Implement chained expression order of operations (apache#1402)

Implements functionality for order of operations (parentheses) in
chained operations.

Added new nodes and functions to accomodate this feature.

Added relevant regression tests for order of operations in chained
expressions.

Modified a previous regression test case that had its location
reporting changed by this implementation.

regress/expected/cypher_call.out

@@ -84,8 +84,8 @@ HINT:  No function matches the given name and argument types. You might need to
 /* CALL YIELD WHERE, should fail */
 SELECT * FROM cypher('cypher_call', $$CALL sqrt(64) YIELD sqrt WHERE sqrt > 1$$) as (sqrt agtype);
 ERROR:  Cannot use standalone CALL with WHERE
-LINE 2: ...r('cypher_call', $$CALL sqrt(64) YIELD sqrt WHERE sqrt > 1$$...
-                                                             ^
+LINE 2: SELECT * FROM cypher('cypher_call', $$CALL sqrt(64) YIELD sq...
+                                             ^
 HINT:  Instead use `CALL ... WITH * WHERE ... RETURN *`
 /*
  * subquery

regress/expected/expr.out

@@ -741,6 +741,135 @@ SELECT * FROM cypher('chained', $$ MATCH (u:people) WHERE NOT 35 < u.age + 1 <=
  {"id": 844424930131973, "label": "people", "properties": {"age": 15, "name": "David"}}::vertex
 (3 rows)
 
