From 93fab0bb069e81ab63781027512eccb81bea3b35 Mon Sep 17 00:00:00 2001
From: "K.R. Zentner" <krzentner@gmail.com>
Date: Mon, 4 Nov 2019 20:27:26 -0800
Subject: [PATCH] Add dots to alternating tabular lines

Tables with keys of varying lengths are hard to read, since some of the
key names end up far from their values. This change adds a sequence of
dots on all odd lines, so that lines are easier to match up with their
keys.
---
 setup.py                           |  1 +
 src/dowel/tabular_input.py         | 24 ++++++++++++++++++++----
 tests/dowel/test_simple_outputs.py | 30 ++++++++++++++++++++++++++++++
 3 files changed, 51 insertions(+), 4 deletions(-)

diff --git a/setup.py b/setup.py
index 45d2f1af..876c9abd 100644
--- a/setup.py
+++ b/setup.py
@@ -10,6 +10,7 @@
     'scipy',
     'tabulate',
     'tensorboardX',
+    'wcwidth',
 ]
 
 extras = dict()
diff --git a/src/dowel/tabular_input.py b/src/dowel/tabular_input.py
index 43ca6625..5f86433e 100644
--- a/src/dowel/tabular_input.py
+++ b/src/dowel/tabular_input.py
@@ -1,6 +1,7 @@
 """A `dowel.logger` input for tabular (key-value) data."""
 import contextlib
 import warnings
+import wcwidth
 
 import numpy as np
 import tabulate
@@ -24,8 +25,23 @@ def __init__(self):
 
     def __str__(self):
         """Return a string representation of the table for the logger."""
-        return tabulate.tabulate(
-            sorted(self.as_primitive_dict.items(), key=lambda x: x[0]))
+        # Sort first, then pad.
+        lines = sorted(self.as_primitive_dict.items(), key=lambda x: x[0])
+        key_widths = [wcwidth.wcswidth(key) for key, value in lines]
+        max_key_width = max(key_widths, default=0)
+        padded_keys = []
+        for line, (key, value) in enumerate(lines):
+            padded_key = key
+            if line % 2 == 1:
+                key_width = wcwidth.wcswidth(key)
+                if key_width % 2 == 1 and key_width < max_key_width:
+                    padded_key += ' '
+                    key_width += 1
+                pad_width = (max_key_width - key_width) // 2
+                padded_key += ' .' * pad_width
+            padded_keys.append(padded_key)
+        values = [value for key, value in lines]
+        return tabulate.tabulate(zip(padded_keys, values))
 
     def record(self, key, val):
         """Save key/value entries for the table.
@@ -55,11 +71,11 @@ def record_misc_stat(self, key, values, placement='back'):
         :param placement: Whether to put the prefix in front or in the back.
         """
         if placement == 'front':
-            front = ""
+            front = ''
             back = key
         else:
             front = key
-            back = ""
+            back = ''
         if values:
             self.record(front + 'Average' + back, np.average(values))
             self.record(front + 'Std' + back, np.std(values))
diff --git a/tests/dowel/test_simple_outputs.py b/tests/dowel/test_simple_outputs.py
index 04b6b11d..0797ec0a 100644
--- a/tests/dowel/test_simple_outputs.py
+++ b/tests/dowel/test_simple_outputs.py
@@ -125,6 +125,36 @@ def test_record_tabular(self, mock_datetime):
         self.str_out.seek(0)
         assert self.str_out.read() == tab
 
+    def test_record_tabular_line_markers(self, mock_datetime):
+        fake_timestamp(mock_datetime)
+
+        self.tabular.record('a', 100)
+        self.tabular.record('bbbbbbb', 55)
+        self.tabular.record('ccccc', 55)
+        self.tabular.record('d', 55)
+        self.tabular.record('ee', 55)
+        self.tabular.record('ff', 55)
+
+        with redirect_stdout(self.str_out):
+            self.std_output.record(self.tabular)
+
+        self.std_output.dump()
+
+        tab = (
+            '-------  ---\n'
+            'a        100\n'
+            'bbbbbbb   55\n'
+            'ccccc     55\n'
+            'd  . .    55\n'
+            'ee        55\n'
+            'ff . .    55\n'
+            '-------  ---\n'
+        )  # yapf: disable
+        self.str_out.seek(0)
+        output = self.str_out.read()
+        print(output)
+        assert output == tab
+
     def test_record_with_timestamp(self, mock_datetime):
         fake_timestamp(mock_datetime)