From fd8567037269ac937a6b079c6e00022abfc51149 Mon Sep 17 00:00:00 2001
From: Mike Bayer <mike_mp@zzzcomputing.com>
Date: Wed, 1 Mar 2006 19:43:07 +0000
Subject: [PATCH] postgres leaves parenthesis off functions only for
 no-argument ANSI functions according to a list

---
 CHANGES                              |  3 ++-
 lib/sqlalchemy/databases/postgres.py | 21 +++++++++++++++++----
 2 files changed, 19 insertions(+), 5 deletions(-)

diff --git a/CHANGES b/CHANGES
index f0cd2fbc41..5a749f1310 100644
--- a/CHANGES
+++ b/CHANGES
@@ -25,7 +25,8 @@ check when object attributes are modified or the object is deleted
 - added "convert_unicode" flag to SQLEngine, will treat all String/CHAR types
 as Unicode types, with raw-byte/utf-8 translation on the bind parameter and 
 result set side.
-
+- postgres maintains a list of ANSI functions that must have no parenthesis so
+function calls with no arguments work consistently
 0.1.2
 - fixed a recursive call in schema that was somehow running 994 times then returning
 normally.  broke nothing, slowed down everything.  thanks to jpellerin for finding this.
diff --git a/lib/sqlalchemy/databases/postgres.py b/lib/sqlalchemy/databases/postgres.py
index 67e3d5cf57..13714ba3e6 100644
--- a/lib/sqlalchemy/databases/postgres.py
+++ b/lib/sqlalchemy/databases/postgres.py
@@ -6,6 +6,7 @@
 
 import sys, StringIO, string, types, re
 
+import sqlalchemy.util as util
 import sqlalchemy.sql as sql
 import sqlalchemy.engine as engine
 import sqlalchemy.schema as schema
@@ -101,7 +102,18 @@ class PGBinary(sqltypes.Binary):
 class PGBoolean(sqltypes.Boolean):
     def get_col_spec(self):
         return "BOOLEAN"
-        
+
+ANSI_FUNCS = util.HashSet([
+'CURRENT_TIME',
+'CURRENT_TIMESTAMP',
+'CURRENT_DATE',
+'LOCAL_TIME',
+'LOCAL_TIMESTAMP',
+'CURRENT_USER',
+'SESSION_USER',
+'USER'
+])
+
 pg2_colspecs = {
     sqltypes.Integer : PGInteger,
     sqltypes.Smallinteger : PGSmallInteger,
@@ -270,10 +282,11 @@ class PGSQLEngine(ansisql.ANSISQLEngine):
 class PGCompiler(ansisql.ANSICompiler):
 
     def visit_function(self, func):
-        if len(func.clauses):
-            super(PGCompiler, self).visit_function(func)
-        else:
+        # PG has a bunch of funcs that explicitly need no parenthesis
+        if func.name.upper() in ANSI_FUNCS and not len(func.clauses):
             self.strings[func] = func.name
+        else:
+            super(PGCompiler, self).visit_function(func)
         
     def visit_insert_column(self, column):
         # Postgres advises against OID usage and turns it off in 8.1,
-- 
2.47.2