Dropped sql.compose

Use a SQL % operator instead.

2 files changed, 48 insertions, 37 deletions

diff --git a/lib/sql.py b/lib/sql.py
index 287a1f7..b465cbe 100644
--- a/lib/sql.py
+++ b/lib/sql.py
@@ -145,6 +145,20 @@ class SQL(Composable):
     """
     A `Composable` representing a snippet of SQL string to be included verbatim.
 
+    `!SQL` supports the ``%`` operator to incorporate variable parts of a query
+    into a template: the operator takes a sequence or mapping of `Composable`
+    (according to the style of the placeholders in the *string*) and returning
+    a `Composed` object.
+
+    Example::
+
+        >>> query = sql.SQL("select %s from %s") % [
+        ...    sql.SQL(', ').join([sql.Identifier('foo'), sql.Identifier('bar')]),
+        ...    sql.Identifier('table')]
+        >>> query.as_string(conn)
+        select "foo", "bar" from "table"'
+
+
     .. automethod:: join
     """
     def __init__(self, string):
@@ -155,6 +169,9 @@ class SQL(Composable):
     def __repr__(self):
         return "sql.SQL(%r)" % (self._wrapped,)
 
+    def __mod__(self, args):
+        return _compose(self._wrapped, args)
+
     def as_string(self, conn_or_curs):
         return self._wrapped
 
@@ -162,7 +179,7 @@ class SQL(Composable):
         """
         Join a sequence of `Composable` or a `Composed` and return a `!Composed`.
 
-        Use the object value to separate the *seq* elements.
+        Use the object *string* to separate the *seq* elements.
 
         Example::
 
@@ -215,7 +232,13 @@ class Literal(Composable):
     """
     Represent an SQL value to be included in a query.
 
-    The object follows the normal :ref:`adaptation rules <python-types-adaptation>`
+    Usually you will want to include placeholders in the query and pass values
+    as `~cursor.execute()` arguments. If however you really really need to
+    include a literal value in the query you can use this object.
+
+    The string returned by `!as_string()` follows the normal :ref:`adaptation
+    rules <python-types-adaptation>` for Python objects.
+
     """
     def __init__(self, wrapped):
         self._wrapped = wrapped
@@ -254,13 +277,13 @@ class Placeholder(Composable):
 
     Examples::
 
-        >>> sql.compose("insert into table (%s) values (%s)", [
+        >>> (sql.SQL("insert into table (%s) values (%s)") % [
         ...     sql.SQL(', ').join(map(sql.Identifier, names)),
         ...     sql.SQL(', ').join(sql.Placeholder() * 3)
         ... ]).as_string(conn)
         'insert into table ("foo", "bar", "baz") values (%s, %s, %s)'
 
-        >>> sql.compose("insert into table (%s) values (%s)", [
+        >>> (sql.SQL("insert into table (%s) values (%s)") % [
         ...     sql.SQL(', ').join(map(sql.Identifier, names)),
         ...     sql.SQL(', ').join(map(sql.Placeholder, names))
         ... ]).as_string(conn)
@@ -297,7 +320,7 @@ re_compose = re.compile("""
     """, re.VERBOSE)
 
 
-def compose(sql, args=None):
+def _compose(sql, args=None):
     """
     Merge an SQL string with some variable parts.
 
@@ -313,17 +336,6 @@ def compose(sql, args=None):
 
     The value returned is a `Composed` instance obtained replacing the
     arguments to the query placeholders.
-
-    Example::
-
-        >>> query = sql.compose(
-        ...    "select %s from %s", [
-        ...        sql.SQL(', ').join(
-        ...            [sql.Identifier('foo'), sql.Identifier('bar')]),
-        ...        sql.Identifier('table')])
-        >>> query.as_string(conn)
-        select "foo", "bar" from "table"'
-
     """
     if args is None:
         args = ()
diff --git a/tests/test_sql.py b/tests/test_sql.py
index 7fe201a..5482ccb 100755
--- a/tests/test_sql.py
+++ b/tests/test_sql.py
@@ -30,61 +30,60 @@ from psycopg2 import sql
 
 class ComposeTests(ConnectingTestCase):
     def test_pos(self):
-        s = sql.compose("select %s from %s",
-            (sql.Identifier('field'), sql.Identifier('table')))
+        s = sql.SQL("select %s from %s") \
+            % (sql.Identifier('field'), sql.Identifier('table'))
         s1 = s.as_string(self.conn)
         self.assert_(isinstance(s1, str))
         self.assertEqual(s1, 'select "field" from "table"')
 
