Add pile doc

crates/pile/src/command/mod.rs

@@ -1,6 +1,8 @@
 use anyhow::Result;
-use clap::Subcommand;
-use pile_toolbox::cancelabletask::{CancelFlag, CancelableTask, CancelableTaskError};
+use clap::{CommandFactory, Subcommand};
+use pile_toolbox::cancelabletask::{
+	CancelFlag, CancelableTask, CancelableTaskError, CancelableTaskResult,
+};
 
 mod annotate;
 mod check;
@@ -9,10 +11,14 @@ mod init;
 mod lookup;
 mod probe;
 
-use crate::GlobalContext;
+use crate::{Cli, GlobalContext};
 
 #[derive(Debug, Subcommand)]
 pub enum SubCommand {
+	/// Print help for all subcommands
+	#[clap(alias = "doc")]
+	Docs {},
+
 	/// Annotate all items with a field, writing it to a sidecar path
 	Annotate {
 		#[command(flatten)]
@@ -59,6 +65,13 @@ impl CliCmdDispatch for SubCommand {
 			Self::Index { cmd } => cmd.start(ctx),
 			Self::Lookup { cmd } => cmd.start(ctx),
 			Self::Probe { cmd } => cmd.start(ctx),
+
+			Self::Docs {} => {
+				print_help_recursively(&mut Cli::command(), None);
+				return Ok(CancelableTask::spawn(|_| async {
+					CancelableTaskResult::Finished(Ok(0))
+				}));
+			}
 		}
 	}
 }
@@ -80,3 +93,26 @@ pub(super) trait CliCmd: Sized + Send + 'static {
 		flag: CancelFlag,
 	) -> impl std::future::Future<Output = Result<i32, CancelableTaskError<anyhow::Error>>> + Send;
 }
+
+#[expect(clippy::print_stdout)]
+fn print_help_recursively(command: &mut clap::Command, parent: Option<&str>) {
+	if command.get_name() == "help" || command.get_name() == "docs" {
+		return;
+	}
+
+	let parent = match parent {
+		None => command.get_name().into(),
+		Some(parent) => format!("{parent} {}", command.get_name()),
+	};
+
+	let b = "=".repeat(parent.len());
+	println!("============{b}===");
+	println!("# Docs for `{parent}` #");
+	println!("============{b}===");
+	println!("{}", command.render_help());
+
+	for subcommand in command.get_subcommands_mut() {
+		println!();
+		print_help_recursively(subcommand, Some(&parent));
+	}
+}