Upgrade base

9 files changed, 405 insertions, 49 deletions

diff --git a/source/mod_student/plugin.ml b/source/mod_student/plugin.ml
index 26d15d0..41487d3 100644
--- a/source/mod_student/plugin.ml
+++ b/source/mod_student/plugin.ml
@@ -27,9 +27,20 @@ module Plugin : PLUGIN = struct
 
   let make_spill_costs_analysis = None
 
+  let lexer_and_parser = None
+  (*
+   * Przenieś pliki parser.mly oraz lexer.mll z poprzedniego rozwiązania 
+   * i odkomentuj poniższą linijkę.
+   *
+   * Przenoszenie rozwiązania nie jest wymagane. Pamiętaj, że możesz napotkać
+   * trudności gdy rozwiązanie z poprzedniej pracowni okaże się nie do końca
+   * kompatybilne z kształtem danych oczekiwanym przez resztę modułów
+   * kompilatora.
+   *
   let lexer_and_parser = Some (module LexerAndParser : LEXER_AND_PARSER)
+   *)
 
-  let make_typechecker = None
+  let make_typechecker = Some (module Typechecker.Make : MAKE_TYPECHECKER)
 
   let make_translator = None
 
@@ -58,4 +69,4 @@ module Plugin : PLUGIN = struct
   let make_reachability_analysis = None
 end
 
