Improve parsetree representation of special functions such as CURRENT_DATE.

We implement a dozen or so parameterless functions that the SQL standard
defines special syntax for.  Up to now, that was done by converting them
into more or less ad-hoc constructs such as "'now'::text::date".  That's
messy for multiple reasons: it exposes what should be implementation
details to users, and performance is worse than it needs to be in several
cases.  To improve matters, invent a new expression node type
SQLValueFunction that can represent any of these parameterless functions.

Bump catversion because this changes stored parsetrees for rules.

Discussion: <30058.1463091294@sss.pgh.pa.us>

4 files changed, 51 insertions, 51 deletions

diff --git a/src/test/regress/expected/rowsecurity.out b/src/test/regress/expected/rowsecurity.out
index c15bf958a51..abfee92f4de 100644
--- a/src/test/regress/expected/rowsecurity.out
+++ b/src/test/regress/expected/rowsecurity.out
@@ -182,7 +182,7 @@ EXPLAIN (COSTS OFF) SELECT * FROM document WHERE f_leak(dtitle);
          Filter: (dlevel <= $0)
          InitPlan 1 (returns $0)
            ->  Index Scan using uaccount_pkey on uaccount
-                 Index Cond: (pguser = "current_user"())
+                 Index Cond: (pguser = CURRENT_USER)
 (7 rows)
 
 EXPLAIN (COSTS OFF) SELECT * FROM document NATURAL JOIN category WHERE f_leak(dtitle);
@@ -198,7 +198,7 @@ EXPLAIN (COSTS OFF) SELECT * FROM document NATURAL JOIN category WHERE f_leak(dt
                      Filter: (dlevel <= $0)
                      InitPlan 1 (returns $0)
                        ->  Index Scan using uaccount_pkey on uaccount
-                             Index Cond: (pguser = "current_user"())
+                             Index Cond: (pguser = CURRENT_USER)
 (11 rows)
 
 -- only owner can change policies
@@ -265,22 +265,22 @@ NOTICE:  f_leak => great manga
 (3 rows)
 
 EXPLAIN (COSTS OFF) SELECT * FROM document WHERE f_leak(dtitle);
-                  QUERY PLAN                  
-----------------------------------------------
+                QUERY PLAN                
+------------------------------------------
  Subquery Scan on document
    Filter: f_leak(document.dtitle)
    ->  Seq Scan on document document_1
-         Filter: (dauthor = "current_user"())
+         Filter: (dauthor = CURRENT_USER)
 (4 rows)
 
 EXPLAIN (COSTS OFF) SELECT * FROM document NATURAL JOIN category WHERE f_leak(dtitle);
-                     QUERY PLAN                     
-----------------------------------------------------
+                    QUERY PLAN                    
+--------------------------------------------------
  Nested Loop
    ->  Subquery Scan on document
          Filter: f_leak(document.dtitle)
          ->  Seq Scan on document document_1
-               Filter: (dauthor = "current_user"())
+               Filter: (dauthor = CURRENT_USER)
    ->  Index Scan using category_pkey on category
          Index Cond: (cid = document.cid)
 (7 rows)
diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out
index c5ff3181a3e..8157324fee1 100644
--- a/src/test/regress/expected/rules.out
+++ b/src/test/regress/expected/rules.out
@@ -2269,14 +2269,14 @@ pg_settings|pg_settings_u|CREATE RULE pg_settings_u AS
    WHERE (new.name = old.name) DO  SELECT set_config(old.name, new.setting, false) AS set_config;
 rtest_emp|rtest_emp_del|CREATE RULE rtest_emp_del AS
     ON DELETE TO rtest_emp DO  INSERT INTO rtest_emplog (ename, who, action, newsal, oldsal)
-  VALUES (old.ename, "current_user"(), 'fired'::bpchar, '$0.00'::money, old.salary);
+  VALUES (old.ename, CURRENT_USER, 'fired'::bpchar, '$0.00'::money, old.salary);
 rtest_emp|rtest_emp_ins|CREATE RULE rtest_emp_ins AS
     ON INSERT TO rtest_emp DO  INSERT INTO rtest_emplog (ename, who, action, newsal, oldsal)
-  VALUES (new.ename, "current_user"(), 'hired'::bpchar, new.salary, '$0.00'::money);
+  VALUES (new.ename, CURRENT_USER, 'hired'::bpchar, new.salary, '$0.00'::money);
 rtest_emp|rtest_emp_upd|CREATE RULE rtest_emp_upd AS
     ON UPDATE TO rtest_emp
    WHERE (new.salary <> old.salary) DO  INSERT INTO rtest_emplog (ename, who, action, newsal, oldsal)
-  VALUES (new.ename, "current_user"(), 'honored'::bpchar, new.salary, old.salary);
+  VALUES (new.ename, CURRENT_USER, 'honored'::bpchar, new.salary, old.salary);
 rtest_nothn1|rtest_nothn_r1|CREATE RULE rtest_nothn_r1 AS
     ON INSERT TO rtest_nothn1
    WHERE ((new.a >= 10) AND (new.a < 20)) DO INSTEAD NOTHING;
diff --git a/src/test/regress/expected/select_views.out b/src/test/regress/expected/select_views.out
index 7f575266c1b..878035332bb 100644
--- a/src/test/regress/expected/select_views.out
+++ b/src/test/regress/expected/select_views.out
@@ -1326,10 +1326,10 @@ NOTICE:  f_leak => hamburger
 (1 row)
 
