Read csv from stdin too

src/main.rs

@@ -110,13 +110,14 @@ fn main() {
         )
         .get_matches();
     if let Some(_matches) = matches.subcommand_matches("csv") {
-        if let Some(path) = _matches.get_one::<String>("path") {
-            let mut ldf = LazyFrame::default();
-            if _matches.get_flag("stdin") {
-                ldf = io::load_csv_from_stdin();
+        let mut ldf = if _matches.get_flag("stdin") {
+            io::load_csv_from_stdin()
         } else {
-                ldf = io::read_csv(path.to_string());
-            }
+            let path = _matches
+                .get_one::<String>("path")
+                .expect("Please, provide a file");
+            io::read_csv(path.to_string())
+        };
         if let Some(query) = _matches.get_one::<String>("query") {
             ldf = sql::execute(ldf, query);
         }
@@ -137,7 +138,6 @@ fn main() {
                 }
             }
         }
-        }
     } else if let Some(_matches) = matches.subcommand_matches("sql") {
         if let Some(statement) = _matches.get_one::<String>("statement") {
             let ldf = if _matches.get_flag("text") {