Add back TypEr to the main OTP repository

It turned out that the dependencies between Dialyzer
and TypEr makes it impractical to have TypEr in a
separate repository.

Add it back to the OTP repository, but put the Erlang
module 'typer' in the dialyzer application.

3 files changed, 1117 insertions, 2 deletions

diff --git a/lib/dialyzer/src/Makefile b/lib/dialyzer/src/Makefile
index 256f20f549..28f74ed441 100644
--- a/lib/dialyzer/src/Makefile
+++ b/lib/dialyzer/src/Makefile
@@ -68,7 +68,8 @@ MODULES =  \
 	dialyzer_typesig \
 	dialyzer_coordinator \
 	dialyzer_worker \
-	dialyzer_utils
+	dialyzer_utils \
+	typer
 
 HRL_FILES= dialyzer.hrl dialyzer_gui_wx.hrl
 ERL_FILES= $(MODULES:%=%.erl)
@@ -117,6 +118,9 @@ $(EBIN)/dialyzer_plt.$(EMULATOR): dialyzer_plt.erl ../vsn.mk
 $(EBIN)/dialyzer_gui_wx.$(EMULATOR): dialyzer_gui_wx.erl ../vsn.mk
 	$(erlc_verbose)erlc -W  $(ERL_COMPILE_FLAGS) -DVSN="\"v$(VSN)\"" -o$(EBIN) dialyzer_gui_wx.erl
 
+$(EBIN)/typer.$(EMULATOR): typer.erl ../vsn.mk
+	$(erlc_verbose)erlc -W  $(ERL_COMPILE_FLAGS) -DVSN="\"v$(VSN)\"" -o$(EBIN) typer.erl
+
 $(APP_TARGET): $(APP_SRC) ../vsn.mk
 	$(vsn_verbose)sed -e 's;%VSN%;$(VSN);' $< > $@
 
diff --git a/lib/dialyzer/src/dialyzer.app.src b/lib/dialyzer/src/dialyzer.app.src
index f517c51ec1..5f803875b0 100644
--- a/lib/dialyzer/src/dialyzer.app.src
+++ b/lib/dialyzer/src/dialyzer.app.src
@@ -43,7 +43,8 @@
 	     dialyzer_typesig,
 	     dialyzer_utils,
              dialyzer_timing,
-             dialyzer_worker]},
+             dialyzer_worker,
+             typer]},
   {registered, []},
   {applications, [compiler, hipe, kernel, stdlib, wx]},
   {env, []},
diff --git a/lib/dialyzer/src/typer.erl b/lib/dialyzer/src/typer.erl
new file mode 100644
index 0000000000..18c4fe902d
--- /dev/null
+++ b/lib/dialyzer/src/typer.erl
@@ -0,0 +1,1110 @@
+%% -*- erlang-indent-level: 2 -*-
+%%
+%% Licensed under the Apache License, Version 2.0 (the "License");
+%% you may not use this file except in compliance with the License.
+%% You may obtain a copy of the License at
+%%
+%%     http://www.apache.org/licenses/LICENSE-2.0
+%%
+%% Unless required by applicable law or agreed to in writing, software
+%% distributed under the License is distributed on an "AS IS" BASIS,
+%% WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+%% See the License for the specific language governing permissions and
+%% limitations under the License.
+
+%%-----------------------------------------------------------------------
+%% File        : typer.erl
+%% Author(s)   : The first version of typer was written by Bingwen He
+%%               with guidance from Kostis Sagonas and Tobias Lindahl.
+%%               Since June 2008 typer is maintained by Kostis Sagonas.
+%% Description : An Erlang/OTP application that shows type information
+%%               for Erlang modules to the user.  Additionally, it can
+%%               annotate the code of files with such type information.
+%%-----------------------------------------------------------------------
+
+-module(typer).
+
+-export([start/0]).
+
+%%-----------------------------------------------------------------------
+
+-define(SHOW, show).
+-define(SHOW_EXPORTED, show_exported).
+-define(ANNOTATE, annotate).
+-define(ANNOTATE_INC_FILES, annotate_inc_files).
+
+-type mode() :: ?SHOW | ?SHOW_EXPORTED | ?ANNOTATE | ?ANNOTATE_INC_FILES.
+
+%%-----------------------------------------------------------------------
+
+-type files()      :: [file:filename()].
+-type callgraph()  :: dialyzer_callgraph:callgraph().
+-type codeserver() :: dialyzer_codeserver:codeserver().
+-type plt()        :: dialyzer_plt:plt().
