feat: generate shell completion

crates/tinymist/src/args.rs

@@ -13,15 +13,17 @@ pub struct CliArguments {
 
 #[derive(Debug, Clone, clap::Subcommand)]
 pub enum Commands {
-    /// Run Language Server
+    /// Generates completion script to stdout
+    Completion(ShellCompletionArgs),
+    /// Runs language server
     Lsp(LspArgs),
-    /// Run Language Server for tracing some typst program.
+    /// Runs language server for tracing some typst program.
     #[clap(hide(true))]
     TraceLsp(CompileArgs),
-    /// Run Preview Server
+    /// Runs preview server
     #[cfg(feature = "preview")]
     Preview(tinymist::tool::preview::PreviewCliArgs),
-    /// Probe
+    /// Probes existence (Nop run)
     Probe,
 }
 
@@ -31,6 +33,14 @@ impl Default for Commands {
     }
 }
 
+#[derive(Debug, Clone, clap::Parser)]
+pub struct ShellCompletionArgs {
+    /// The shell to generate the completion script for. If not provided, it
+    /// will be inferred from the environment.
+    #[clap(value_enum)]
+    pub shell: Option<clap_complete::Shell>,
+}
+
 #[derive(Debug, Clone, Default, clap::Parser)]
 pub struct CompileArgs {
     #[clap(long, default_value = "false")]

crates/tinymist/src/main.rs

@@ -2,10 +2,12 @@
 
 mod args;
 
-use std::{path::PathBuf, sync::Arc};
+use std::{io, path::PathBuf, sync::Arc};
 
 use anyhow::bail;
 use clap::Parser;
+use clap_builder::CommandFactory;
+use clap_complete::{generate, Shell};
 use comemo::Prehashed;
 use futures::future::MaybeDone;
 use lsp_server::RequestId;
@@ -20,7 +22,7 @@ use typst::{eval::Tracer, foundations::IntoValue, syntax::Span};
 use typst_ts_compiler::{CompileEnv, Compiler, TaskInputs};
 use typst_ts_core::{typst::prelude::EcoVec, TypstDict};
 
-use crate::args::{CliArguments, Commands, CompileArgs, LspArgs};
+use crate::args::*;
 
 #[cfg(feature = "dhat-heap")]
 #[global_allocator]
@@ -67,6 +69,7 @@ fn main() -> anyhow::Result<()> {
     let args = CliArguments::parse();
 
     match args.command.unwrap_or_default() {
+        Commands::Completion(args) => completion(args),
         Commands::Lsp(args) => lsp_main(args),
         Commands::TraceLsp(args) => trace_main(args),
         #[cfg(feature = "preview")]
@@ -80,6 +83,18 @@ fn main() -> anyhow::Result<()> {
     }
 }
 
+/// Generates completion script to stdout.
+pub fn completion(args: ShellCompletionArgs) -> anyhow::Result<()> {
+    let Some(shell) = args.shell.or_else(Shell::from_env) else {
+        anyhow::bail!("could not infer shell");
+    };
+
+    let mut cmd = CliArguments::command();
+    generate(shell, &mut cmd, "tinymist", &mut io::stdout());
+
+    Ok(())
+}
+
 /// The main entry point for the LSP server.
 pub fn lsp_main(args: LspArgs) -> anyhow::Result<()> {
     log::info!("starting LSP server: {:#?}", args);
@@ -107,7 +122,7 @@ pub fn lsp_main(args: LspArgs) -> anyhow::Result<()> {
 pub fn trace_main(args: CompileArgs) -> anyhow::Result<()> {
     let mut input = PathBuf::from(match args.compile.input {
         Some(value) => value,
-        None => return Err(anyhow::Error::msg("Provide a valid path")),
+        None => return Err(anyhow::anyhow!("provide a valid path")),
     });
 
     let mut root_path = args.compile.root.unwrap_or(PathBuf::from("."));