Support generating shell completions

CHANGELOG.md

@@ -30,6 +30,7 @@ All notable changes to eww will be listed here, starting at changes since versio
 - Add `unindent` property to the label widget, allowing to disable removal of leading spaces (By: nrv)
 - Switch to stable rust toolchain (1.76)
 - Add `tooltip` widget, which allows setting a custom tooltip (not only text), to a widget (By: Rayzeq)
+- Add `eww shell-completions` command, generating completion scripts for different shells
 
 ## [0.4.0] (04.09.2022)
 

Cargo.toml

@@ -14,6 +14,7 @@ cached = "0.48.0"
 chrono = "0.4.26"
 chrono-tz = "0.8.2"
 clap = {version = "4.5.1", features = ["derive"] }
+clap_complete = "4.5.1"
 codespan-reporting = "0.11"
 derive_more = "0.99"
 extend = "1.2"

crates/eww/Cargo.toml

@@ -38,6 +38,7 @@ anyhow.workspace  = true
 bincode.workspace = true
 chrono.workspace = true
 clap = {workspace = true, features = ["derive"] }
+clap_complete.workspace = true
 codespan-reporting.workspace = true
 derive_more.workspace = true
 extend.workspace = true

crates/eww/src/client.rs

@@ -6,6 +6,7 @@ use crate::{
     paths::EwwPaths,
 };
 use anyhow::{Context, Result};
+use clap::CommandFactory as _;
 use std::{
     io::{Read, Write},
     os::unix::net::UnixStream,
@@ -20,6 +21,9 @@ pub fn handle_client_only_action(paths: &EwwPaths, action: ActionClientOnly) ->
                 .spawn()?
                 .wait()?;
         }
+        ActionClientOnly::ShellCompletions { shell } => {
+            clap_complete::generate(shell, &mut opts::RawOpt::command(), "eww", &mut std::io::stdout());
+        }
     }
     Ok(())
 }

crates/eww/src/opts.rs

@@ -28,7 +28,7 @@ pub struct Opt {
 #[derive(Parser, Debug, Serialize, Deserialize, PartialEq)]
 #[clap(author = "ElKowar")]
 #[clap(version, about)]
-struct RawOpt {
+pub(super) struct RawOpt {
     /// Write out debug logs. (To read the logs, run `eww logs`).
     #[arg(long = "debug", global = true)]
     log_debug: bool,
@@ -75,6 +75,13 @@ pub enum ActionClientOnly {
     /// Print and watch the eww logs
     #[command(name = "logs")]
     Logs,
+
+    /// Generate a shell completion script
+    ShellCompletions {
+        #[arg(short, long)]
+        #[serde(with = "serde_shell")]
+        shell: clap_complete::shells::Shell,
+    },
 }
 
 #[derive(Subcommand, Debug, Serialize, Deserialize, PartialEq)]
@@ -303,3 +310,19 @@ where
 fn parse_duration(s: &str) -> Result<std::time::Duration, simplexpr::dynval::ConversionError> {
     DynVal::from_string(s.to_owned()).as_duration()
 }
+
+mod serde_shell {
+    use std::str::FromStr as _;
+
+    use clap_complete::Shell;
+    use serde::{Deserialize as _, Deserializer, Serialize as _, Serializer};
+
+    pub fn serialize<S: Serializer>(shell: &Shell, serializer: S) -> Result<S::Ok, S::Error> {
+        shell.to_string().serialize(serializer)
+    }
+
+    pub fn deserialize<'de, D: Deserializer<'de>>(deserializer: D) -> Result<Shell, D::Error> {
+        let s = String::deserialize(deserializer)?;
+        Shell::from_str(&s).map_err(serde::de::Error::custom)
+    }
+}