-module RegisterMyPlugin = RegisterPlugin(Plugin)
\ No newline at end of file
+module RegisterMyPlugin = RegisterPlugin(Plugin)
diff --git a/source/mod_student/typechecker.ml b/source/mod_student/typechecker.ml
new file mode 100644
index 0000000..800fecf
--- /dev/null
+++ b/source/mod_student/typechecker.ml
@@ -0,0 +1,231 @@
+open Xi_lib
+open Ast
+(* W Xi_lib.Types są definicje typów i środowiska typowego *)
+open Types
+
+module Make() = struct
+
+  (* Logger: używa się go jak Format.printf *)
+  let logf fmt = Logger.make_logf __MODULE__ fmt
+
+  module Check () = struct
+
+    (* Zgłaszaczka błędów *)
+    module ErrorReporter = Typechecker_errors.MakeOneShotErrorReporter ()
+
+    (* Hashtablica którą zwracamy jak wszystko jest OK.
+     * Mapuje znacznik węzła na przypisany typ. Dzięki tej tablicy
+     * późniejsze etapy kompilatora będą miały dostęp do policzonych
+     * typów wyrażeń 
+     * 
+     * Jeżeli typowanie się powiedzie to zawartość tablicy wydrukuje się
+     * do pliku xilog/004.typechecking.types
+     *)
+    let node2type_map = Hashtbl.create 513
+
+    (* --------------------------------------------------- *)
+    (* Funkcja nakładka na inferencję, jej zadanie to uzupełniać hashtablicę node2type_map *)
+    let rec infer_expression env e =
+      let tp = _infer_expression env e in
+      Hashtbl.replace node2type_map (tag_of_expression e) tp;
+      logf "%s: inferred type %s"
+        (string_of_location
+        (location_of_expression e))
+        (string_of_normal_type tp);
+      tp
+
+    (* --------------------------------------------------- *)
+    (* Oddolna strategia *)
+    and _infer_expression env = function
+      | EXPR_Id {id; loc; _} ->
+        failwith "Not yet implemented"
+
+      | EXPR_Int _ ->
+        TP_Int
+
+      | EXPR_Char _ ->
+        failwith "Not yet implemented"
+
+      | EXPR_Bool _ ->
+        failwith "Not yet implemented"
+
+      | EXPR_Index {expr;index;loc; _} ->
+        failwith "Not yet implemented"
+
+      | EXPR_Call call ->
+        check_function_call env call
+
+      | EXPR_Length {arg;loc;_} ->
+        failwith "Not yet implemented"
+
+      | EXPR_Relation {lhs; rhs; op=RELOP_Ge; _} 
+      | EXPR_Relation {lhs; rhs; op=RELOP_Gt; _} 
+      | EXPR_Relation {lhs; rhs; op=RELOP_Lt; _} 
+      | EXPR_Relation {lhs; rhs; op=RELOP_Le; _}  ->
+        failwith "Not yet implemented"
+
+      | EXPR_Relation {lhs; rhs; op=RELOP_Eq; _} 
+      | EXPR_Relation {lhs; rhs; op=RELOP_Ne; _} ->
+        failwith "Not yet implemented"
+
+        (* Reguła dla dodawania, jak w treści zadania *)
+      | EXPR_Binop {loc; lhs; rhs; op=BINOP_Add; _} ->
+        begin match infer_expression env lhs with
+        | (TP_Array _) as tp
+        | (TP_Int as tp) ->
+          check_expression env tp rhs;
+          tp
+        | _ ->
+          let descr = "operator + expects integer or array" in
+         ErrorReporter.report_other_error ~loc ~descr
+        end
+
+      | EXPR_Binop {lhs; rhs; op=BINOP_And;_} 
+      | EXPR_Binop {lhs; rhs; op=BINOP_Or; _} ->
+        failwith "not yet implemented"
+
+      | EXPR_Binop {lhs; rhs; op=BINOP_Sub;_} 
+      | EXPR_Binop {lhs; rhs; op=BINOP_Rem;_} 
+      | EXPR_Binop {lhs; rhs; op=BINOP_Mult;_} 
+      | EXPR_Binop {lhs; rhs; op=BINOP_Div; _} ->
+        failwith "not yet implemented"
+
+      | EXPR_Unop {op=UNOP_Neg; sub; _} ->
+        failwith "not yet implemented"
+
+      | EXPR_Unop {op=UNOP_Not; sub; _} ->
+        failwith "not yet implemented"
+
+      | EXPR_String _ ->
+        failwith "not yet implemented"
+
+      | EXPR_Struct {elements=[]; loc; _} ->
+        ErrorReporter.report_cannot_infer ~loc
+
+      | EXPR_Struct {elements=x::xs; _} ->
+        failwith "not yet implemented"
+
+    and check_function_call env call = 
+      failwith "not yet implemented"
+
+    (* --------------------------------------------------- *)
+    (* Odgórna strategia: zapish w node2type_map oczekiwanie a następnie
+     * sprawdź czy nie zachodzi specjalny przypadek. *)
+    and check_expression env expected e =
+      logf "%s: checking expression against %s"
+        (string_of_location (location_of_expression e))
+        (string_of_normal_type expected);
+      Hashtbl.replace node2type_map (tag_of_expression e) expected;
+
+      (* Sprawdzamy specjalne przypadki *)
+      match e, expected with
+          (* Mamy sprawdzić `{elements...}` kontra `tp[]`, czyli sprawdzamy 
+          * elementy kontra typ elementu tablicy `tp` *)
+      | EXPR_Struct {elements; _}, TP_Array tp ->
+        List.iter (check_expression env tp) elements