+
+-record(analysis,
+	{mode				 :: mode() | 'undefined',
+	 macros     = []		 :: [{atom(), term()}],
+	 includes   = []		 :: files(),
+	 codeserver = dialyzer_codeserver:new():: codeserver(),
+	 callgraph  = dialyzer_callgraph:new() :: callgraph(),
+	 files      = []		 :: files(),   % absolute names
+	 plt        = none		 :: 'none' | file:filename(),
+	 no_spec    = false              :: boolean(),
+	 show_succ  = false              :: boolean(),
+	 %% For choosing between specs or edoc @spec comments
+	 edoc       = false		 :: boolean(),
+	 %% Files in 'fms' are compilable with option 'to_pp'; we keep them
+	 %% as {FileName, ModuleName} in case the ModuleName is different
+	 fms        = []		 :: [{file:filename(), module()}],
+	 ex_func    = map__new()	 :: map_dict(),
+	 record     = map__new()	 :: map_dict(),
+	 func       = map__new()	 :: map_dict(),
+	 inc_func   = map__new()	 :: map_dict(),
+	 trust_plt  = dialyzer_plt:new() :: plt()}).
+-type analysis() :: #analysis{}.
+
+-record(args, {files   = [] :: files(),
+	       files_r = [] :: files(),
+	       trusted = [] :: files()}).
+-type args() :: #args{}.
+
+%%--------------------------------------------------------------------
+
+-spec start() -> no_return().
+
+start() ->
+  {Args, Analysis} = process_cl_args(),
+  %% io:format("Args: ~p\n", [Args]),
+  %% io:format("Analysis: ~p\n", [Analysis]),
+  Timer = dialyzer_timing:init(false),
+  TrustedFiles = filter_fd(Args#args.trusted, [], fun is_erl_file/1),
+  Analysis2 = extract(Analysis, TrustedFiles),
+  All_Files = get_all_files(Args),
+  %% io:format("All_Files: ~p\n", [All_Files]),
+  Analysis3 = Analysis2#analysis{files = All_Files},
+  Analysis4 = collect_info(Analysis3),
+  %% io:format("Final: ~p\n", [Analysis4#analysis.fms]),
+  TypeInfo = get_type_info(Analysis4),
+  dialyzer_timing:stop(Timer),
+  show_or_annotate(TypeInfo),
+  %% io:format("\nTyper analysis finished\n"),
+  erlang:halt(0).
+
+%%--------------------------------------------------------------------
+
+-spec extract(analysis(), files()) -> analysis().
+
+extract(#analysis{macros = Macros,
+		  includes = Includes,
+		  trust_plt = TrustPLT} = Analysis, TrustedFiles) ->
+  %% io:format("--- Extracting trusted typer_info... "),
+  Ds = [{d, Name, Value} || {Name, Value} <- Macros],
+  CodeServer = dialyzer_codeserver:new(),
+  Fun =
+    fun(File, CS) ->
+	%% We include one more dir; the one above the one we are trusting
+	%% E.g, for /home/tests/typer_ann/test.ann.erl, we should include
+	%% /home/tests/ rather than /home/tests/typer_ann/
+	AllIncludes = [filename:dirname(filename:dirname(File)) | Includes],
+	Is = [{i, Dir} || Dir <- AllIncludes],
+	CompOpts = dialyzer_utils:src_compiler_opts() ++ Is ++ Ds,
+	case dialyzer_utils:get_abstract_code_from_src(File, CompOpts) of
+	  {ok, AbstractCode} -> 
+	    case dialyzer_utils:get_record_and_type_info(AbstractCode) of
+	      {ok, RecDict} ->
+		Mod = list_to_atom(filename:basename(File, ".erl")),
+		case dialyzer_utils:get_spec_info(Mod, AbstractCode, RecDict) of
+		  {ok, SpecDict, CbDict} ->
+		    CS1 = dialyzer_codeserver:store_temp_records(Mod, RecDict, CS),
+		    dialyzer_codeserver:store_temp_contracts(Mod, SpecDict, CbDict, CS1);
+		  {error, Reason} -> compile_error([Reason])
+		end;
+	      {error, Reason} -> compile_error([Reason])
+	    end;
+	  {error, Reason} -> compile_error(Reason)
+	end
+    end,
+  CodeServer1 = lists:foldl(Fun, CodeServer, TrustedFiles),
+  %% Process remote types
+  NewCodeServer =
+    try
+      CodeServer2 =
+        dialyzer_utils:merge_types(CodeServer1,
+                                   TrustPLT), % XXX change to the PLT?
