Fix interactive mode

Author: rayokota

README.md

@@ -61,7 +61,7 @@ options:
   -f {auto,json,string}, --format {auto,json,string}
                         Input format (default=auto)
   -o <arg>, --output <arg>
-                        JSON output file (- for stdin)
+                        JSON output file (default=stdout)
   -oc <arg>, --ocharset <arg>
                         Output character set (default=utf-8)
   -time                 Print performance timers to stderr
@@ -70,7 +70,7 @@ options:
                         JSONata variable bindings
   -bf <file>, --bindings-file <file>
                         JSONata variable bindings file
-  -it, --interactive    Interactive REPL
+  -it, --interactive    Interactive REPL (requires input file)
 ```
 
 ### Examples
@@ -100,6 +100,11 @@ helloworld.json
     "[email protected]"
   ]
 }
+
+% python3 -m jsonata.cli -i helloworld.json -it
+Enter an expression to have it evaluated.
+JSONata> (a & b)
+hello world
 ```
 
 ## Running Tests

src/jsonata/cli/__main__.py

@@ -54,7 +54,7 @@ def get_options(argv: Optional[list[str]] = None) -> argparse.ArgumentParser:
     )
     parser.add_argument(
         "-o", "--output", metavar="<arg>",
-        help="JSON output file (- for stdin)"
+        help="JSON output file (default=stdout)"
     )
     parser.add_argument(
         "-oc", "--ocharset", default="utf-8", metavar="<arg>",
@@ -78,7 +78,7 @@ def get_options(argv: Optional[list[str]] = None) -> argparse.ArgumentParser:
     )
     parser.add_argument(
         "-it", "--interactive", default=False, action="store_true",
-        help="Interactive REPL"
+        help="Interactive REPL (requires input file)"
     )
 
     # The expression
@@ -160,8 +160,9 @@ def main(argv: Optional[list[str]] = None) -> int:
     options = parser.parse_args(argv)
 
     if options.expression is None and options.expr is None:
-        parser.print_help()
-        return 1
+        if not options.interactive:
+            parser.print_help()
+            return 1
 
     icharset = options.icharset
     ocharset = options.icharset
@@ -187,6 +188,9 @@ def main(argv: Optional[list[str]] = None) -> int:
         bindings = json.loads(bindings_str)
 
     if options.input == '-' or options.input is None:
+        if options.interactive:
+            parser.print_help()
+            return 1
         input = sys.stdin.read()
     else:
         with open(options.input, 'r', encoding=icharset) as fd: