From cac76582053ef8ea07df65fed0757f352da23705 Mon Sep 17 00:00:00 2001
From: Peter Eisentraut <peter_e@gmx.net>
Date: Sun, 26 Apr 2015 10:33:14 -0400
Subject: Add transforms feature
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This provides a mechanism for specifying conversions between SQL data
types and procedural languages.  As examples, there are transforms
for hstore and ltree for PL/Perl and PL/Python.

reviews by Pavel Stěhule and Andres Freund
---
 contrib/ltree_plpython/sql/ltree_plpython.sql | 37 +++++++++++++++++++++++++++
 1 file changed, 37 insertions(+)
 create mode 100644 contrib/ltree_plpython/sql/ltree_plpython.sql

(limited to 'contrib/ltree_plpython/sql/ltree_plpython.sql')

diff --git a/contrib/ltree_plpython/sql/ltree_plpython.sql b/contrib/ltree_plpython/sql/ltree_plpython.sql
new file mode 100644
index 00000000000..f08ff6a3f06
--- /dev/null
+++ b/contrib/ltree_plpython/sql/ltree_plpython.sql
@@ -0,0 +1,37 @@
+CREATE EXTENSION plpython2u;
+CREATE EXTENSION ltree_plpython2u;
+
+
+CREATE FUNCTION test1(val ltree) RETURNS int
+LANGUAGE plpythonu
+TRANSFORM FOR TYPE ltree
+AS $$
+plpy.info(repr(val))
+return len(val)
+$$;
+
+SELECT test1('aa.bb.cc'::ltree);
+
+
+CREATE FUNCTION test1n(val ltree) RETURNS int
+LANGUAGE plpython2u
+TRANSFORM FOR TYPE ltree
+AS $$
+plpy.info(repr(val))
+return len(val)
+$$;
+
+SELECT test1n('aa.bb.cc'::ltree);
+
+
+CREATE FUNCTION test2() RETURNS ltree
+LANGUAGE plpythonu
+TRANSFORM FOR TYPE ltree
+AS $$
+return ['foo', 'bar', 'baz']
+$$;
+
+-- plpython to ltree is not yet implemented, so this will fail,
+-- because it will try to parse the Python list as an ltree input
+-- string.
+SELECT test2();
-- 
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