Add support for specifying additional command line arguments in a file using the syntax ``@file``.

1 files changed, 30 insertions, 0 deletions

diff --git a/argparse.py b/argparse.py
index 2aaf86a..fd8e4d2 100644
--- a/argparse.py
+++ b/argparse.py
@@ -1396,6 +1396,7 @@ class ArgumentParser(_AttributeHolder, _ActionsContainer):
                  parents=[],

                  formatter_class=HelpFormatter,

                  prefix_chars='-',

+                 fromfile_prefix_chars=None,

                  argument_default=None,

                  conflict_handler='error',

                  add_help=True):

@@ -1415,6 +1416,7 @@ class ArgumentParser(_AttributeHolder, _ActionsContainer):
         self.epilog = epilog

         self.version = version

         self.formatter_class = formatter_class

+        self.fromfile_prefix_chars = fromfile_prefix_chars

         self.add_help = add_help

 

         self._has_subparsers = False

@@ -1551,6 +1553,10 @@ class ArgumentParser(_AttributeHolder, _ActionsContainer):
             self.error(str(err))

 

     def _parse_known_args(self, arg_strings, namespace):

+        # replace arg strings that are file references

+        if self.fromfile_prefix_chars is not None:

+            arg_strings = self._read_args_from_files(arg_strings)

+

         # map all mutually exclusive arguments to the other arguments

         # they can't occur with

         action_conflicts = {}

@@ -1781,6 +1787,30 @@ class ArgumentParser(_AttributeHolder, _ActionsContainer):
         # return the updated namespace and the extra arguments

         return namespace, extras

 

+    def _read_args_from_files(self, arg_strings):

+        # expand arguments referencing files

+        new_arg_strings = []

+        for arg_string in arg_strings:

+

+            # for regular arguments, just add them back into the list

+            if arg_string[0] not in self.fromfile_prefix_chars:

+                new_arg_strings.append(arg_string)

+

+            # replace arguments referencing files with the file content

+            else:

+                try:

+                    args_file = open(arg_string[1:])

+                    arg_strings = args_file.read().splitlines()

+                    arg_strings = self._read_args_from_files(arg_strings)

+                    new_arg_strings.extend(arg_strings)

+                    args_file.close()

+                except IOError:

+                    err = _sys.exc_info()[1]

+                    self.error(str(err))

+

+        # return the modified argument list

+        return new_arg_strings

+

     def _match_argument(self, action, arg_strings_pattern):

         # match the pattern for this action to the arg strings

         nargs_pattern = self._get_nargs_pattern(action)