+      NewExpTypes = dialyzer_codeserver:get_temp_exported_types(CodeServer1),
+      case sets:size(NewExpTypes) of 0 -> ok end,
+      CodeServer3 = dialyzer_codeserver:finalize_exported_types(NewExpTypes, CodeServer2),
+      CodeServer4 = dialyzer_utils:process_record_remote_types(CodeServer3),
+      dialyzer_contracts:process_contract_remote_types(CodeServer4)
+    catch
+      throw:{error, ErrorMsg} ->
+	compile_error(ErrorMsg)
+    end,
+  %% Create TrustPLT
+  ContractsDict = dialyzer_codeserver:get_contracts(NewCodeServer),
+  Contracts = orddict:from_list(dict:to_list(ContractsDict)),
+  NewTrustPLT = dialyzer_plt:insert_contract_list(TrustPLT, Contracts),
+  Analysis#analysis{trust_plt = NewTrustPLT}.
+
+%%--------------------------------------------------------------------
+
+-spec get_type_info(analysis()) -> analysis().
+
+get_type_info(#analysis{callgraph = CallGraph,
+			trust_plt = TrustPLT,
+			codeserver = CodeServer} = Analysis) ->
+  StrippedCallGraph = remove_external(CallGraph, TrustPLT),
+  %% io:format("--- Analyzing callgraph... "),
+  try 
+    NewMiniPlt = dialyzer_succ_typings:analyze_callgraph(StrippedCallGraph,
+                                                         TrustPLT,
+                                                         CodeServer),
+    NewPlt = dialyzer_plt:restore_full_plt(NewMiniPlt),
+    Analysis#analysis{callgraph = StrippedCallGraph, trust_plt = NewPlt}
+  catch
+    error:What ->
+      fatal_error(io_lib:format("Analysis failed with message: ~p", 
+				[{What, erlang:get_stacktrace()}]));
+    throw:{dialyzer_succ_typing_error, Msg} ->
+      fatal_error(io_lib:format("Analysis failed with message: ~s", [Msg]))
+  end.
+
+-spec remove_external(callgraph(), plt()) -> callgraph().
+
+remove_external(CallGraph, PLT) ->
+  {StrippedCG0, Ext} = dialyzer_callgraph:remove_external(CallGraph),
+  case get_external(Ext, PLT) of
+    [] -> ok;
+    Externals ->
+      msg(io_lib:format(" Unknown functions: ~p\n", [lists:usort(Externals)])),
+      ExtTypes = rcv_ext_types(),
+      case ExtTypes of
+        [] -> ok;
+        _ -> msg(io_lib:format(" Unknown types: ~p\n", [ExtTypes]))
+      end
+  end,
+  StrippedCG0.
+
+-spec get_external([{mfa(), mfa()}], plt()) -> [mfa()].
+
+get_external(Exts, Plt) ->
+  Fun = fun ({_From, To = {M, F, A}}, Acc) ->
+	    case dialyzer_plt:contains_mfa(Plt, To) of
+	      false ->
+		case erl_bif_types:is_known(M, F, A) of
+		  true -> Acc;
+		  false -> [To|Acc]
+		end;
+	      true -> Acc
+	    end
+	end,
+  lists:foldl(Fun, [], Exts).
+
+%%--------------------------------------------------------------------
+%% Showing type information or annotating files with such information.
+%%--------------------------------------------------------------------
+
+-define(TYPER_ANN_DIR, "typer_ann").
+
+-type line()      :: non_neg_integer().
+-type fa()        :: {atom(), arity()}.
+-type func_info() :: {line(), atom(), arity()}.
+
+-record(info, {records = maps:new() :: erl_types:type_table(),
+	       functions = []       :: [func_info()],
+	       types = map__new()   :: map_dict(),
+	       edoc = false	    :: boolean()}).
+-record(inc, {map = map__new() :: map_dict(), filter = [] :: files()}).
+-type inc() :: #inc{}.
+
+-spec show_or_annotate(analysis()) -> 'ok'.
+
+show_or_annotate(#analysis{mode = Mode, fms = Files} = Analysis) ->
+  case Mode of
+    ?SHOW -> show(Analysis);
+    ?SHOW_EXPORTED -> show(Analysis);
+    ?ANNOTATE ->
+      Fun = fun ({File, Module}) ->
+		Info = get_final_info(File, Module, Analysis),
+		write_typed_file(File, Info)
+	    end,
+      lists:foreach(Fun, Files);
+    ?ANNOTATE_INC_FILES ->
+      IncInfo = write_and_collect_inc_info(Analysis),
+      write_inc_files(IncInfo)
+  end.