 EXPLAIN (COSTS OFF) SELECT * FROM my_property_normal WHERE f_leak(passwd);
-                            QUERY PLAN                            
-------------------------------------------------------------------
+                          QUERY PLAN                          
+--------------------------------------------------------------
  Seq Scan on customer
-   Filter: (f_leak(passwd) AND (name = ("current_user"())::text))
+   Filter: (f_leak(passwd) AND (name = (CURRENT_USER)::text))
 (2 rows)
 
 SELECT * FROM my_property_secure WHERE f_leak(passwd);
@@ -1340,12 +1340,12 @@ NOTICE:  f_leak => passwd123
 (1 row)
 
 EXPLAIN (COSTS OFF) SELECT * FROM my_property_secure WHERE f_leak(passwd);
-                    QUERY PLAN                     
----------------------------------------------------
+                  QUERY PLAN                   
+-----------------------------------------------
  Subquery Scan on my_property_secure
    Filter: f_leak(my_property_secure.passwd)
    ->  Seq Scan on customer
-         Filter: (name = ("current_user"())::text)
+         Filter: (name = (CURRENT_USER)::text)
 (4 rows)
 
 --
@@ -1367,10 +1367,10 @@ NOTICE:  f_leak => hamburger
 
 EXPLAIN (COSTS OFF) SELECT * FROM my_property_normal v
 		WHERE f_leak('passwd') AND f_leak(passwd);
-                                         QUERY PLAN                                          
----------------------------------------------------------------------------------------------
+                                       QUERY PLAN                                        
+-----------------------------------------------------------------------------------------
  Seq Scan on customer
-   Filter: (f_leak('passwd'::text) AND f_leak(passwd) AND (name = ("current_user"())::text))
+   Filter: (f_leak('passwd'::text) AND f_leak(passwd) AND (name = (CURRENT_USER)::text))
 (2 rows)
 
 SELECT * FROM my_property_secure v
@@ -1386,12 +1386,12 @@ NOTICE:  f_leak => passwd
 
 EXPLAIN (COSTS OFF) SELECT * FROM my_property_secure v
 		WHERE f_leak('passwd') AND f_leak(passwd);
-                                   QUERY PLAN                                   
---------------------------------------------------------------------------------
+                                 QUERY PLAN                                 
+----------------------------------------------------------------------------
  Subquery Scan on v
    Filter: f_leak(v.passwd)
    ->  Seq Scan on customer
-         Filter: (f_leak('passwd'::text) AND (name = ("current_user"())::text))
+         Filter: (f_leak('passwd'::text) AND (name = (CURRENT_USER)::text))
 (4 rows)
 