+
+      (* ========== !! Zaimplementuj pozostale przypadki !! =========  *)
+
+      (* Fallback do strategii oddolnej *)
+      | _ ->
+        let actual = infer_expression env e in
+        if actual <> expected then
+          ErrorReporter.report_type_mismatch
+            ~loc:(location_of_expression e)
+            ~actual
+            ~expected
+
+    (* --------------------------------------------------- *)
+    (* Pomocnicza funkcja do sprawdzania wywołania procedury *)
+
+    let check_procedure_call env call : unit = 
+      failwith "not yet implemented"
+
+    (* --------------------------------------------------- *)
+    (* Rekonstrukcja typu dla lvalue *)
+
+    let infer_lvalue env = function
+      | LVALUE_Id {id;loc;_} -> 
+        failwith "not yet implemented"
+
+      | LVALUE_Index {index; sub; loc} ->
+        failwith "not yet implemented"
+
+
+    (* --------------------------------------------------- *)
+    (* Sprawdzanie statementów *)
+
+    let rec check_statement env = function
+      (* Proste, wyinferuj typ `lhs` i sprawdź `rhs` kontra wynik *)
+      | STMT_Assign {lhs; rhs; _} ->
+        let lhs_tp = infer_lvalue env lhs in
+        check_expression env lhs_tp rhs;
+        env, RT_Unit
+
+      | STMT_MultiVarDecl {vars; init; _} ->
+        failwith "not yet implemented"
+
+      | STMT_Block body ->
+        check_statement_block env body
+
+      | STMT_Call call ->
+        check_procedure_call env call;
+        env, RT_Unit
+
+      | STMT_If {cond;then_branch;else_branch; _} ->
+        failwith "not yet implemented"
+
+      | STMT_Return {values;loc} ->
+        failwith "not yet implemented"
+
+      | STMT_VarDecl {var; init} ->
+        failwith "not yet implemented"
+
+      | STMT_While {cond; body; _} ->
+        failwith "not yet implemented"
+
+    and check_statement_block env (STMTBlock {body; _}) =
+        failwith "not yet implemented"
+
+    (* --------------------------------------------------- *)
+    (* Top-level funkcje *)
+
+    let check_global_declaration env = function
+      | GDECL_Function {formal_parameters; return_types; body; loc; id; _} ->
+        (* Sprawdź wszystko *)
+        failwith "not yet implemented"
+
+    let scan_global_declaration env = function
+      | GDECL_Function {id; formal_parameters; return_types; loc; _} ->
+        (* Dodaj idenetyfkator funkcji i jej typ do środowiska *)
+        failwith "not yet implemented"
+
+    let scan_module env (ModuleDefinition {global_declarations; _}) =
+      List.fold_left scan_global_declaration env global_declarations
+
+    let check_module env (ModuleDefinition {global_declarations; _}) =
+      List.iter (check_global_declaration env) global_declarations
+
+    (* --------------------------------------------------- *)
+    (* Przetwórz moduł *)
+    let process_module env mdef =
+      (* Wpierw przeskanuj globalne definicje aby uzupełnić środowisko *)
+      let env = scan_module env mdef in
+      (* Zweryfikuj wszystko *)
+      check_module env mdef
+
+    let computation mdef = 
+      (* Zaczynamy z pustym środowiskiem *)
+      let env = TypingEnvironment.empty in
+      process_module env mdef;
+      node2type_map
+  end
+
+  (* --------------------------------------------------- *)
+  (* Procedura wejściowa *)
+  let check_module mdef =
+    (* Stwórz instancję typecheckera i ją odpal *)
+    let module M = Check() in
+    M.ErrorReporter.wrap M.computation mdef 
+
+end
diff --git a/source/xi/.merlin b/source/xi/.merlin
deleted file mode 100644
index 615c7ba..0000000
--- a/source/xi/.merlin
+++ /dev/null
@@ -1,15 +0,0 @@
-B /usr/home/pawel/.opam/4.07.0/lib/bytes
-B /usr/home/pawel/.opam/4.07.0/lib/cmdliner
-B /usr/home/pawel/.opam/4.07.0/lib/ocaml
-B /usr/home/pawel/.opam/4.07.0/lib/ocamlgraph
-B /usr/home/pawel/.opam/4.07.0/lib/result
-B ../../_build/default/source/xi/.xi.eobjs
-B ../../_build/default/source/xi_lib/.xi_lib.objs
-S /usr/home/pawel/.opam/4.07.0/lib/bytes
-S /usr/home/pawel/.opam/4.07.0/lib/cmdliner
-S /usr/home/pawel/.opam/4.07.0/lib/ocaml
-S /usr/home/pawel/.opam/4.07.0/lib/ocamlgraph
-S /usr/home/pawel/.opam/4.07.0/lib/result
-S .
-S ../xi_lib
-FLG -w @a-4-29-40-41-42-44-45-48-58-59-60-40 -strict-sequence -strict-formats -short-paths -keep-locs -g -w -39-33-26-27
diff --git a/source/xi/pipeline.ml b/source/xi/pipeline.ml
index 34a06f9..ae9a4c9 100644
--- a/source/xi/pipeline.ml
+++ b/source/xi/pipeline.ml
@@ -31,10 +31,21 @@ module Make(Steps:COMPILER_STEPS)(Params:PARAMS) = struct
     Logger.dump_string "regmapping" @@ describe_register_mapping mapping
 