+
+write_and_collect_inc_info(Analysis) ->
+  Fun = fun ({File, Module}, Inc) ->
+	    Info = get_final_info(File, Module, Analysis),
+	    write_typed_file(File, Info),
+	    IncFuns = get_functions(File, Analysis),
+	    collect_imported_functions(IncFuns, Info#info.types, Inc)
+	end,
+  NewInc = lists:foldl(Fun, #inc{}, Analysis#analysis.fms),
+  clean_inc(NewInc).
+
+write_inc_files(Inc) ->
+  Fun =
+    fun (File) ->
+	Val = map__lookup(File, Inc#inc.map),
+	%% Val is function with its type info
+	%% in form [{{Line,F,A},Type}]
+	Functions = [Key || {Key, _} <- Val],
+	Val1 = [{{F,A},Type} || {{_Line,F,A},Type} <- Val],
+	Info = #info{types = map__from_list(Val1),
+		     records = maps:new(),
+		     %% Note we need to sort functions here!
+		     functions = lists:keysort(1, Functions)},
+	%% io:format("Types ~p\n", [Info#info.types]),
+	%% io:format("Functions ~p\n", [Info#info.functions]),
+	%% io:format("Records ~p\n", [Info#info.records]),
+	write_typed_file(File, Info)
+    end,
+  lists:foreach(Fun, dict:fetch_keys(Inc#inc.map)).
+
+show(Analysis) ->
+  Fun = fun ({File, Module}) ->
+	    Info = get_final_info(File, Module, Analysis),
+	    show_type_info(File, Info)
+	end,
+  lists:foreach(Fun, Analysis#analysis.fms).
+
+get_final_info(File, Module, Analysis) ->
+  Records = get_records(File, Analysis),
+  Types = get_types(Module, Analysis, Records),
+  Functions = get_functions(File, Analysis),
+  Edoc = Analysis#analysis.edoc,
+  #info{records = Records, functions = Functions, types = Types, edoc = Edoc}.
+
+collect_imported_functions(Functions, Types, Inc) ->
+  %% Coming from other sourses, including:
+  %% FIXME: How to deal with yecc-generated file????
+  %%     --.yrl (yecc-generated file)???
+  %%     -- yeccpre.hrl (yecc-generated file)???
+  %%     -- other cases
+  Fun = fun ({File, _} = Obj, I) ->
+	    case is_yecc_gen(File, I) of
+	      {true, NewI} -> NewI;
+	      {false, NewI} ->
+		check_imported_functions(Obj, NewI, Types)
+	    end
+	end,
+  lists:foldl(Fun, Inc, Functions).
+
+-spec is_yecc_gen(file:filename(), inc()) -> {boolean(), inc()}.
+
+is_yecc_gen(File, #inc{filter = Fs} = Inc) ->
+  case lists:member(File, Fs) of
+    true -> {true, Inc};
+    false ->
+      case filename:extension(File) of
+	".yrl" ->
+	  Rootname = filename:rootname(File, ".yrl"),
+	  Obj = Rootname ++ ".erl",
+	  case lists:member(Obj, Fs) of
+	    true -> {true, Inc};
+	    false ->
+	      NewInc = Inc#inc{filter = [Obj|Fs]},
+	      {true, NewInc}
+	  end;
+	_ ->
+	  case filename:basename(File) of
+	    "yeccpre.hrl" -> {true, Inc};
+	    _ -> {false, Inc}
+	  end
+      end
+  end.
+
+check_imported_functions({File, {Line, F, A}}, Inc, Types) ->
+  IncMap = Inc#inc.map,
+  FA = {F, A},
+  Type = get_type_info(FA, Types),
+  case map__lookup(File, IncMap) of
+    none -> %% File is not added. Add it
+      Obj = {File,[{FA, {Line, Type}}]},
+      NewMap = map__insert(Obj, IncMap),
+      Inc#inc{map = NewMap};
+    Val -> %% File is already in. Check.
+      case lists:keyfind(FA, 1, Val) of
+	false ->
+	  %% Function is not in; add it
+	  Obj = {File, Val ++ [{FA, {Line, Type}}]},
+	  NewMap = map__insert(Obj, IncMap),
+	  Inc#inc{map = NewMap};
+	Type ->
+	  %% Function is in and with same type
+	  Inc;
+	_ ->
+	  %% Function is in but with diff type
+	  inc_warning(FA, File),
+	  Elem = lists:keydelete(FA, 1, Val),
+	  NewMap = case Elem of
+		     [] -> map__remove(File, IncMap);
+		     _  -> map__insert({File, Elem}, IncMap)
+		   end,
+	  Inc#inc{map = NewMap}
+      end
+  end.
