make completion cmd a subcommand of shell args

README.md

@@ -241,21 +241,24 @@ systemctl --user start  himalaya.service
 ## Completions
 
 ```sh
-# For bash shells
-himalaya bash-completions
+Generates the completion script for the given shell
 
-# For zsh shells
-himalaya zsh-completions
+USAGE:
+    himalaya completion <shell>
 
-# For fish shells
-himalaya fish-completions
+FLAGS:
+    -h, --help       Prints help information
+    -V, --version    Prints version information
+
+ARGS:
+    <shell>     [possible values: bash, zsh, fish]
 ```
 
-Those commands print the generated scripts to the stdout. You will have
+The command prints the generated script to the stdout. You will have
 to manually save and source them. For example:
 
 ```sh
-himalaya bash-completions > himalaya-completions.bash
+himalaya completion bash > himalaya-completions.bash
 ```
 
 ```sh

src/completion/cli.rs

@@ -1,34 +1,27 @@
-use clap::{self, App, ArgMatches, SubCommand};
+use clap::{self, App, Arg, ArgMatches, Shell, SubCommand};
 use error_chain::error_chain;
 use std::io;
 
 error_chain! {}
 
 pub fn completion_subcmds<'a>() -> Vec<App<'a, 'a>> {
-    vec![
-        SubCommand::with_name("bash-completions").about("Generates bash completions script"),
-        SubCommand::with_name("zsh-completions").about("Generates zsh completions script"),
-        SubCommand::with_name("fish-completions").about("Generates fish completions script"),
-    ]
+    vec![SubCommand::with_name("completion")
+        .about("Generates the completion script for the given shell")
+        .args(&[Arg::with_name("shell")
+            .possible_values(&["bash", "zsh", "fish"])
+            .required(true)])]
 }
 
 pub fn completion_matches(mut app: App, matches: &ArgMatches) -> Result<bool> {
-    use clap::Shell::*;
-
-    if matches.is_present("bash-completions") {
-        app.gen_completions_to("himalaya", Bash, &mut io::stdout());
+    if let Some(matches) = matches.subcommand_matches("completion") {
+        let shell = match matches.value_of("shell").unwrap() {
+            "fish" => Shell::Fish,
+            "zsh" => Shell::Zsh,
+            "bash" | _ => Shell::Bash,
+        };
+        app.gen_completions_to("himalaya", shell, &mut io::stdout());
         return Ok(true);
-    }
-
-    if matches.is_present("zsh-completions") {
-        app.gen_completions_to("himalaya", Zsh, &mut io::stdout());
-        return Ok(true);
-    }
-
-    if matches.is_present("fish-completions") {
-        app.gen_completions_to("himalaya", Fish, &mut io::stdout());
-        return Ok(true);
-    }
+    };
 
     Ok(false)
 }