simplifying

lib/logical_plan.ml

@@ -1,31 +1,17 @@
 type logical_plan =
+  | Project of logical_plan * string
   | Scan of string (* Table name *)
-  | Filter of logical_plan * condition
+  | Filter of logical_plan 
   | Join of logical_plan * Ast.join_type * logical_plan 
-and condition = 
-  | Condition of string
+  | Group of logical_plan * string list
 
-let rec generate_from_clause tables =
-  match tables with
-  | [Ast.Table(name)] -> Scan(name)
-  | [Ast.Join(left, j_type, right, _)] -> 
-      Join(
-        generate_from_clause [left],
-        j_type,
-        generate_from_clause [right]
-      )
-  | _ -> failwith "Unsupported table structure"
-
-
-let generate_logical_plan ast =
+let ast_to_logical ast =
   match ast with 
-  | Ast.Query(Select(_, Some(tables), _)) -> 
-      let base_plan = generate_from_clause tables in
-      base_plan
-  | Ast.Query(Select(_, None, _)) -> failwith "not supported"
+  | Ast.Select(_, _) -> Project(Scan("table"), "ok")
+  | _ -> failwith "Query not supported yet"
 
-(*let evaluate_plan plan =
+let rec pp_logical_plan plan =
   match plan with 
-  | Scan(table) -> 
-  | _ -> failwith "Unsupported plan"
-*)
+  | Project(plan2, name) -> pp_logical_plan plan2 ^ name
+  | _ -> "Not supported"
+