+
+inc_warning({F, A}, File) ->
+  io:format("      ***Warning: Skip function ~p/~p ", [F, A]),
+  io:format("in file ~p because of inconsistent type\n", [File]).
+
+clean_inc(Inc) ->
+  Inc1 = remove_yecc_generated_file(Inc),
+  normalize_obj(Inc1).
+
+remove_yecc_generated_file(#inc{filter = Filter} = Inc) ->
+  Fun = fun (Key, #inc{map = Map} = I) ->
+	    I#inc{map = map__remove(Key, Map)}
+	end,
+  lists:foldl(Fun, Inc, Filter).
+
+normalize_obj(TmpInc) ->
+  Fun = fun (Key, Val, Inc) ->
+	    NewVal = [{{Line,F,A},Type} || {{F,A},{Line,Type}} <- Val],
+	    map__insert({Key, NewVal}, Inc)
+	end,
+  TmpInc#inc{map = map__fold(Fun, map__new(), TmpInc#inc.map)}.
+
+get_records(File, Analysis) ->
+  map__lookup(File, Analysis#analysis.record).
+
+get_types(Module, Analysis, Records) ->
+  TypeInfoPlt = Analysis#analysis.trust_plt,
+  TypeInfo = 
+    case dialyzer_plt:lookup_module(TypeInfoPlt, Module) of
+      none -> [];
+      {value, List} -> List
+    end,
+  CodeServer = Analysis#analysis.codeserver,
+  TypeInfoList =
+    case Analysis#analysis.show_succ of
+      true ->
+	[convert_type_info(I) || I <- TypeInfo];
+      false ->
+	[get_type(I, CodeServer, Records) || I <- TypeInfo]
+    end,
+  map__from_list(TypeInfoList).
+
+convert_type_info({{_M, F, A}, Range, Arg}) ->
+  {{F, A}, {Range, Arg}}.
+
+get_type({{M, F, A} = MFA, Range, Arg}, CodeServer, Records) ->
+  case dialyzer_codeserver:lookup_mfa_contract(MFA, CodeServer) of
+    error ->
+      {{F, A}, {Range, Arg}};
+    {ok, {_FileLine, Contract, _Xtra}} ->
+      Sig = erl_types:t_fun(Arg, Range),
+      case dialyzer_contracts:check_contract(Contract, Sig) of
+	ok -> {{F, A}, {contract, Contract}};
+	{error, {extra_range, _, _}} ->
+	  {{F, A}, {contract, Contract}};
+	{error, {overlapping_contract, []}} ->
+	  {{F, A}, {contract, Contract}};
+	{error, invalid_contract} ->
+	  CString = dialyzer_contracts:contract_to_string(Contract),
+	  SigString = dialyzer_utils:format_sig(Sig, Records),
+	  Msg = io_lib:format("Error in contract of function ~w:~w/~w\n" 
+			      "\t The contract is: " ++ CString ++ "\n" ++
+			      "\t but the inferred signature is: ~s",
+			      [M, F, A, SigString]),
+	  fatal_error(Msg);
+	{error, ErrorStr} when is_list(ErrorStr) -> % ErrorStr is a string()
+	  Msg = io_lib:format("Error in contract of function ~w:~w/~w: ~s",
+			      [M, F, A, ErrorStr]),
+	  fatal_error(Msg)
+      end
+  end.
+
+get_functions(File, Analysis) ->
+  case Analysis#analysis.mode of
+    ?SHOW ->
+      Funcs = map__lookup(File, Analysis#analysis.func),
+      Inc_Funcs = map__lookup(File, Analysis#analysis.inc_func),
+      remove_module_info(Funcs) ++ normalize_incFuncs(Inc_Funcs);
+    ?SHOW_EXPORTED ->
+      Ex_Funcs = map__lookup(File, Analysis#analysis.ex_func),
+      remove_module_info(Ex_Funcs);
+    ?ANNOTATE ->
+      Funcs = map__lookup(File, Analysis#analysis.func),
+      remove_module_info(Funcs);
+    ?ANNOTATE_INC_FILES ->
+      map__lookup(File, Analysis#analysis.inc_func)
+  end.
+
+normalize_incFuncs(Functions) ->
+  [FunInfo || {_FileName, FunInfo} <- Functions].
+
+-spec remove_module_info([func_info()]) -> [func_info()].
