draft for parquet parsing

lib/dune

@@ -6,3 +6,7 @@
  (modules logical_plan)
  (libraries ast)
  (name logical_plan))
+
+(library
+ (modules parquet)
+ (name parquet))

lib/logical_plan.ml

@@ -21,7 +21,8 @@ and generate_from_clause tables =
   | _ -> failwith "Unsupported table structure"
 
 
-let evaluate_plan plan =
+(*let evaluate_plan plan =
   match plan with
   | Scan(table) -> 
   | _ -> failwith "Unsupported plan"
+*)

lib/parquet.ml

@@ -0,0 +1,9 @@
+let parquet_check_prefix ic = 
+  let par = really_input_string ic 4 in
+  "PAR1" = par
+  
+let parquet_check_suffix ic =
+  let len = in_channel_length ic in
+  seek_in ic (len - 4);
+  let par = really_input_string ic 4 in
+  "PAR1" = par

test/dune

@@ -5,3 +5,10 @@
 (test
  (name logical_plan_test)
  (libraries ast logical_plan))
+
+
+(test
+ (name test_parquet)
+ (libraries parquet)
+ (deps
+   (file ./files/parquet/mock_data.parquet)))

test/test_parquet.ml

@@ -0,0 +1,7 @@
+open Parquet
+
+let () =
+  let path = "files/parquet/mock_data.parquet" in
+  let ic = open_in path in
+  assert(parquet_check_prefix ic = true);
+  assert(parquet_check_suffix ic = true)