feat: add generate-shell-completion subcommand

Author: akiomik

src/command.rs

@@ -1,19 +1,21 @@
 use std::path::PathBuf;
 
-use clap::Subcommand;
+use clap::{Subcommand, ValueHint};
+use clap_complete::Shell;
 use globset::Glob;
 
 use crate::output::Format;
 
 pub mod check;
+pub mod generate_shell_completion;
 
 #[derive(Subcommand)]
 #[allow(clippy::exhaustive_enums)]
 pub enum Command {
     /// Check markdown on the given files or directories
     Check {
         /// List of files or directories to check
-        #[arg(default_value = ".")]
+        #[arg(default_value = ".", value_hint = ValueHint::AnyPath)]
         files: Vec<PathBuf>,
 
         /// Output format for violations. The default format is "concise"
@@ -28,4 +30,9 @@ pub enum Command {
         #[arg(long, value_delimiter = ',')]
         exclude: Option<Vec<Glob>>,
     },
+    /// Generate shell completion
+    GenerateShellCompletion {
+        /// Shell to generate a completion script
+        shell: Shell,
+    },
 }

src/command/generate_shell_completion.rs

@@ -0,0 +1,23 @@
+use std::io;
+
+use clap::Command;
+use clap_complete::{generate, Generator};
+
+#[derive(Debug, Clone)]
+pub struct ShellCompletionGenerator {
+    cmd: Command,
+}
+
+impl ShellCompletionGenerator {
+    #[inline]
+    #[must_use]
+    pub const fn new(cmd: Command) -> Self {
+        Self { cmd }
+    }
+
+    #[inline]
+    pub fn generate<G: Generator>(&mut self, gen: G) {
+        let name = self.cmd.get_name().to_owned();
+        generate(gen, &mut self.cmd, name, &mut io::stdout());
+    }
+}

src/main.rs

@@ -17,11 +17,13 @@ static GLOBAL: mimalloc::MiMalloc = mimalloc::MiMalloc;
 
 use std::process::ExitCode;
 
+use clap::CommandFactory as _;
 use clap::Parser as _;
 use mado::command::check::Options;
 use miette::Result;
 
 use mado::command::check::Checker;
+use mado::command::generate_shell_completion::ShellCompletionGenerator;
 use mado::Cli;
 use mado::Command;
 
@@ -45,5 +47,11 @@ fn main() -> Result<ExitCode> {
             let checker = Checker::new(files, config)?;
             checker.check()
         }
+        Command::GenerateShellCompletion { shell } => {
+            let cmd = Cli::command();
+            let mut generator = ShellCompletionGenerator::new(cmd);
+            generator.generate(*shell);
+            Ok(ExitCode::SUCCESS)
+        }
     }
 }

tests/command_generate_shell_completion.rs

@@ -0,0 +1,26 @@
+use assert_cmd::Command;
+use indoc::indoc;
+use miette::{IntoDiagnostic as _, Result};
+
+#[test]
+fn generate_shell_completion_zsh() -> Result<()> {
+    let mut cmd = Command::cargo_bin("mado").into_diagnostic()?;
+    let assert = cmd.args(["generate-shell-completion", "zsh"]).assert();
+    assert.success();
+    Ok(())
+}
+
+#[test]
+fn generate_shell_completion_invalid() -> Result<()> {
+    let mut cmd = Command::cargo_bin("mado").into_diagnostic()?;
+    let assert = cmd.args(["generate-shell-completion", "foo"]).assert();
+    assert
+        .failure()
+        .stderr(indoc! {"
+            \u{1b}[1m\u{1b}[31merror:\u{1b}[0m invalid value \'\u{1b}[33mfoo\u{1b}[0m\' for \'\u{1b}[1m<SHELL>\u{1b}[0m\'
+              [possible values: \u{1b}[32mbash\u{1b}[0m, \u{1b}[32melvish\u{1b}[0m, \u{1b}[32mfish\u{1b}[0m, \u{1b}[32mpowershell\u{1b}[0m, \u{1b}[32mzsh\u{1b}[0m]
+            
+            For more information, try \'\u{1b}[1m--help\u{1b}[0m\'.
+        "});
+    Ok(())
+}