Format IP lists as tables

This commit changes the formatting of IP address lists from paragraph to
table markup. The commit fixes PEP8 violations.

jandd/sphinxext/ip.py

@@ -8,7 +8,6 @@
     :copyright: Copyright (c) 2016 Jan Dittberner
     :license: GPLv3+, see COPYING file for details.
 """
-__version__ = '0.2.0'
 
 import re
 
@@ -24,15 +23,20 @@ from sphinx.locale import l_
 from sphinx.roles import XRefRole
 from sphinx.util.nodes import make_refnode
 
+__version__ = '0.2.0'
+
 
 def ip_object_anchor(typ, path):
     path = re.sub(r'[.:/]', '-', path)
     return typ.lower() + '-' + path
 
 
-class ip_node(nodes.Inline, nodes.TextElement): pass
+class ip_node(nodes.Inline, nodes.TextElement):
+    pass
 
-class ip_range(nodes.General, nodes.Element): pass
+
+class ip_range(nodes.General, nodes.Element):
+    pass
 
 
 class IPXRefRole(XRefRole):
@@ -42,7 +46,7 @@ class IPXRefRole(XRefRole):
     def __init__(self, method, index_type, **kwargs):
         self.method = method
         self.index_type = index_type
-        innernodeclass=None
+        innernodeclass = None
         if method in ('v4', 'v6'):
             innernodeclass = ip_node
         super(IPXRefRole, self).__init__(
@@ -234,19 +238,46 @@ def sort_ip_info(item):
     return Network(item['ip']).ip
 
 
+def create_table_row(rowdata):
+    row = nodes.row()
+    for cell in rowdata:
+        entry = nodes.entry()
+        row += entry
+        entry += cell
+    return row
+
+
 def process_ip_nodes(app, doctree, fromdocname):
     env = app.builder.env
     domaindata = env.domaindata[IPDomain.name]
 
+    header = (l_('IP address'), l_('Used by'))
+    colwidths = (1, 3)
+
     for node in doctree.traverse(ip_range):
         content = []
         net = Network(node['rangespec'])
-        for ip_info in sorted(domaindata['ips'], key=sort_ip_info):
-            if ip_info['ip'] in net:
+        ips = [ip_info for ip_info in
+               sorted(domaindata['ips'], key=sort_ip_info)
+               if ip_info['ip'] in net]
+        if ips:
+            table = nodes.table()
+            tgroup = nodes.tgroup(cols=len(header))
+            table += tgroup
+            for colwidth in colwidths:
+                tgroup += nodes.colspec(colwidth=colwidth)
+            thead = nodes.thead()
+            tgroup += thead
+            thead += create_table_row([
+                nodes.paragraph(text=label) for label in header])
+            tbody = nodes.tbody()
+            tgroup += tbody
+            for ip_info in ips:
                 para = nodes.paragraph()
                 para += nodes.literal('', ip_info['ip'])
                 ids = ip_object_anchor(ip_info['typ'], ip_info['ip'])
                 para['ids'].append(ids)
+
                 domaindata[ip_info['typ']][ids] = (fromdocname, '')
                 newnode = nodes.reference('', '', internal=True)
                 try:
@@ -257,8 +288,12 @@ def process_ip_nodes(app, doctree, fromdocname):
                 title = env.titles[ip_info['docname']]
                 innernode = nodes.Text(title.astext())
                 newnode.append(innernode)
-                para += nodes.Text(" in ")
-                para += newnode
+                refnode = nodes.paragraph()
+                refnode.append(newnode)
+                tbody += create_table_row([para, refnode])
+            content.append(table)
+        else:
+            para = nodes.paragraph(l_('No IP addresses in this range'))
             content.append(para)
         node.replace_self(content)