Handle the case where no args are given

1 files changed, 16 insertions, 4 deletions

diff --git a/bin/args.ml b/bin/args.ml
index e4e892c..90d65de 100644
--- a/bin/args.ml
+++ b/bin/args.ml
@@ -1,7 +1,10 @@
 module Report = Qsp_syntax.Report
 
 let input_files = ref []
-let usage = "qsp_parser input_file"
+
+let usage =
+  Printf.sprintf "%s input_file" (Filename.basename Sys.executable_name)
+
 let anon_fun filename = input_files := filename :: !input_files
 let level_value = ref None
 let reset_line = ref false
@@ -53,6 +56,15 @@ let speclist =
 let parse : unit -> string list * t =
  fun () ->
   let () = Arg.parse (Arg.align speclist) anon_fun usage in
-  let filters = { level = !level_value } in
-  ( !input_files,
-    { reset_line = !reset_line; filters; interractive = !interractive } )
+
+  match !input_files with
+  | [] ->
+      Arg.usage (Arg.align speclist) usage;
+      prerr_endline "";
+      prerr_endline "Error, you should provide at least one file to parse.";
+
+      exit 1
+  | _ ->
+      let filters = { level = !level_value } in
+      ( !input_files,
+        { reset_line = !reset_line; filters; interractive = !interractive } )