#308: allow "double" as alias for "pair" in index entries.

sphinx/directives/other.py

@@ -235,7 +235,7 @@ class Index(Directive):
     option_spec = {}
 
     indextypes = [
-        'single', 'pair', 'triple',
+        'single', 'pair', 'double', 'triple',
     ]
 
     def run(self):
@@ -259,6 +259,8 @@ class Index(Directive):
                 for type in self.indextypes:
                     if entry.startswith(type+':'):
                         value = entry[len(type)+1:].strip()
+                        if type == 'double':
+                            type = 'pair'
                         ne.append((type, value, targetid, value))
                         break
                 # shorthand notation for single entries

tests/root/markup.txt

@@ -162,6 +162,7 @@ Index markup
 .. index::
    single: entry
    pair: entry; pair
+   double: entry; double
    triple: index; entry; triple
    keyword: with