+
+remove_module_info(FunInfoList) ->
+  F = fun ({_,module_info,0}) -> false;
+	  ({_,module_info,1}) -> false;
+	  ({Line,F,A}) when is_integer(Line), is_atom(F), is_integer(A) -> true
+      end,
+  lists:filter(F, FunInfoList).
+
+write_typed_file(File, Info) ->
+  io:format("      Processing file: ~p\n", [File]),
+  Dir = filename:dirname(File),
+  RootName = filename:basename(filename:rootname(File)),
+  Ext = filename:extension(File),
+  TyperAnnDir = filename:join(Dir, ?TYPER_ANN_DIR),
+  TmpNewFilename = lists:concat([RootName, ".ann", Ext]),
+  NewFileName = filename:join(TyperAnnDir, TmpNewFilename),
+  case file:make_dir(TyperAnnDir) of
+    {error, Reason} ->
+      case Reason of
+	eexist -> %% TypEr dir exists; remove old typer files if they exist
+	  case file:delete(NewFileName) of
+	    ok -> ok;
+	    {error, enoent} -> ok;
+	    {error, _} ->
+	      Msg = io_lib:format("Error in deleting file ~s\n", [NewFileName]),
+	      fatal_error(Msg)
+	  end,
+	  write_typed_file(File, Info, NewFileName);
+	enospc ->
+	  Msg = io_lib:format("Not enough space in ~p\n", [Dir]),
+	  fatal_error(Msg);
+	eacces ->
+	  Msg = io_lib:format("No write permission in ~p\n", [Dir]),
+	  fatal_error(Msg);
+	_ ->
+	  Msg = io_lib:format("Unhandled error ~s when writing ~p\n",
+			      [Reason, Dir]),
+	  fatal_error(Msg)
+      end;
+    ok -> %% Typer dir does NOT exist
+      write_typed_file(File, Info, NewFileName)
+  end.
+
+write_typed_file(File, Info, NewFileName) ->
+  {ok, Binary} = file:read_file(File),
+  Chars = binary_to_list(Binary),
+  write_typed_file(Chars, NewFileName, Info, 1, []),
+  io:format("             Saved as: ~p\n", [NewFileName]).
+
+write_typed_file(Chars, File, #info{functions = []}, _LNo, _Acc) ->
+  ok = file:write_file(File, list_to_binary(Chars), [append]);
+write_typed_file([Ch|Chs] = Chars, File, Info, LineNo, Acc) ->
+  [{Line,F,A}|RestFuncs] = Info#info.functions,
+  case Line of
+    1 -> %% This will happen only for inc files
+      ok = raw_write(F, A, Info, File, []),
+      NewInfo = Info#info{functions = RestFuncs},
+      NewAcc = [],
+      write_typed_file(Chars, File, NewInfo, Line, NewAcc);
+    _ ->
+      case Ch of
+	10 ->
+	  NewLineNo = LineNo + 1,
+	  {NewInfo, NewAcc} =
+	    case NewLineNo of
+	      Line ->
+		ok = raw_write(F, A, Info, File, [Ch|Acc]),
+		{Info#info{functions = RestFuncs}, []};
+	      _ ->
+		{Info, [Ch|Acc]}
+	    end,
+	  write_typed_file(Chs, File, NewInfo, NewLineNo, NewAcc);
+	_ ->
+	  write_typed_file(Chs, File, Info, LineNo, [Ch|Acc])
+      end
+  end.
+
+raw_write(F, A, Info, File, Content) ->
+  TypeInfo = get_type_string(F, A, Info, file),
+  ContentList = lists:reverse(Content) ++ TypeInfo ++ "\n",
+  ContentBin = list_to_binary(ContentList),
+  file:write_file(File, ContentBin, [append]).
+
+get_type_string(F, A, Info, Mode) ->
+  Type = get_type_info({F,A}, Info#info.types),
+  TypeStr =
+    case Type of
+      {contract, C} -> 
+        dialyzer_contracts:contract_to_string(C);
+      {RetType, ArgType} ->
+	Sig = erl_types:t_fun(ArgType, RetType),
+        dialyzer_utils:format_sig(Sig, Info#info.records)
+    end,
+  case Info#info.edoc of
+    false ->
+      case {Mode, Type} of
+	{file, {contract, _}} -> "";
+	_ ->
+	  Prefix = lists:concat(["-spec ", erl_types:atom_to_string(F)]),
+	  lists:concat([Prefix, TypeStr, "."])
+      end;
+    true ->
+      Prefix = lists:concat(["%% @spec ", F]),
+      lists:concat([Prefix, TypeStr, "."])