   let dump_schedule proc_ir schedule = 
-    let title = Format.sprintf "%s.schedule" (Ir_utils.string_of_procid @@ Ir.procid_of_procedure proc_ir) in
+    let title = Format.sprintf "%s.schedule" (Ir_utils.string_of_procid proc_ir) in
     let output = Ir_utils.string_of_labellist schedule in
     Logger.dump_string title output
 
+  let dump_node2type node2type =
+    let title = "types" in 
+    let f k v xs =
+      let line = Format.sprintf "%s -> %s"
+        (Ast.string_of_node_tag k)
+        (Types.string_of_normal_type v) in
+      line :: xs
+    in
+    let lines = Hashtbl.fold f node2type [] in
+    Logger.dump_string title @@ String.concat "\n" @@ List.sort compare lines
+
   module IrPhases = struct
 
     let regalloc proc =
@@ -111,6 +122,7 @@ module Make(Steps:COMPILER_STEPS)(Params:PARAMS) = struct
       List.iter prerr_endline xs;
       Error "typechecker"
     | Ok (node2type) ->
+      dump_node2type node2type;
       if Invariants.AllExpressionsAreTypecheck.verify_module_definition node2type ast then
         check_stop_point "typechecker" translate (ast, node2type)
       else
diff --git a/source/xi/xi.ml b/source/xi/xi.ml
index 86a23f1..d59dbf6 100644
--- a/source/xi/xi.ml
+++ b/source/xi/xi.ml
@@ -72,7 +72,7 @@ module CommandLine = struct
 
   let cmd =
     let doc = "Compile Xi Program" in
-    let version = "pracownia1.1-0-gc10b4f2" in
+    let version = "pracownia2.3-0-g63fd12e" in
     Term.(const compile $ xi_log $ extra_debug $ mod_uwr $ plugin $ reg_descr $ stop_after $ output $ source_file),
     Term.info "xi" ~doc ~version
 
diff --git a/source/xi_lib/.merlin b/source/xi_lib/.merlin
deleted file mode 100644
index eafe161..0000000
--- a/source/xi_lib/.merlin
+++ /dev/null
@@ -1,5 +0,0 @@
-B /usr/home/pawel/.opam/4.07.0/lib/ocamlgraph
-B ../../_build/default/source/xi_lib/.xi_lib.objs
-S /usr/home/pawel/.opam/4.07.0/lib/ocamlgraph
-S .
-FLG -open Xi_lib -w @a-4-29-40-41-42-44-45-48-58-59-60-40 -strict-sequence -strict-formats -short-paths -keep-locs
diff --git a/source/xi_lib/iface.ml b/source/xi_lib/iface.ml
index b67a787..04658e0 100644
--- a/source/xi_lib/iface.ml
+++ b/source/xi_lib/iface.ml
@@ -1,7 +1,7 @@
 
 type node2type = (Ast.node_tag, Types.normal_type) Hashtbl.t
 
-type schedule = (Ir.procedure, Ir.label list) Hashtbl.t
+type schedule = (Ir.procid, Ir.label list) Hashtbl.t
 
 type register_mapping = (Ir.reg, Ir.reg) Hashtbl.t
 
diff --git a/source/xi_lib/typechecker_errors.ml b/source/xi_lib/typechecker_errors.ml
index f3ee529..4799a6b 100644
--- a/source/xi_lib/typechecker_errors.ml
+++ b/source/xi_lib/typechecker_errors.ml
@@ -2,12 +2,15 @@ open Ast
 open Types
 
 type type_checking_error =
+
+    (* Ogólny błąd, że oczekiwany typ się nie zgadza z rzeczywistym *)
   | TCERR_TypeMismatch of
     { loc: location
     ; expected: normal_type
     ; actual: normal_type
     }
 
+    (* Błąd typu przy multireturn *)
   | TCERR_BindingTypeMismatch of
     { loc: location
     ; expected: normal_type
@@ -15,48 +18,57 @@ type type_checking_error =
     ; id: identifier
     }
 
+    (* Wywołaliśmy procedurę/funkcję ze złą liczbą argumentów *)
   | TCERR_BadNumberOfActualArguments of
     { loc: location
     ; expected: int
     ; actual: int
     }
 
+    (* Return dostał złą liczbę parametrów *)
   | TCERR_BadNumberOfReturnValues of
     { loc: location
     ; expected: int
     ; actual: int
     }
 
+    (* Nieznany identyfikator *)
   | TCERR_UnknownIdentifier of
     { loc: location
     ; id: identifier
     }
 
+    (* Identyfikator nie jest zmienną (a np jest funkcją) *)
   | TCERR_IdentifierIsNotVariable of
     { loc: location
     ; id: identifier
     }
 
+    (* Generyczny błąd gdyby inne nie pasowały *)
   | TCERR_OtherError of
     { loc: location
     ; descr: string
     }
 
+    (* Wywołujemy identyfikator, który nie jest funkcją/procedurą *)
   | TCERR_IdentifierIsNotCallable of
     { loc: location
     ; id: identifier
     }
 
+    (* Brakuje return gdzieś *)
   | TCERR_NotAllControlPathsReturnValue of
     { loc: location
     ; id: identifier
     }
 
+    (* Użyliśmy w wyrażeniu multireturnowej funkcji *)
   | TCERR_ExpectedFunctionReturningOneValue of
     { loc: location
     ; id: identifier
     }
 
+    (* Użyliśmy w multireturnie zywkłej funkcji *)
   | TCERR_ExpectedFunctionReturningManyValues of
     { loc: location
     ; expected: int
@@ -64,33 +76,33 @@ type type_checking_error =
     ; id: identifier
     }
 
