Clean up help metavar for --scope configuration options

- previously commands with this argument showed a long list of choices
  that were platform specific.

- use a better metavar: {defaults,system,site,user}[/PLATFORM]

lib/spack/spack/cmd/compiler.py

@@ -54,7 +54,8 @@ def setup_parser(subparser):
         help='search the system for compilers to add to Spack configuration')
     find_parser.add_argument('add_paths', nargs=argparse.REMAINDER)
     find_parser.add_argument(
-        '--scope', choices=scopes, default=spack.cmd.default_modify_scope,
+        '--scope', choices=scopes, metavar=spack.config.scopes_metavar,
+        default=spack.cmd.default_modify_scope,
         help="configuration scope to modify")
 
     # Remove
@@ -65,20 +66,23 @@ def setup_parser(subparser):
         help='remove ALL compilers that match spec')
     remove_parser.add_argument('compiler_spec')
     remove_parser.add_argument(
-        '--scope', choices=scopes, default=spack.cmd.default_modify_scope,
+        '--scope', choices=scopes, metavar=spack.config.scopes_metavar,
+        default=spack.cmd.default_modify_scope,
         help="configuration scope to modify")
 
     # List
     list_parser = sp.add_parser('list', help='list available compilers')
     list_parser.add_argument(
-        '--scope', choices=scopes, default=spack.cmd.default_list_scope,
+        '--scope', choices=scopes, metavar=spack.config.scopes_metavar,
+        default=spack.cmd.default_list_scope,
         help="configuration scope to read from")
 
     # Info
     info_parser = sp.add_parser('info', help='show compiler paths')
     info_parser.add_argument('compiler_spec')
     info_parser.add_argument(
-        '--scope', choices=scopes, default=spack.cmd.default_list_scope,
+        '--scope', choices=scopes, metavar=spack.config.scopes_metavar,
+        default=spack.cmd.default_list_scope,
         help="configuration scope to read from")
 
 

lib/spack/spack/cmd/compilers.py

@@ -31,8 +31,10 @@
 
 
 def setup_parser(subparser):
-    subparser.add_argument('--scope', choices=spack.config.config_scopes,
+    scopes = spack.config.config_scopes
-                           help="configuration scope to read/modify")
+    subparser.add_argument(
+        '--scope', choices=scopes, metavar=spack.config.scopes_metavar,
+        help="configuration scope to read/modify")
 
 
 def compilers(parser, args):

lib/spack/spack/cmd/config.py

@@ -31,8 +31,10 @@
 
 def setup_parser(subparser):
     # User can only choose one
-    subparser.add_argument('--scope', choices=spack.config.config_scopes,
+    subparser.add_argument(
-                           help="configuration scope to read/modify")
+        '--scope', choices=spack.config.config_scopes,
+        metavar=spack.config.scopes_metavar,
+        help="configuration scope to read/modify")
 
     sp = subparser.add_subparsers(metavar='SUBCOMMAND', dest='config_command')
 

lib/spack/spack/cmd/mirror.py

@@ -75,7 +75,8 @@ def setup_parser(subparser):
     add_parser.add_argument(
         'url', help="url of mirror directory from 'spack mirror create'")
     add_parser.add_argument(
-        '--scope', choices=scopes, default=spack.cmd.default_modify_scope,
+        '--scope', choices=scopes, metavar=spack.config.scopes_metavar,
+        default=spack.cmd.default_modify_scope,
         help="configuration scope to modify")
 
     # Remove
@@ -83,13 +84,15 @@ def setup_parser(subparser):
                                   help=mirror_remove.__doc__)
     remove_parser.add_argument('name')
     remove_parser.add_argument(
-        '--scope', choices=scopes, default=spack.cmd.default_modify_scope,
+        '--scope', choices=scopes, metavar=spack.config.scopes_metavar,
+        default=spack.cmd.default_modify_scope,
         help="configuration scope to modify")
 
     # List
     list_parser = sp.add_parser('list', help=mirror_list.__doc__)
     list_parser.add_argument(
-        '--scope', choices=scopes, default=spack.cmd.default_list_scope,
+        '--scope', choices=scopes, metavar=spack.config.scopes_metavar,
+        default=spack.cmd.default_list_scope,
         help="configuration scope to read from")
 
 

lib/spack/spack/cmd/repo.py

@@ -52,7 +52,8 @@ def setup_parser(subparser):
     # List
     list_parser = sp.add_parser('list', help=repo_list.__doc__)
     list_parser.add_argument(
-        '--scope', choices=scopes, default=spack.cmd.default_list_scope,
+        '--scope', choices=scopes, metavar=spack.config.scopes_metavar,
+        default=spack.cmd.default_list_scope,
         help="configuration scope to read from")
 
     # Add
@@ -60,7 +61,8 @@ def setup_parser(subparser):
     add_parser.add_argument(
         'path', help="path to a Spack package repository directory")
     add_parser.add_argument(
-        '--scope', choices=scopes, default=spack.cmd.default_modify_scope,
+        '--scope', choices=scopes, metavar=spack.config.scopes_metavar,
+        default=spack.cmd.default_modify_scope,
         help="configuration scope to modify")
 
     # Remove
@@ -70,7 +72,8 @@ def setup_parser(subparser):
         'path_or_namespace',
         help="path or namespace of a Spack package repository")
     remove_parser.add_argument(
-        '--scope', choices=scopes, default=spack.cmd.default_modify_scope,
+        '--scope', choices=scopes, metavar=spack.config.scopes_metavar,
+        default=spack.cmd.default_modify_scope,
         help="configuration scope to modify")
 
 

lib/spack/spack/config.py

@@ -88,6 +88,10 @@
 #: Later scopes will override earlier scopes.
 config_scopes = OrderedDict()
 
+#: metavar to use for commands that accept scopes
+#: this is shorter and more readable than listing all choices
+scopes_metavar = '{defaults,system,site,user}[/PLATFORM]'
+
 
 def validate_section_name(section):
     """Exit if the section is not a valid section."""