Require atleast one parameter to be provided

2 files changed, 6 insertions, 0 deletions

diff --git a/src/error.rs b/src/error.rs
index 06bfbbe..f303780 100644
--- a/src/error.rs
+++ b/src/error.rs
@@ -8,6 +8,7 @@ pub enum Error {
 	BadLengths,
 	DuplicateElems(Vec<String>),
 	IOError(io::Error),
+	NoArgs,
 	NoEditor,
 	SpawnFailed(String, io::Error),
 }
@@ -21,6 +22,7 @@ impl Display for Error {
 				|d| writeln!(f, "{p}: Multiple files named \"{}\" specified", d)
 			),
 			Self::IOError(e) => writeln!(f, "{p}: {e}"),
+			Self::NoArgs => writeln!(f, "Usage: {p} file ..."),
 			Self::NoEditor => writeln!(f, "{p}: \"EDITOR\" environment variable is not set"),
 			Self::SpawnFailed(ed, e) => writeln!(f, "{p}: Failed to spawn editor \"{ed}\": {e}")
 		}
diff --git a/src/main.rs b/src/main.rs
index 1c0d487..f4d1d34 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -29,6 +29,10 @@ fn main() -> MainResult {
 
 fn work() -> Result<(), Error> {
 	let old_files = env::args().skip(1).collect::<Vec<String>>();
+	if old_files.is_empty() {
+		return Err(Error::NoArgs);
+	}
+
 	let dups = duplicate_elements(old_files.clone());
 	if !dups.is_empty() {
 		return Err(Error::DuplicateElems(dups));