+  end.
+ 
+show_type_info(File, Info) ->
+  io:format("\n%% File: ~p\n%% ", [File]),
+  OutputString = lists:concat(["~.", length(File)+8, "c~n"]),
+  io:fwrite(OutputString, [$-]),
+  Fun = fun ({_LineNo, F, A}) ->
+	    TypeInfo = get_type_string(F, A, Info, show),
+	    io:format("~s\n", [TypeInfo])
+	end,
+  lists:foreach(Fun, Info#info.functions).
+
+get_type_info(Func, Types) ->
+  case map__lookup(Func, Types) of
+    none ->
+      %% Note: Typeinfo of any function should exist in
+      %% the result offered by dialyzer, otherwise there 
+      %% *must* be something wrong with the analysis
+      Msg = io_lib:format("No type info for function: ~p\n", [Func]),
+      fatal_error(Msg);
+    {contract, _Fun} = C -> C;
+    {_RetType, _ArgType} = RA -> RA 
+  end.
+
+%%--------------------------------------------------------------------
+%% Processing of command-line options and arguments.
+%%--------------------------------------------------------------------
+
+-spec process_cl_args() -> {args(), analysis()}.
+
+process_cl_args() ->
+  ArgList = init:get_plain_arguments(),
+  %% io:format("Args is ~p\n", [ArgList]),
+  {Args, Analysis} = analyze_args(ArgList, #args{}, #analysis{}),
+  %% if the mode has not been set, set it to the default mode (show)
+  {Args, case Analysis#analysis.mode of
+	   undefined -> Analysis#analysis{mode = ?SHOW};
+	   Mode when is_atom(Mode) -> Analysis
+	 end}.
+
+analyze_args([], Args, Analysis) ->
+  {Args, Analysis};
+analyze_args(ArgList, Args, Analysis) ->
+  {Result, Rest} = cl(ArgList),
+  {NewArgs, NewAnalysis} = analyze_result(Result, Args, Analysis),
+  analyze_args(Rest, NewArgs, NewAnalysis).
+
+cl(["-h"|_])     -> help_message();
+cl(["--help"|_]) -> help_message();
+cl(["-v"|_])        -> version_message();
+cl(["--version"|_]) -> version_message();
+cl(["--edoc"|Opts]) -> {edoc, Opts};
+cl(["--show"|Opts]) -> {{mode, ?SHOW}, Opts};
+cl(["--show_exported"|Opts]) -> {{mode, ?SHOW_EXPORTED}, Opts};
+cl(["--show-exported"|Opts]) -> {{mode, ?SHOW_EXPORTED}, Opts};
+cl(["--show_success_typings"|Opts]) -> {show_succ, Opts};
+cl(["--show-success-typings"|Opts]) -> {show_succ, Opts};
+cl(["--annotate"|Opts]) -> {{mode, ?ANNOTATE}, Opts};
+cl(["--annotate-inc-files"|Opts]) -> {{mode, ?ANNOTATE_INC_FILES}, Opts};
+cl(["--no_spec"|Opts]) -> {no_spec, Opts};
+cl(["--plt",Plt|Opts]) -> {{plt, Plt}, Opts};
+cl(["-D"++Def|Opts]) ->
+  case Def of
+    "" -> fatal_error("no variable name specified after -D");
+    _ ->
+      DefPair = process_def_list(re:split(Def, "=", [{return, list}])),
+      {{def, DefPair}, Opts}
+  end;
+cl(["-I",Dir|Opts]) -> {{inc, Dir}, Opts};
+cl(["-I"++Dir|Opts]) ->
+  case Dir of
+    "" -> fatal_error("no include directory specified after -I");
+    _ -> {{inc, Dir}, Opts}
+  end;
+cl(["-T"|Opts]) ->
+  {Files, RestOpts} = dialyzer_cl_parse:collect_args(Opts),
+  case Files of
+    [] -> fatal_error("no file or directory specified after -T");
+    [_|_] -> {{trusted, Files}, RestOpts}
+  end;
+cl(["-r"|Opts]) ->
+  {Files, RestOpts} = dialyzer_cl_parse:collect_args(Opts),
+  {{files_r, Files}, RestOpts};
+cl(["-pa",Dir|Opts]) -> {{pa,Dir}, Opts};
+cl(["-pz",Dir|Opts]) -> {{pz,Dir}, Opts};
+cl(["-"++H|_]) -> fatal_error("unknown option -"++H);
+cl(Opts) -> 
+  {Files, RestOpts} = dialyzer_cl_parse:collect_args(Opts),
+  {{files, Files}, RestOpts}.
