Compile plural strings to android <plurals> elem

grit/format/android_xml.py

Index: grit/format/android_xml.py
diff --git a/grit/format/android_xml.py b/grit/format/android_xml.py
index d960bf49ddb8f009575b36f3a146cd25edbef8f8..5b2c080f8c482cc4619e5de61eb4ee36afc56dfb 100644
--- a/grit/format/android_xml.py
+++ b/grit/format/android_xml.py
@@ -58,6 +58,7 @@ would generate
 """
 
 import os
+import re
 import types
 import xml.sax.saxutils
 
@@ -96,6 +97,13 @@ _SIMPLE_TEMPLATE = u'<string name="%s">%s</string>\n'
 _PRODUCT_TEMPLATE = u'<string name="%s" product="%s">%s</string>\n'
 
 
+# Some strings have a plural equivalent
+_PLURALS_TEMPLATE = '<plurals name="%s">\n%s</plurals>\n'
+_PLURALS_ITEM_TEMPLATE = ' <item quantity="%s">%s</item>\n'
+_PLURALS_PATTERN = lazy_re.compile(r'\{[A-Z_]+,\s*plural,(?P<items>.*)\}$', flags=re.S)
+_PLURALS_ITEM_PATTERN = lazy_re.compile(r'(?P<quantity>\S+)\s*\{(?P<value>.*?)\}')
+
+
 def Format(root, lang='en', output_dir='.'):
   yield ('<?xml version="1.0" encoding="utf-8"?>\n'
           '<resources '
@@ -131,6 +139,51 @@ def ShouldOutputNode(node, tagged_only):
           (not tagged_only or _EMIT_TAG in node.formatter_data))
 
 
+def _FormatPluralMessage(message):
+  """Compile ICU plural syntax to the body of an Android <plurals> element.

[newt (away), 2015/08/04 03:14:26]

nit: "Compiles"

[conleyo, 2015/08/04 16:53:02]

Done.

+    
+  1. In a .grd file, we can write a plural string like this:
+    
+    <message name="IDS_THINGS">
+      {NUM_THINGS, plural,
+      =1 {1 thing}
+      other {# things}}
+    </message>
+    
+  2. The Android equivalent looks like this:
+    
+    <plurals name="things">
+      <item quantity="one">1 thing</item>
+      <item quantity="other">%d things</item>
+    </plurals>
+
+  This method takes the body of (1) and converts it to the body of (2).
+    
+  If the message is *not* a plural string, this function returns `None`.
+  If the message includes quantities without an equivalent format in Android,
+  it raises an exception.
+  """
+  ret = {}
+  plural_match = _PLURALS_PATTERN.match(message)
+  if not plural_match:
+    return None
+  body_in = plural_match.group('items').strip()
+  body_out = u''

[newt (away), 2015/08/04 03:14:26]

A better idiom for concatenating strings in python (to avoid quadratic
behavior):

   out_lines = ''
   ...
     out_lines.append(...)

   return '\n'.join(out_lines)

[conleyo, 2015/08/04 16:53:02]

Done.

+  for item_match in _PLURALS_ITEM_PATTERN.finditer(body_in):
+    quantity = item_match.group('quantity')
+    value = item_match.group('value').replace('#', '%d')
+    if quantity == '=0':
+      body_out += _PLURALS_ITEM_TEMPLATE % ('zero', value)
+    elif quantity == '=1':
+      body_out += _PLURALS_ITEM_TEMPLATE % ('one', value)
+    elif quantity == 'other':
+      body_out += _PLURALS_ITEM_TEMPLATE % ('other', value)
+    else:

[newt (away), 2015/08/04 03:14:26]

Why not handle "=2", "few" and "many"?

[conleyo, 2015/08/04 16:53:02]

Done.

+      raise Exception('Unsupported plural quantity for android '
+                      'strings.xml: %s' % quantity)
+  return body_out
+
+
 def _FormatMessage(item, lang):
   """Writes out a single string as a <resource/> element."""
 
@@ -138,6 +191,7 @@ def _FormatMessage(item, lang):
   # Replace < > & with &lt; &gt; &amp; to ensure we generate valid XML and
   # replace ' " with \' \" to conform to Android's string formatting rules.
   value = xml.sax.saxutils.escape(value, {"'": "\\'", '"': '\\"'})
+  plurals = _FormatPluralMessage(value)
   # Wrap the string in double quotes to preserve whitespace.
   value = '"' + value + '"'
 
@@ -152,7 +206,9 @@ def _FormatMessage(item, lang):
   product = item.formatter_data.get(_PRODUCT_TAG, product)
   name = item.formatter_data.get(_NAME_TAG, name)
 
-  if product:
+  if plurals:
+    return _PLURALS_TEMPLATE % (name, plurals)
+  elif product:
     return _PRODUCT_TEMPLATE % (name, product, value)
   else:
     return _SIMPLE_TEMPLATE % (name, value)