Cross appy support

Author: alex-kulakov

Orm/Xtensive.Orm.Firebird/Sql.Drivers.Firebird/v4_0/ServerInfoProvider.cs

@@ -1,11 +1,20 @@
-using System;
-using System.Collections.Generic;
-using System.Text;
+// Copyright (C) 2021 Xtensive LLC.
+// This code is distributed under MIT license terms.
+// See the License.txt file in the project root for more information.
+
+using Xtensive.Sql.Info;
 
 namespace Xtensive.Sql.Drivers.Firebird.v4_0
 {
   internal class ServerInfoProvider : v2_5.ServerInfoProvider
   {
+    public override QueryInfo GetQueryInfo()
+    {
+      var info = base.GetQueryInfo();
+      info.Features |= QueryFeatures.CrossApply;
+      return info;
+    }
+
     public ServerInfoProvider(SqlDriver driver)
       : base(driver)
     {

Orm/Xtensive.Orm.Firebird/Sql.Drivers.Firebird/v4_0/Translator.cs

@@ -1,11 +1,40 @@
-using System;
-using System.Collections.Generic;
-using System.Text;
+// Copyright (C) 2021 Xtensive LLC.
+// This code is distributed under MIT license terms.
+// See the License.txt file in the project root for more information.
+
+using Xtensive.Sql.Compiler;
+using Xtensive.Sql.Dml;
 
 namespace Xtensive.Sql.Drivers.Firebird.v4_0
 {
   internal class Translator : v2_5.Translator
   {
+    public override string Translate(SqlCompilerContext context, SqlJoinExpression node, JoinSection section)
+    {
+      switch (section) {
+        case JoinSection.Specification: {
+          if (node.Expression == null) {
+            switch (node.JoinType) {
+              case SqlJoinType.CrossApply:
+                return "CROSS JOIN LATERAL";
+              case SqlJoinType.LeftOuterApply:
+                return "LEFT JOIN LATERAL";
+              default:
+                return base.Translate(context, node, section);
+            }
+          }
+          return Translate(node.JoinType) + " JOIN";
+        }
+        case JoinSection.Exit: {
+          if (node.JoinType == SqlJoinType.LeftOuterApply) {
+            return "ON TRUE";
+          }
+          return string.Empty;
+        }
+      }
+      return base.Translate(context, node, section);
+    }
+
     // Constructors
 
     /// <inheritdoc/>