+-- order of operations
+-- expressions
+SELECT * FROM cypher('chained', $$ RETURN 1 = 1 = 1 $$) AS (result agtype);
+ result 
+--------
+ true
+(1 row)
+
+SELECT * FROM cypher('chained', $$ RETURN 1 = 2 = 1 $$) AS (result agtype);
+ result 
+--------
+ false
+(1 row)
+
+SELECT * FROM cypher('chained', $$ RETURN (1 = 1) = 1 $$) AS (result agtype);
+ result 
+--------
+ false
+(1 row)
+
+SELECT * FROM cypher('chained', $$ RETURN 1 = (1 = 1) $$) AS (result agtype);
+ result 
+--------
+ false
+(1 row)
+
+SELECT * FROM cypher('chained', $$ RETURN 1 = 1 = true $$) AS (result agtype);
+ result 
+--------
+ false
+(1 row)
+
+SELECT * FROM cypher('chained', $$ RETURN (1 = 1) = true $$) AS (result agtype);
+ result 
+--------
+ true
+(1 row)
+
+SELECT * FROM cypher('chained', $$ RETURN true = ((1 = 1) = true) $$) AS (result agtype);
+ result 
+--------
+ true
+(1 row)
+
+SELECT * FROM cypher('chained', $$ RETURN ((1 = 1) = 1) = 1 $$) AS (result agtype);
+ result 
+--------
+ false
+(1 row)
+
+SELECT * FROM cypher('chained', $$ RETURN (1 = (1 = 1)) = 1 $$) AS (result agtype);
+ result 
+--------
+ false
+(1 row)
+
+SELECT * FROM cypher('chained', $$ RETURN ((1 = (1 = 1)) = 1) = 1 $$) AS (result agtype);
+ result 
+--------
+ false
+(1 row)
+
+-- in clause
+SELECT * FROM cypher('chained', $$ MATCH (u:people) WHERE 35 = u.age = 35  RETURN u $$) AS (result agtype);
+                                              result                                               
+---------------------------------------------------------------------------------------------------
+ {"id": 844424930131971, "label": "people", "properties": {"age": 35, "name": "Samantha"}}::vertex
+(1 row)
+
+SELECT * FROM cypher('chained', $$ MATCH (u:people) WHERE (35 = u.age) = 35  RETURN u $$) AS (result agtype);
+ result 
+--------
+(0 rows)
+
+SELECT * FROM cypher('chained', $$ MATCH (u:people) WHERE (35 = 35) = u.age  RETURN u $$) AS (result agtype);
+ result 
+--------
+(0 rows)
+
+SELECT * FROM cypher('chained', $$ MATCH (u:people) WHERE u.age = u.age = u.age  RETURN u $$) AS (result agtype);
+                                              result                                               
+---------------------------------------------------------------------------------------------------
+ {"id": 844424930131969, "label": "people", "properties": {"age": 50, "name": "Jason"}}::vertex
+ {"id": 844424930131970, "label": "people", "properties": {"age": 25, "name": "Amy"}}::vertex
+ {"id": 844424930131971, "label": "people", "properties": {"age": 35, "name": "Samantha"}}::vertex
+ {"id": 844424930131972, "label": "people", "properties": {"age": 40, "name": "Mark"}}::vertex
+ {"id": 844424930131973, "label": "people", "properties": {"age": 15, "name": "David"}}::vertex
+(5 rows)
+
+SELECT * FROM cypher('chained', $$ MATCH (u:people) WHERE (u.age = u.age) = u.age  RETURN u $$) AS (result agtype);
+ result 
+--------
+(0 rows)
+
+SELECT * FROM cypher('chained', $$ MATCH (u:people) WHERE u.age = (u.age = u.age)  RETURN u $$) AS (result agtype);
+ result 
+--------
+(0 rows)
+
+SELECT * FROM cypher('chained', $$ MATCH (u:people) WHERE (u.age = u.age) = (u.age = u.age)  RETURN u $$) AS (result agtype);
+                                              result                                               
+---------------------------------------------------------------------------------------------------
+ {"id": 844424930131969, "label": "people", "properties": {"age": 50, "name": "Jason"}}::vertex
+ {"id": 844424930131970, "label": "people", "properties": {"age": 25, "name": "Amy"}}::vertex
+ {"id": 844424930131971, "label": "people", "properties": {"age": 35, "name": "Samantha"}}::vertex
+ {"id": 844424930131972, "label": "people", "properties": {"age": 40, "name": "Mark"}}::vertex
+ {"id": 844424930131973, "label": "people", "properties": {"age": 15, "name": "David"}}::vertex
+(5 rows)
+
+SELECT * FROM cypher('chained', $$ MATCH (u:people) WHERE u.age = (u.age = (u.age = u.age))  RETURN u $$) AS (result agtype);
+ result 
+--------
+(0 rows)
+
+SELECT * FROM cypher('chained', $$ MATCH (u:people) WHERE u.age = 35 = ((u.age = u.age) = u.age) RETURN u $$) AS (result agtype);
+ result 
+--------
+(0 rows)
+
+SELECT * FROM cypher('chained', $$ MATCH (u:people) WHERE ((u.age = u.age) = (u.age = u.age)) = (u.age = u.age)  RETURN u $$) AS (result agtype);
+                                              result                                               
+---------------------------------------------------------------------------------------------------
+ {"id": 844424930131969, "label": "people", "properties": {"age": 50, "name": "Jason"}}::vertex
+ {"id": 844424930131970, "label": "people", "properties": {"age": 25, "name": "Amy"}}::vertex
+ {"id": 844424930131971, "label": "people", "properties": {"age": 35, "name": "Samantha"}}::vertex
+ {"id": 844424930131972, "label": "people", "properties": {"age": 40, "name": "Mark"}}::vertex
+ {"id": 844424930131973, "label": "people", "properties": {"age": 15, "name": "David"}}::vertex
+(5 rows)
+
 --
 -- Test transform logic for IS NULL & IS NOT NULL
 --

regress/sql/expr.sql

@@ -310,6 +310,31 @@ SELECT * FROM cypher('chained', $$ MATCH (u:people) WHERE 35 < u.age + 1 <= 50 R
 -- should return 3
 SELECT * FROM cypher('chained', $$ MATCH (u:people) WHERE NOT 35 < u.age + 1 <= 50 RETURN u $$) AS (result agtype);
 
