Add ability to use and save options in files (#314)

requirements.in

@@ -2,3 +2,4 @@ reportlab
 Pillow
 pre-commit
 pytest
+configargparse

requirements.txt

@@ -8,6 +8,7 @@ aspy.yaml==1.3.0          # via pre-commit
 atomicwrites==1.3.0       # via pytest
 attrs==19.3.0             # via pytest
 cfgv==2.0.1               # via pre-commit
+configargparse==1.2
 identify==1.4.7           # via pre-commit
 importlib-metadata==0.23  # via pluggy, pre-commit, pytest
 more-itertools==7.2.0     # via pytest, zipp

src/domdiv/main.py

@@ -2,7 +2,7 @@
 import codecs
 import json
 import sys
-import argparse
+import configargparse
 import copy
 import fnmatch
 import pkg_resources
@@ -131,8 +131,8 @@ def add_opt(options, option, value):
 
 
 def parse_opts(cmdline_args=None):
-    parser = argparse.ArgumentParser(
-        formatter_class=argparse.ArgumentDefaultsHelpFormatter,
+    parser = configargparse.ArgParser(
+        formatter_class=configargparse.ArgumentDefaultsHelpFormatter,
         description="Generate Dominion Dividers",
         epilog="Source can be found at 'https://github.com/sumpfork/dominiontabs'. "
         "An online version can be found at 'http://domtabs.sandflea.org/'. ",
@@ -747,6 +747,17 @@ def parse_opts(cmdline_args=None):
         dest="write_json",
         help="Write json version of card definitions and extras.",
     )
+    group_special.add_argument(
+        "-c",
+        is_config_file=True,
+        help="Use the specified configuration file to provide options. "
+        "Command line options override options from this file.",
+    )
+    group_special.add_argument(
+        "-w",
+        is_write_out_config_file_arg=True,
+        help="Write out the given options to the specified configuration file.",
+    )
 
     options = parser.parse_args(args=cmdline_args)
     # Need to do these while we have access to the parser