+    (* Return w procedurze *)
   | TCERR_ProcedureCannotReturnValue of
     { loc: location
     }
 
+    (* Brakuje parametru w return *)
   | TCERR_FunctionMustReturnValue of
     { loc: location
     }
   
+    (* Typ miał być tablicą *)
   | TCERR_ExpectedArray of
     { loc: location
     ; actual: normal_type
     }
 
-  | TCERR_InvalidRedeclaration of
-    { loc: location
-    ; id: identifier
-    ; previous: env_type
-    }
-
+    (* Przykryliśmy nazwę *)
   | TCERR_ShadowsPreviousDefinition of
     { loc: location
     ; id: identifier
     }
 
+    (* W wyrażeniu typowym pojawiło się wyrażenie oznaczające rozmiar *)
   | TCERR_ArrayInitializationForbidden of
     { loc: location }
 
+    (* Generyczny błąd, że nie dało się zrekonstruować typu *)
   | TCERR_CannotInferType of
     { loc: location }
 
@@ -169,12 +181,6 @@ let string_of_type_checking_error = function
     Format.sprintf "%s: procedure cannot return value"
       (string_of_location loc)
 
-  | TCERR_InvalidRedeclaration {loc; id; previous} ->
-    Format.sprintf "%s: invalid redeclaration: %s: previous type: %s"
-      (string_of_location loc)
-      (string_of_identifier id)
-      (string_of_env_type previous)
-
   | TCERR_ShadowsPreviousDefinition {loc; id} ->
     Format.sprintf "%s: shadows previous definition: %s"
       (string_of_location loc)
@@ -188,19 +194,30 @@ let string_of_type_checking_error = function
     Format.sprintf "%s: cannot infer type"
       (string_of_location loc)
 
-  module MakeErrorReporter () = struct
+
+
+
+  module MakeCollectingErrorReporter () = struct
 
     let r = ref []
 
     let add e = r := e :: !r
 
+    let wrap f x =
+      let result = f x in
+      let errors = List.rev !r in
+      r := [];
+      match errors with
+      | [] -> Ok result
+      | xs -> Error xs
+
     let report_type_mismatch ~loc ~expected ~actual =
       add @@ TCERR_TypeMismatch {loc;expected;actual}
 
     let report_binding_type_mismatch ~loc ~expected ~actual ~id =
       add @@ TCERR_BindingTypeMismatch {loc;expected;actual; id}
 
-    let report_error ~loc ~descr =
+    let report_other_error ~loc ~descr =
       add @@ TCERR_OtherError {loc; descr}
 
     let report_identifier_is_not_variable ~loc ~id =
@@ -239,19 +256,77 @@ let string_of_type_checking_error = function
     let report_shadows_previous_definition ~loc ~id =
       add @@ TCERR_ShadowsPreviousDefinition {loc; id}
 
-    let report_invalid_redeclaration ~loc ~id ~previous =
-      add @@ TCERR_InvalidRedeclaration {loc; id; previous}
-
     let report_array_initialization_forbidden ~loc =
       add @@ TCERR_ArrayInitializationForbidden {loc}
 
     let report_cannot_infer ~loc =
       add @@ TCERR_CannotInferType {loc}
 
-    let flush () =
-      let result = List.rev !r in
-      r := [];
-      result
 
+  end
+
+  (* Kopia poniewaz chcemy aby typ wyniku funkcji `add` był dowolny bo sterowanie się kończy przez raise *)
+  module MakeOneShotErrorReporter() = struct 
+
+    exception TypeCheckingError of type_checking_error
+
+    let add e = raise (TypeCheckingError e)
 