 --
@@ -1409,15 +1409,15 @@ NOTICE:  f_leak => 9801-2345-6789-0123
 (1 row)
 
 EXPLAIN (COSTS OFF) SELECT * FROM my_credit_card_normal WHERE f_leak(cnum);
-                       QUERY PLAN                        
----------------------------------------------------------
+                     QUERY PLAN                      
+-----------------------------------------------------
  Hash Join
    Hash Cond: (r.cid = l.cid)
    ->  Seq Scan on credit_card r
          Filter: f_leak(cnum)
    ->  Hash
          ->  Seq Scan on customer l
-               Filter: (name = ("current_user"())::text)
+               Filter: (name = (CURRENT_USER)::text)
 (7 rows)
 
 SELECT * FROM my_credit_card_secure WHERE f_leak(cnum);
@@ -1428,8 +1428,8 @@ NOTICE:  f_leak => 1111-2222-3333-4444
 (1 row)
 
 EXPLAIN (COSTS OFF) SELECT * FROM my_credit_card_secure WHERE f_leak(cnum);
-                          QUERY PLAN                           
----------------------------------------------------------------
+                        QUERY PLAN                         
+-----------------------------------------------------------
  Subquery Scan on my_credit_card_secure
    Filter: f_leak(my_credit_card_secure.cnum)
    ->  Hash Join
@@ -1437,7 +1437,7 @@ EXPLAIN (COSTS OFF) SELECT * FROM my_credit_card_secure WHERE f_leak(cnum);
          ->  Seq Scan on credit_card r
          ->  Hash
                ->  Seq Scan on customer l
-                     Filter: (name = ("current_user"())::text)
+                     Filter: (name = (CURRENT_USER)::text)
 (8 rows)
 
 --
@@ -1471,7 +1471,7 @@ EXPLAIN (COSTS OFF) SELECT * FROM my_credit_card_usage_normal
                      ->  Seq Scan on credit_card r_1
                      ->  Hash
                            ->  Seq Scan on customer l_1
-                                 Filter: (name = ("current_user"())::text)
+                                 Filter: (name = (CURRENT_USER)::text)
 (13 rows)
 
 SELECT * FROM my_credit_card_usage_secure
@@ -1502,7 +1502,7 @@ EXPLAIN (COSTS OFF) SELECT * FROM my_credit_card_usage_secure
                      ->  Seq Scan on credit_card r_1
                      ->  Hash
                            ->  Seq Scan on customer l
-                                 Filter: (name = ("current_user"())::text)
+                                 Filter: (name = (CURRENT_USER)::text)
 (13 rows)
 
 --
diff --git a/src/test/regress/expected/select_views_1.out b/src/test/regress/expected/select_views_1.out
index 5275ef0b2de..1a05c6ccbd5 100644
--- a/src/test/regress/expected/select_views_1.out
+++ b/src/test/regress/expected/select_views_1.out
@@ -1326,10 +1326,10 @@ NOTICE:  f_leak => hamburger
 (1 row)
 
 EXPLAIN (COSTS OFF) SELECT * FROM my_property_normal WHERE f_leak(passwd);
-                            QUERY PLAN                            
-------------------------------------------------------------------
+                          QUERY PLAN                          
+--------------------------------------------------------------
  Seq Scan on customer
-   Filter: (f_leak(passwd) AND (name = ("current_user"())::text))
+   Filter: (f_leak(passwd) AND (name = (CURRENT_USER)::text))
 (2 rows)
 
 SELECT * FROM my_property_secure WHERE f_leak(passwd);
@@ -1340,12 +1340,12 @@ NOTICE:  f_leak => passwd123
 (1 row)
 
 EXPLAIN (COSTS OFF) SELECT * FROM my_property_secure WHERE f_leak(passwd);
-                    QUERY PLAN                     
----------------------------------------------------
+                  QUERY PLAN                   
+-----------------------------------------------
  Subquery Scan on my_property_secure
    Filter: f_leak(my_property_secure.passwd)
    ->  Seq Scan on customer
-         Filter: (name = ("current_user"())::text)
+         Filter: (name = (CURRENT_USER)::text)
 (4 rows)
 
