From 0baa9d6b3230581043771ff9b4b846be912b7b23 Mon Sep 17 00:00:00 2001
From: Caleb Maclennan <caleb@alerque.com>
Date: Sat, 24 Aug 2024 00:19:27 +0300
Subject: [PATCH] feat(cli): Catch missing required arguments at parse time

---
 src/cli.rs | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/cli.rs b/src/cli.rs
index e0a8f4b4c..5e0e4ef81 100644
--- a/src/cli.rs
+++ b/src/cli.rs
@@ -1,4 +1,4 @@
-use clap::Parser;
+use clap::{Parser, ValueHint};
 use std::path::PathBuf;
 
 /// The SILE Typesetter reads input file(s) and typesets the content into a rendered document
@@ -85,7 +85,7 @@ pub struct Cli {
     /// An extension will be chosen based on the output backend, typically .pdf.
     /// With this option any arbitrary name and path can be given.
     /// Additionally `-` can be used to write the output to STDOUT.
-    #[clap(short, long, value_name = "FILE")]
+    #[clap(short, long, value_name = "FILE", required_if_eq("input", "-"))]
     pub output: Option<PathBuf>,
 
     /// Set or override document class options.