-  end
\ No newline at end of file
+    let wrap f x =
+      try
+        Ok (f x)
+      with (TypeCheckingError e) ->
+        Error [e]
+
+    let report_type_mismatch ~loc ~expected ~actual =
+      add @@ TCERR_TypeMismatch {loc;expected;actual}
+
+    let report_binding_type_mismatch ~loc ~expected ~actual ~id =
+      add @@ TCERR_BindingTypeMismatch {loc;expected;actual; id}
+
+    let report_other_error ~loc ~descr =
+      add @@ TCERR_OtherError {loc; descr}
+
+    let report_identifier_is_not_variable ~loc ~id =
+      add @@ TCERR_IdentifierIsNotVariable {loc; id}
+
+    let report_unknown_identifier ~loc ~id =
+      add @@ TCERR_UnknownIdentifier {loc; id}
+
+    let report_identifier_is_not_callable ~loc ~id =
+      add @@ TCERR_IdentifierIsNotCallable {loc; id}
+
+    let report_bad_number_of_arguments ~loc ~expected ~actual =
+      add @@ TCERR_BadNumberOfActualArguments {loc; expected; actual}
+
+    let report_bad_number_of_return_values ~loc ~expected ~actual =
+      add @@ TCERR_BadNumberOfReturnValues {loc; expected; actual}
+
+    let report_expected_function_returning_one_value ~loc ~id =
+      add @@ TCERR_ExpectedFunctionReturningOneValue {loc;id}
+
+    let report_expected_function_returning_many_values ~loc ~id ~expected ~actual =
+      add @@ TCERR_ExpectedFunctionReturningManyValues {loc;id; expected;actual}
+
+    let report_function_must_return_something ~loc =
+      add @@ TCERR_FunctionMustReturnValue {loc}
+
+    let report_procedure_cannot_return_value ~loc =
+      add @@ TCERR_ProcedureCannotReturnValue {loc}
+
+    let report_expected_array ~loc ~actual =
+      add @@ TCERR_ExpectedArray {loc; actual}
+
+    let report_not_all_control_paths_return_value ~loc ~id =
+      add @@ TCERR_NotAllControlPathsReturnValue {loc; id}
+
+    let report_shadows_previous_definition ~loc ~id =
+      add @@ TCERR_ShadowsPreviousDefinition {loc; id}
+
+    let report_array_initialization_forbidden ~loc =
+      add @@ TCERR_ArrayInitializationForbidden {loc}
+
+    let report_cannot_infer ~loc =
+      add @@ TCERR_CannotInferType {loc}
+  
+  end 
diff --git a/source/xi_lib/types.ml b/source/xi_lib/types.ml
index 14809cc..398b2e9 100644
--- a/source/xi_lib/types.ml
+++ b/source/xi_lib/types.ml
@@ -1,4 +1,3 @@
-
 type normal_type
   = TP_Int
   | TP_Bool
@@ -9,6 +8,11 @@ let rec string_of_normal_type = function
   | TP_Bool -> "bool"
   | TP_Array el -> string_of_normal_type el ^ "[]"
 
+(* Rozszerzony typ
+ * Lista 0 elementów - unit
+ * Lista 1 element - normalny typ
+ * Lista n elementów - krotka
+ *)
 type extended_type = normal_type list
 
 let string_of_extended_type xs =
@@ -28,4 +32,47 @@ let string_of_env_type = function
     (string_of_extended_type xs)
   | ENVTP_Fn (xs, rs) -> Format.sprintf "fn(%s) -> (%s)"
     (string_of_extended_type xs)
-    (string_of_extended_type rs)
\ No newline at end of file
+    (string_of_extended_type rs)
+
+module TypingEnvironment = struct
+
+  (* W przeciwieństwie do specyfikacji nie trzymamy specjalnej zmiennej `ro`
+    * oznaczającej return type. Trzymamy to w oddzielnym polu dla
+    *  przejrzystości.
+    *)
+
+  type t = 
+    { mapping: env_type Ast.IdMap.t
+    ; return: extended_type option
+    }
+
+  (* Dodaj do środowiska.
+    * Zwraca nowe środowisko oraz informację czy dany klucz `x` już nie był
+    * w kontekście. Jak był to nic nie zwracamy, klient zapyta o starą wartość
+    * by zgłosić komunikat o błędzie. Ta informacja o dodawaniu jest używana
+    * aby wykrywać przykrywanie zmiennych.
+    *)
+  let add (x:Ast.identifier) (t:env_type) (env:t) =
+    if Ast.IdMap.mem x env.mapping then
+      env ,
+      false
+    else
+      {env with mapping=Ast.IdMap.add x t env.mapping},
+      true
+
+  (* Pobranie, zwraca option *)
+  let lookup x (t : t) = Ast.IdMap.find_opt x t.mapping
+
+  (* Gdy wiemy że klucz jest w bazie i nie chce nam się rozpatrywać czy było
+    * Some czy None *)
+  let lookup_unsafe x t = 
+    match lookup x t with
+    | None -> failwith "TypingEnvironment.lookup_unsafe failed"
+    | Some x -> x
+
+  let empty : t = { mapping=Ast.IdMap.empty; return=None}
+
+  let set_return t r = {t with return=Some r}
+
+  let get_return t = t.return
+end
\ No newline at end of file