Add support for --table option in contents

Author: dwhswenson

paths_cli/commands/contents.py

@@ -1,19 +1,45 @@
 import click
 from paths_cli.parameters import INPUT_FILE
 
+UNNAMED_SECTIONS = {
+    'Steps': lambda storage: storage.steps,
+    'Move Changes': lambda storage: storage.movechanges,
+    'SampleSets': lambda storage: storage.samplesets,
+    'Trajectories': lambda storage: storage.trajectories,
+    'Snapshots': lambda storage: storage.snapshots
+}
+
 @click.command(
     'contents',
     short_help="list named objects from an OPS .nc file",
 )
 @INPUT_FILE.clicked(required=True)
-def contents(input_file):
+@click.option('--table', type=str, required=False,
+              help="table to show results from")
+def contents(input_file, table):
     """List the names of named objects in an OPS .nc file.
 
     This is particularly useful when getting ready to use one of simulation
     scripts (i.e., to identify exactly how a state or engine is named.)
     """
     storage = INPUT_FILE.get(input_file)
     print(storage)
+    if table is None:
+        report_all_tables(storage)
+    else:
+        table_attr = table.lower()
+        try:
+            store = getattr(storage, table_attr)
+        except AttributeError:
+            print("This needs to raise a good error; bad table name")
+        else:
+            if table_attr in UNNAMED_SECTIONS:
+                print(get_unnamed_section_string(table_attr, store))
+            else:
+                print(get_section_string_nameable(table_attr, store,
+                                                  _get_named_namedobj))
+
+def report_all_tables(storage):
     store_section_mapping = {
         'CVs': storage.cvs, 'Volumes': storage.volumes,
         'Engines': storage.engines, 'Networks': storage.networks,
@@ -26,12 +52,8 @@ def contents(input_file):
     print(get_section_string_nameable('Tags', storage.tags, _get_named_tags))
 
     print("\nData Objects:")
-    unnamed_sections = {
-        'Steps': storage.steps, 'Move Changes': storage.movechanges,
-        'SampleSets': storage.samplesets,
-        'Trajectories': storage.trajectories, 'Snapshots': storage.snapshots
-    }
-    for section, store in unnamed_sections.items():
+    for section, store_func in UNNAMED_SECTIONS.items():
+        store = store_func(storage)
         print(get_unnamed_section_string(section, store))
 
 def _item_or_items(count):