+-- order of operations
+-- expressions
+SELECT * FROM cypher('chained', $$ RETURN 1 = 1 = 1 $$) AS (result agtype);
+SELECT * FROM cypher('chained', $$ RETURN 1 = 2 = 1 $$) AS (result agtype);
+SELECT * FROM cypher('chained', $$ RETURN (1 = 1) = 1 $$) AS (result agtype);
+SELECT * FROM cypher('chained', $$ RETURN 1 = (1 = 1) $$) AS (result agtype);
+SELECT * FROM cypher('chained', $$ RETURN 1 = 1 = true $$) AS (result agtype);
+SELECT * FROM cypher('chained', $$ RETURN (1 = 1) = true $$) AS (result agtype);
+SELECT * FROM cypher('chained', $$ RETURN true = ((1 = 1) = true) $$) AS (result agtype);
+SELECT * FROM cypher('chained', $$ RETURN ((1 = 1) = 1) = 1 $$) AS (result agtype);
+SELECT * FROM cypher('chained', $$ RETURN (1 = (1 = 1)) = 1 $$) AS (result agtype);
+SELECT * FROM cypher('chained', $$ RETURN ((1 = (1 = 1)) = 1) = 1 $$) AS (result agtype);
+
+-- in clause
+SELECT * FROM cypher('chained', $$ MATCH (u:people) WHERE 35 = u.age = 35  RETURN u $$) AS (result agtype);
+SELECT * FROM cypher('chained', $$ MATCH (u:people) WHERE (35 = u.age) = 35  RETURN u $$) AS (result agtype);
+SELECT * FROM cypher('chained', $$ MATCH (u:people) WHERE (35 = 35) = u.age  RETURN u $$) AS (result agtype);
+SELECT * FROM cypher('chained', $$ MATCH (u:people) WHERE u.age = u.age = u.age  RETURN u $$) AS (result agtype);
+SELECT * FROM cypher('chained', $$ MATCH (u:people) WHERE (u.age = u.age) = u.age  RETURN u $$) AS (result agtype);
+SELECT * FROM cypher('chained', $$ MATCH (u:people) WHERE u.age = (u.age = u.age)  RETURN u $$) AS (result agtype);
+SELECT * FROM cypher('chained', $$ MATCH (u:people) WHERE (u.age = u.age) = (u.age = u.age)  RETURN u $$) AS (result agtype);
+SELECT * FROM cypher('chained', $$ MATCH (u:people) WHERE u.age = (u.age = (u.age = u.age))  RETURN u $$) AS (result agtype);
+SELECT * FROM cypher('chained', $$ MATCH (u:people) WHERE u.age = 35 = ((u.age = u.age) = u.age) RETURN u $$) AS (result agtype);
+SELECT * FROM cypher('chained', $$ MATCH (u:people) WHERE ((u.age = u.age) = (u.age = u.age)) = (u.age = u.age)  RETURN u $$) AS (result agtype);
+
 --
 -- Test transform logic for IS NULL & IS NOT NULL
 --

src/backend/nodes/ag_nodes.c

@@ -48,6 +48,8 @@ const char *node_names[] = {
     "cypher_param",
     "cypher_map",
     "cypher_list",
+    "cypher_comparison_aexpr",
+    "cypher_comparison_boolexpr",
     "cypher_string_match",
     "cypher_typecast",
     "cypher_integer_const",
@@ -111,6 +113,8 @@ const ExtensibleNodeMethods node_methods[] = {
     DEFINE_NODE_METHODS(cypher_param),
     DEFINE_NODE_METHODS(cypher_map),
     DEFINE_NODE_METHODS(cypher_list),
+    DEFINE_NODE_METHODS(cypher_comparison_aexpr),
+    DEFINE_NODE_METHODS(cypher_comparison_boolexpr),
     DEFINE_NODE_METHODS(cypher_string_match),
     DEFINE_NODE_METHODS(cypher_typecast),
     DEFINE_NODE_METHODS(cypher_integer_const),

src/backend/nodes/cypher_outfuncs.c

@@ -259,6 +259,28 @@ void out_cypher_list(StringInfo str, const ExtensibleNode *node)
     WRITE_LOCATION_FIELD(location);
 }
 
+// serialization function for the cypher_comparison_aexpr ExtensibleNode.
+void out_cypher_comparison_aexpr(StringInfo str, const ExtensibleNode *node)
+{
+    DEFINE_AG_NODE(cypher_comparison_aexpr);
+
+    WRITE_ENUM_FIELD(kind, A_Expr_Kind);
+    WRITE_NODE_FIELD(name);
+    WRITE_NODE_FIELD(lexpr);
+    WRITE_NODE_FIELD(rexpr);
+    WRITE_LOCATION_FIELD(location);
+}
+
+// serialization function for the cypher_comparison_boolexpr ExtensibleNode.
+void out_cypher_comparison_boolexpr(StringInfo str, const ExtensibleNode *node)
+{
+    DEFINE_AG_NODE(cypher_comparison_boolexpr);
+
+    WRITE_ENUM_FIELD(boolop, BoolExprType);
+    WRITE_NODE_FIELD(args);
+    WRITE_LOCATION_FIELD(location);
+}
+
 // serialization function for the cypher_string_match ExtensibleNode.
 void out_cypher_string_match(StringInfo str, const ExtensibleNode *node)
 {

