continuously, watching the repository for changes and deploying as
+                           soon as they happen. Can be ran with `--dry-run`
 ```
 
 # Contributing

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 +108,14 @@ 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)