Add sql_pairing tool

issue9606
review328091002

CHANGELOG

@@ -1,3 +1,4 @@
+* Add sql_pairing tool
 * Add format_datetime to Report
 * Allow sharing view searches
 * Allow overriding digits in Lang.currency and Report.format_currency

doc/ref/tools/misc.rst

@@ -8,3 +8,7 @@ Miscellaneous
 .. method:: resolve(name)
 
 Resolve a dotted name to a global object.
+
+.. method:: sql_pairing(x, y)
+
+Return an SQL expression that pairs SQL integers x and y.

trytond/tools/__init__.py

@@ -9,14 +9,14 @@ from .misc import (
     file_open, get_smtp_server, reduce_ids, reduce_domain,
     grouped_slice, is_instance_method, resolve, strip_wildcard,
     lstrip_wildcard, rstrip_wildcard, slugify, sortable_values,
-    escape_wildcard)
+    escape_wildcard, sql_pairing)
 from .decimal_ import decistmt
 
 __all__ = ['file_open', 'get_smtp_server', 'reduce_ids',
     'reduce_domain', 'grouped_slice', 'is_instance_method', 'resolve',
     'strip_wildcard', 'lstrip_wildcard', 'rstrip_wildcard', 'slugify',
     'decistmt', 'ClassProperty', 'cursor_dict', 'cached_property',
-    'sortable_values', 'escape_wildcard']
+    'sortable_values', 'escape_wildcard', 'sql_pairing']
 
 
 class ClassProperty(property):

trytond/tools/misc.py

@@ -17,6 +17,7 @@ from functools import wraps
 from itertools import islice
 
 from sql import Literal
+from sql.conditionals import Case
 from sql.operators import Or
 
 from trytond.const import OPERATORS
@@ -241,3 +242,11 @@ def sortable_values(func):
             result[i] = (name, value is None, value)
         return result
     return wrapper
+
+
+def sql_pairing(x, y):
+    """Return SQL expression to pair x and y
+    Pairing function from http://szudzik.com/ElegantPairing.pdf"""
+    return Case(
+        (x < y, (y * y) + x),
+        else_=(x * x) + x + y)