     def test_dict(self):
-        s = sql.compose("select %(f)s from %(t)s",
-            {'f': sql.Identifier('field'), 't': sql.Identifier('table')})
+        s = sql.SQL("select %(f)s from %(t)s") \
+            % {'f': sql.Identifier('field'), 't': sql.Identifier('table')}
         s1 = s.as_string(self.conn)
         self.assert_(isinstance(s1, str))
         self.assertEqual(s1, 'select "field" from "table"')
 
     def test_unicode(self):
-        s = sql.compose(u"select %s from %s",
-            (sql.Identifier(u'field'), sql.Identifier('table')))
+        s = sql.SQL(u"select %s from %s") \
+            % (sql.Identifier(u'field'), sql.Identifier('table'))
         s1 = s.as_string(self.conn)
         self.assert_(isinstance(s1, unicode))
         self.assertEqual(s1, u'select "field" from "table"')
 
     def test_compose_literal(self):
-        s = sql.compose("select %s;", [sql.Literal(dt.date(2016, 12, 31))])
+        s = sql.SQL("select %s;") % [sql.Literal(dt.date(2016, 12, 31))]
         s1 = s.as_string(self.conn)
         self.assertEqual(s1, "select '2016-12-31'::date;")
 
     def test_compose_empty(self):
-        s = sql.compose("select foo;")
+        s = sql.SQL("select foo;") % ()
         s1 = s.as_string(self.conn)
         self.assertEqual(s1, "select foo;")
 
     def test_percent_escape(self):
-        s = sql.compose("42 %% %s", [sql.Literal(7)])
+        s = sql.SQL("42 %% %s") % [sql.Literal(7)]
         s1 = s.as_string(self.conn)
         self.assertEqual(s1, "42 % 7")
 
-        s = sql.compose("42 %% 7")
+        s = sql.SQL("42 %% 7") % []
         s1 = s.as_string(self.conn)
         self.assertEqual(s1, "42 % 7")
 
     def test_compose_badnargs(self):
-        self.assertRaises(ValueError, sql.compose, "select foo;", [10])
-        self.assertRaises(ValueError, sql.compose, "select %s;")
-        self.assertRaises(ValueError, sql.compose, "select %s;", [])
-        self.assertRaises(ValueError, sql.compose, "select %s;", [10, 20])
+        self.assertRaises(ValueError, sql.SQL("select foo;").__mod__, [10])
+        self.assertRaises(ValueError, sql.SQL("select %s;").__mod__, [])
+        self.assertRaises(ValueError, sql.SQL("select %s;").__mod__, [10, 20])
 
     def test_compose_bad_args_type(self):
-        self.assertRaises(TypeError, sql.compose, "select %s;", {'a': 10})
-        self.assertRaises(TypeError, sql.compose, "select %(x)s;", [10])
+        self.assertRaises(TypeError, sql.SQL("select %s;").__mod__, {'a': 10})
+        self.assertRaises(TypeError, sql.SQL("select %(x)s;").__mod__, [10])
 
     def test_must_be_adaptable(self):
         class Foo(object):
             pass
 
         self.assertRaises(TypeError,
-            sql.compose, "select %s;", [Foo()])
+            sql.SQL("select %s;").__mod__, [Foo()])
 
     def test_execute(self):
         cur = self.conn.cursor()
@@ -94,11 +93,11 @@ class ComposeTests(ConnectingTestCase):
                 foo text, bar text, "ba'z" text)
             """)
         cur.execute(
-            sql.compose("insert into %s (id, %s) values (%%s, %s)", [
+            sql.SQL("insert into %s (id, %s) values (%%s, %s)") % [
                 sql.Identifier('test_compose'),
                 sql.SQL(', ').join(map(sql.Identifier, ['foo', 'bar', "ba'z"])),
                 (sql.PH() * 3).join(', '),
-            ]),
+            ],
             (10, 'a', 'b', 'c'))
 
         cur.execute("select * from test_compose")
@@ -112,11 +111,11 @@ class ComposeTests(ConnectingTestCase):
                 foo text, bar text, "ba'z" text)
             """)
         cur.executemany(
-            sql.compose("insert into %s (id, %s) values (%%s, %s)", [
+            sql.SQL("insert into %s (id, %s) values (%%s, %s)") % [
                 sql.Identifier('test_compose'),
                 sql.SQL(', ').join(map(sql.Identifier, ['foo', 'bar', "ba'z"])),
                 (sql.PH() * 3).join(', '),
-            ]),
+            ],
             [(10, 'a', 'b', 'c'), (20, 'd', 'e', 'f')])
 
         cur.execute("select * from test_compose")