Closes #200 substitute command line arguments for defaults

README.md

@@ -264,6 +264,7 @@ Just about everything in Gooey's overall look and feel can be customized by pass
 | show_restart_button | Toggles whether or not to show the restart button at the end of execution |
 | run_validators | Controls whether or not to have Gooey perform validation before calling your program |
 | poll_external_updates | (Experimental!) When True, Gooey will call your code with a `gooey-seed-ui` CLI argument and use the response to fill out dynamic values in the UI (See: [Using Dynamic Values](#using-dynamic-values))|
+| use_cmd_args | Substitute any command line arguments provided at run time for the default values specified in the Gooey configuration |
 | return_to_config | When True, Gooey will return to the configuration settings window upon successful run |
 | progress_regex | A text regex used to pattern match runtime progress information. See: [Showing Progress](#showing-progress) for a detailed how-to | 
 | progress_expr | A python expression applied to any matches found via the `progress_regex`. See: [Showing Progress](#showing-progress) for a detailed how-to |

gooey/python_bindings/cmd_args.py

@@ -0,0 +1,79 @@
+'''
+Created on Jan 15 2019
+
+@author: Jonathan Schultz
+
+This file contains code that allows the default argument values to be specified
+on the command line.
+'''
+
+from argparse import _SubParsersAction
+
+def parse_cmd_args(self, args=None):
+
+  def prepare_to_read_cmd_args(item):
+    '''
+    Before reading the command-line arguments, we need to fudge a few things:
+      1. If there are subparsers, we need a dest in order to know in which
+         subparser the command-line values should be stored.
+      2. Any required argument or mutex group needs to be made not required,
+         otherwise it will be compulsory to enter those values on the command
+         line.
+    We save the everything as it was before the fudge, so we can restore later.
+    '''
+    for action in item._actions:
+      if isinstance(action, _SubParsersAction):
+        action.save_dest = action.dest
+        if not action.dest:
+          action.dest = '_subparser'
+      else:
+        action.save_required = action.required
+        action.required = False
+        action.save_nargs = action.nargs
+        if action.nargs == '+':
+          action.nargs = '*'
+        elif action.nargs is None:
+          action.nargs = '?'
+
+    for mutex_group in item._mutually_exclusive_groups:
+      mutex_group.save_required = mutex_group.required
+      mutex_group.required = False
+
+  def overwrite_default_values(item, cmd_args):
+    '''
+    Subsistute arguments provided on the command line in the place of the
+    default values provided to argparse.
+    '''
+    for action in item._actions:
+      if isinstance(action, _SubParsersAction):
+        subparser_arg = getattr(cmd_args, action.dest, None)
+        if subparser_arg:
+          overwrite_default_values(action.choices[subparser_arg], cmd_args)
+      else:
+        dest = getattr(action, 'dest', None)
+        if dest:
+          cmd_arg = getattr(cmd_args, dest, None)
+          if cmd_arg:
+            action.default = cmd_arg
+
+  def restore_original_configuration(item):
+    '''
+    Restore the old values as they were to start with.
+    '''
+    for action in item._actions:
+      if isinstance(action, _SubParsersAction):
+        action.dest = action.save_dest
+        del action.save_dest
+      else:
+        action.required = action.save_required
+        del action.save_required
+        action.nargs = action.save_nargs
+        del action.save_nargs
+
+    for mutex_group in item._mutually_exclusive_groups:
+      mutex_group.required = mutex_group.save_required
+      del mutex_group.save_required
+
+  prepare_to_read_cmd_args(self)
+  overwrite_default_values(self, self.original_parse_args(args))
+  restore_original_configuration(self)

gooey/python_bindings/gooey_decorator.py

@@ -14,6 +14,7 @@ from argparse import ArgumentParser
 from gooey.gui.util.freeze import getResourcePath
 from gooey.util.functional import merge
 from . import config_generator
+from . import cmd_args
 
 IGNORE_COMMAND = '--ignore-gooey'
 
@@ -43,6 +44,7 @@ def Gooey(f=None,
           header_height=80,
           navigation='SIDEBAR', # TODO: add this to the docs
           tabbed_groups=False,
+          use_cmd_args=False,
           **kwargs):
   '''
   Decorator for client code's main function.
@@ -68,6 +70,9 @@ def Gooey(f=None,
           sys.exit(1)
 
       if not build_spec:
+        if use_cmd_args:
+          cmd_args.parse_cmd_args(self, args)
+
         build_spec = config_generator.create_from_parser(
           self,
           source_path,

gooey/tests/test_cmd_args.py

@@ -0,0 +1,61 @@
+import unittest
+
+from gooey import GooeyParser
+from gooey.python_bindings import cmd_args
+from argparse import ArgumentParser
+
+class TextCommandLine(unittest.TestCase):
+
+    def test_default_overwritten(self):
+        parser = GooeyParser()
+        ArgumentParser.original_parse_args = ArgumentParser.parse_args
+
+        parser.add_argument('arg', type=int, default=0)
+
+        # Supply 1 as command line argument, check that it overwrites argparse default
+        cmd_args.parse_cmd_args(parser, ['1'])
+        argdefault = next(action for action in parser._actions if action.dest == 'arg').default
+        self.assertEqual(argdefault, 1)
+
+    def test_required_not_enforced(self):
+        parser = GooeyParser()
+        ArgumentParser.original_parse_args = ArgumentParser.parse_args
+
+        parser.add_argument('--arg', type=int, required=True)
+        parser.add_argument('--argn', type=int, nargs='+')
+        parser.add_argument('argp', type=int)
+        mutex=parser.add_mutually_exclusive_group(required=True)
+        mutex.add_argument('--one', action='store_true')
+        mutex.add_argument('--two', action='store_true')
+
+        # No error when we don't provide required arguments
+        cmd_args.parse_cmd_args(parser)
+
+        # Test that required/argn have been restored in parser
+        argrequired = next(action for action in parser._actions if action.dest == 'arg').required
+        self.assertEqual(argrequired, True)
+        argnnargs = next(action for action in parser._actions if action.dest == 'argn').nargs
+        self.assertEqual(argnnargs, '+')
+        argpnargs = next(action for action in parser._actions if action.dest == 'argp').nargs
+        self.assertEqual(argpnargs, None)
+        mutexrequired = next(mutex for mutex in parser._mutually_exclusive_groups).required
+        self.assertEqual(mutexrequired, True)
+
+    def test_cmd_args_subparser(self):
+        parser = GooeyParser()
+        subparsers = parser.add_subparsers(dest='subparser')
+        subparserA = subparsers.add_parser('A')
+        subparserB = subparsers.add_parser('B')
+        subparserA.add_argument('argA', type=int, default=0)
+        subparserB.add_argument('argB', type=int, default=0)
+
+        ArgumentParser.original_parse_args = ArgumentParser.parse_args
+
+        cmd_args.parse_cmd_args(parser, ['A', '1'])
+
+        # Check that argA is overwritten but not argB
+        subparseraction = next(action for action in parser._actions if action.dest == 'subparser')
+        argAdefault = next(action for action in subparseraction.choices['A']._actions if action.dest == 'argA').default
+        self.assertEqual(argAdefault, 1)
+        argBdefault = next(action for action in subparseraction.choices['B']._actions if action.dest == 'argB').default
+        self.assertEqual(argBdefault, 0)