 --
@@ -1367,10 +1367,10 @@ NOTICE:  f_leak => hamburger
 
 EXPLAIN (COSTS OFF) SELECT * FROM my_property_normal v
 		WHERE f_leak('passwd') AND f_leak(passwd);
-                                         QUERY PLAN                                          
----------------------------------------------------------------------------------------------
+                                       QUERY PLAN                                        
+-----------------------------------------------------------------------------------------
  Seq Scan on customer
-   Filter: (f_leak('passwd'::text) AND f_leak(passwd) AND (name = ("current_user"())::text))
+   Filter: (f_leak('passwd'::text) AND f_leak(passwd) AND (name = (CURRENT_USER)::text))
 (2 rows)
 
 SELECT * FROM my_property_secure v
@@ -1386,12 +1386,12 @@ NOTICE:  f_leak => passwd
 
 EXPLAIN (COSTS OFF) SELECT * FROM my_property_secure v
 		WHERE f_leak('passwd') AND f_leak(passwd);
-                                   QUERY PLAN                                   
---------------------------------------------------------------------------------
+                                 QUERY PLAN                                 
+----------------------------------------------------------------------------
  Subquery Scan on v
    Filter: f_leak(v.passwd)
    ->  Seq Scan on customer
-         Filter: (f_leak('passwd'::text) AND (name = ("current_user"())::text))
+         Filter: (f_leak('passwd'::text) AND (name = (CURRENT_USER)::text))
 (4 rows)
 
 --
@@ -1409,15 +1409,15 @@ NOTICE:  f_leak => 9801-2345-6789-0123
 (1 row)
 
 EXPLAIN (COSTS OFF) SELECT * FROM my_credit_card_normal WHERE f_leak(cnum);
-                       QUERY PLAN                        
----------------------------------------------------------
+                     QUERY PLAN                      
+-----------------------------------------------------
  Hash Join
    Hash Cond: (r.cid = l.cid)
    ->  Seq Scan on credit_card r
          Filter: f_leak(cnum)
    ->  Hash
          ->  Seq Scan on customer l
-               Filter: (name = ("current_user"())::text)
+               Filter: (name = (CURRENT_USER)::text)
 (7 rows)
 
 SELECT * FROM my_credit_card_secure WHERE f_leak(cnum);
@@ -1428,8 +1428,8 @@ NOTICE:  f_leak => 1111-2222-3333-4444
 (1 row)
 
 EXPLAIN (COSTS OFF) SELECT * FROM my_credit_card_secure WHERE f_leak(cnum);
-                          QUERY PLAN                           
----------------------------------------------------------------
+                        QUERY PLAN                         
+-----------------------------------------------------------
  Subquery Scan on my_credit_card_secure
    Filter: f_leak(my_credit_card_secure.cnum)
    ->  Hash Join
@@ -1437,7 +1437,7 @@ EXPLAIN (COSTS OFF) SELECT * FROM my_credit_card_secure WHERE f_leak(cnum);
          ->  Seq Scan on credit_card r
          ->  Hash
                ->  Seq Scan on customer l
-                     Filter: (name = ("current_user"())::text)
+                     Filter: (name = (CURRENT_USER)::text)
 (8 rows)
 
 --
@@ -1471,7 +1471,7 @@ EXPLAIN (COSTS OFF) SELECT * FROM my_credit_card_usage_normal
                      ->  Seq Scan on credit_card r_1
                      ->  Hash
                            ->  Seq Scan on customer l_1
-                                 Filter: (name = ("current_user"())::text)
+                                 Filter: (name = (CURRENT_USER)::text)
 (13 rows)
 
 SELECT * FROM my_credit_card_usage_secure
@@ -1502,7 +1502,7 @@ EXPLAIN (COSTS OFF) SELECT * FROM my_credit_card_usage_secure
                      ->  Seq Scan on credit_card r_1
                      ->  Hash
                            ->  Seq Scan on customer l
-                                 Filter: (name = ("current_user"())::text)
+                                 Filter: (name = (CURRENT_USER)::text)
 (13 rows)
 
 --