src/backend/parser/cypher_expr.c

@@ -73,7 +73,11 @@ static Node *transform_ColumnRef(cypher_parsestate *cpstate, ColumnRef *cref);
 static Node *transform_A_Indirection(cypher_parsestate *cpstate,
                                      A_Indirection *a_ind);
 static Node *transform_AEXPR_OP(cypher_parsestate *cpstate, A_Expr *a);
+static Node *transform_cypher_comparison_aexpr_OP(cypher_parsestate *cpstate,
+                                                  cypher_comparison_aexpr *a);
 static Node *transform_BoolExpr(cypher_parsestate *cpstate, BoolExpr *expr);
+static Node *transform_cypher_comparison_boolexpr(cypher_parsestate *cpstate,
+                                                  cypher_comparison_boolexpr *b);
 static Node *transform_cypher_bool_const(cypher_parsestate *cpstate,
                                          cypher_bool_const *bc);
 static Node *transform_cypher_integer_const(cypher_parsestate *cpstate,
@@ -193,6 +197,12 @@ static Node *transform_cypher_expr_recurse(cypher_parsestate *cpstate,
         if (is_ag_node(expr, cypher_typecast))
             return transform_cypher_typecast(cpstate,
                                              (cypher_typecast *)expr);
+        if (is_ag_node(expr, cypher_comparison_aexpr))
+            return transform_cypher_comparison_aexpr_OP(cpstate,
+                                             (cypher_comparison_aexpr *)expr);
+        if (is_ag_node(expr, cypher_comparison_boolexpr))
+            return transform_cypher_comparison_boolexpr(cpstate,
+                                             (cypher_comparison_boolexpr *)expr);
         ereport(ERROR,
                 (errmsg_internal("unrecognized ExtensibleNode: %s",
                                  ((ExtensibleNode *)expr)->extnodename)));
@@ -477,6 +487,25 @@ static Node *transform_AEXPR_OP(cypher_parsestate *cpstate, A_Expr *a)
                            a->location);
 }
 
+/*
+ * function for transforming cypher comparision A_Expr. Since this node is a
+ * wrapper to let us know when a comparison occurs in a chained comparison,
+ * we convert it to a regular A_expr and transform it.
+ */
+static Node *transform_cypher_comparison_aexpr_OP(cypher_parsestate *cpstate,
+                                                  cypher_comparison_aexpr *a)
+{
+    A_Expr *n = makeNode(A_Expr);
+    n->kind = a->kind;
+    n->name = a->name;
+    n->lexpr = a->lexpr;
+    n->rexpr = a->rexpr;
+    n->location = a->location;
+
+    return (Node *)transform_AEXPR_OP(cpstate, n);
+}
+
+
 static Node *transform_AEXPR_IN(cypher_parsestate *cpstate, A_Expr *a)
 {
     Oid func_in_oid;
@@ -535,6 +564,24 @@ static Node *transform_BoolExpr(cypher_parsestate *cpstate, BoolExpr *expr)
     return (Node *)makeBoolExpr(expr->boolop, args, expr->location);
 }
 
+/*
+ * function for transforming cypher_comparison_boolexpr. Since this node is a
+ * wrapper to let us know when a comparison occurs in a chained comparison,
+ * we convert it to a PG BoolExpr and transform it.
+ */
+static Node *transform_cypher_comparison_boolexpr(cypher_parsestate *cpstate,
+                                                  cypher_comparison_boolexpr *b)
+{
+    BoolExpr *n = makeNode(BoolExpr);
+
+    n->boolop = b->boolop;
+    n->args = b->args;
+    n->location = b->location;
+
+    return transform_BoolExpr(cpstate, n);
+}
+
+
 static Node *transform_cypher_bool_const(cypher_parsestate *cpstate,
                                          cypher_bool_const *bc)
 {