add function to convert int to letters

git-svn-id: https://svn.erp5.org/repos/public/erp5/trunk@24638 20353a03-c40f-0410-a6d1-a30d3c3de9de

product/ERP5Type/Utils.py

@@ -259,6 +259,15 @@ def getPath(object_or_path, **kw):
     return path.split('/')
   return path
 
+def int2letters(i):
+  """
+  Convert an integer to letters, to generate spreadsheet column id
+  A, B, C ..., Z, AA, AB, ..., AZ, BA, ..., ZZ, AAA ...
+  """
+  if i < 26:
+    return (chr(i + ord('A')))
+  d, m = divmod(i, 26)
+  return int2letter(d - 1) + int2letter(m)
 
 #####################################################
 # Globals initialization

product/ERP5Type/__init__.py

@@ -107,7 +107,8 @@ from AccessControl.SecurityInfo import ModuleSecurityInfo
 allow_module('Products.ERP5Type.Cache')
 ModuleSecurityInfo('Products.ERP5Type.Utils').declarePublic(
     'sortValueList', 'convertToUpperCase', 'UpperCase',
-    'convertToMixedCase', 'cartesianProduct', 'sleep', 'getCommonTimeZoneList')
+    'convertToMixedCase', 'cartesianProduct', 'sleep', 'getCommonTimeZoneList',
+    'int2letters',)
 
 allow_module('Products.ERP5Type.Message')
 ModuleSecurityInfo('Products.ERP5Type.Message').declarePublic('translateString')