Add schema to functions

Some functions may require schema before the name. E.g.: MonetDB json.isarray
function: json.isarray('[1, 2, 3]'). PostgreSQL also allows it: "Schemas also
contain other kinds of named objects, including data types, functions, and
operators." (https://www.postgresql.org/docs/current/ddl-schemas.html). Let's
support it.

Author: msiomkin

src/parser/bison_parser.y

@@ -1171,7 +1171,9 @@ comp_expr : operand '=' operand { $$ = Expr::makeOpBinary($1, kOpEquals, $3); }
 // `function_expr is used for window functions, aggregate expressions, and functions calls because we run into shift/
 // reduce conflicts when splitting them.
 function_expr : IDENTIFIER '(' ')' opt_window { $$ = Expr::makeFunctionRef($1, new std::vector<Expr*>(), false, $4); }
-| IDENTIFIER '(' opt_distinct expr_list ')' opt_window { $$ = Expr::makeFunctionRef($1, $4, $3, $6); };
+| IDENTIFIER '(' opt_distinct expr_list ')' opt_window { $$ = Expr::makeFunctionRef($1, $4, $3, $6); }
+| IDENTIFIER '.' IDENTIFIER '(' ')' opt_window { $$ = Expr::makeFunctionRef($3, $1, new std::vector<Expr*>(), false, $6); }
+| IDENTIFIER '.' IDENTIFIER '(' opt_distinct expr_list ')' opt_window { $$ = Expr::makeFunctionRef($3, $1, $6, $5, $8); };
 
 // Window function expressions, based on https://www.postgresql.org/docs/15/sql-expressions.html#SYNTAX-WINDOW-FUNCTIONS
 // We do not support named windows, collations and exclusions (for simplicity) and filters (not part of the SQL standard).

src/sql/Expr.cpp

@@ -49,6 +49,7 @@ Expr::Expr(ExprType type)
       select(nullptr),
       name(nullptr),
       table(nullptr),
+      schema(nullptr),
       alias(nullptr),
       fval(0),
       ival(0),
@@ -68,6 +69,7 @@ Expr::~Expr() {
 
   free(name);
   free(table);
+  free(schema);
   free(alias);
 
   if (exprList) {
@@ -219,6 +221,16 @@ Expr* Expr::makeFunctionRef(char* func_name, std::vector<Expr*>* exprList, bool
   return e;
 }
 
+Expr* Expr::makeFunctionRef(char* func_name, char* schema, std::vector<Expr*>* exprList, bool distinct, WindowDescription* window) {
+  Expr* e = new Expr(kExprFunctionRef);
+  e->name = func_name;
+  e->schema = schema;
+  e->exprList = exprList;
+  e->distinct = distinct;
+  e->windowDescription = window;
+  return e;
+}
+
 Expr* Expr::makeArray(std::vector<Expr*>* exprList) {
   Expr* e = new Expr(kExprArray);
   e->exprList = exprList;

src/sql/Expr.h

@@ -133,6 +133,7 @@ struct Expr {
   SelectStatement* select;
   char* name;
   char* table;
+  char* schema;
   char* alias;
   double fval;
   int64_t ival;
@@ -200,6 +201,8 @@ struct Expr {
 
   static Expr* makeFunctionRef(char* func_name, std::vector<Expr*>* exprList, bool distinct, WindowDescription* window);
 
+  static Expr* makeFunctionRef(char* func_name, char* schema, std::vector<Expr*>* exprList, bool distinct, WindowDescription* window);
+
   static Expr* makeArray(std::vector<Expr*>* exprList);
 
   static Expr* makeArrayIndex(Expr* expr, int64_t index);

test/select_tests.cpp

@@ -1255,4 +1255,26 @@ TEST(WindowFunctions) {
   }
 }
 
+TEST(FunctionSchema) {
+  TEST_PARSE_SQL_QUERY(
+      "SELECT sys.uuid();"
+      "SELECT json.isarray('[1, 2, 3]');"
+      result, 1);
+
+  auto stmt = (SelectStatement*)result.getStatement(0);
+  ASSERT_TRUE(stmt->selectList);
+  ASSERT_EQ(stmt->selectList->size(), 1);
+  ASSERT_STREQ(stmt->selectList->at(0)->schema, "sys");
+  ASSERT_STREQ(stmt->selectList->at(0)->name, "uuid");
+  ASSERT_EQ(stmt->selectList->at(0)->exprList->size, 0);
+
+  auto stmt = (SelectStatement*)result.getStatement(1);
+  ASSERT_TRUE(stmt->selectList);
+  ASSERT_EQ(stmt->selectList->size(), 1);
+  ASSERT_STREQ(stmt->selectList->at(0)->schema, "json");
+  ASSERT_STREQ(stmt->selectList->at(0)->name, "isarray");
+  ASSERT_EQ(stmt->selectList->at(0)->exprList->size, 1);
+  ASSERT_STREQ(stmt->selectList->at(0)->exprList->at(0)->name, "'[1, 2, 3]'");
+}
+
 }  // namespace hsql