+
+process_def_list(L) ->
+  case L of
+    [Name, Value] ->
+      {ok, Tokens, _} = erl_scan:string(Value ++ "."),
+      {ok, ErlValue} = erl_parse:parse_term(Tokens),
+      {list_to_atom(Name), ErlValue};
+    [Name] ->
+      {list_to_atom(Name), true}
+  end.
+
+%% Get information about files that the user trusts and wants to analyze
+analyze_result({files, Val}, Args, Analysis) ->
+  NewVal = Args#args.files ++ Val,
+  {Args#args{files = NewVal}, Analysis};
+analyze_result({files_r, Val}, Args, Analysis) ->
+  NewVal = Args#args.files_r ++ Val,
+  {Args#args{files_r = NewVal}, Analysis};
+analyze_result({trusted, Val}, Args, Analysis) ->
+  NewVal = Args#args.trusted ++ Val,
+  {Args#args{trusted = NewVal}, Analysis};
+analyze_result(edoc, Args, Analysis) ->
+  {Args, Analysis#analysis{edoc = true}};
+%% Get useful information for actual analysis
+analyze_result({mode, Mode}, Args, Analysis) ->
+  case Analysis#analysis.mode of
+    undefined -> {Args, Analysis#analysis{mode = Mode}};
+    OldMode -> mode_error(OldMode, Mode)
+  end;
+analyze_result({def, Val}, Args, Analysis) ->
+  NewVal = Analysis#analysis.macros ++ [Val],
+  {Args, Analysis#analysis{macros = NewVal}};
+analyze_result({inc, Val}, Args, Analysis) ->
+  NewVal = Analysis#analysis.includes ++ [Val],
+  {Args, Analysis#analysis{includes = NewVal}};
+analyze_result({plt, Plt}, Args, Analysis) ->
+  {Args, Analysis#analysis{plt = Plt}};
+analyze_result(show_succ, Args, Analysis) ->
+  {Args, Analysis#analysis{show_succ = true}};
+analyze_result(no_spec, Args, Analysis) ->
+  {Args, Analysis#analysis{no_spec = true}};
+analyze_result({pa, Dir}, Args, Analysis) ->
+  true = code:add_patha(Dir),
+  {Args, Analysis};
+analyze_result({pz, Dir}, Args, Analysis) ->
+  true = code:add_pathz(Dir),
+  {Args, Analysis}.
+
+%%--------------------------------------------------------------------
+%% File processing.
+%%--------------------------------------------------------------------
+
+-spec get_all_files(args()) -> [file:filename(),...].
+
+get_all_files(#args{files = Fs, files_r = Ds}) ->
+  case filter_fd(Fs, Ds, fun test_erl_file_exclude_ann/1) of
+    [] -> fatal_error("no file(s) to analyze");
+    AllFiles -> AllFiles
+  end.
+
+-spec test_erl_file_exclude_ann(file:filename()) -> boolean().
+
+test_erl_file_exclude_ann(File) ->
+  case is_erl_file(File) of
+    true -> %% Exclude files ending with ".ann.erl"
+      case re:run(File, "[\.]ann[\.]erl$") of
+	{match, _} -> false;
+	nomatch -> true
+      end;
+    false -> false
+  end.
+
+-spec is_erl_file(file:filename()) -> boolean().
+
+is_erl_file(File) ->
+  filename:extension(File) =:= ".erl".
+
+-type test_file_fun() :: fun((file:filename()) -> boolean()).
+
+-spec filter_fd(files(), files(), test_file_fun()) -> files().
+
+filter_fd(File_Dir, Dir_R, Fun) ->
+  All_File_1 = process_file_and_dir(File_Dir, Fun),
+  All_File_2 = process_dir_rec(Dir_R, Fun),
+  remove_dup(All_File_1 ++ All_File_2).
+
+-spec process_file_and_dir(files(), test_file_fun()) -> files().
+
+process_file_and_dir(File_Dir, TestFun) ->
+  Fun =
+    fun (Elem, Acc) ->
+	case filelib:is_regular(Elem) of
+	  true  -> process_file(Elem, TestFun, Acc);
+	  false -> check_dir(Elem, false, Acc, TestFun)
+	end
+    end,
+  lists:foldl(Fun, [], File_Dir).
+
+-spec process_dir_rec(files(), test_file_fun()) -> files().
+
+process_dir_rec(Dirs, TestFun) ->
+  Fun = fun (Dir, Acc) -> check_dir(Dir, true, Acc, TestFun) end,
+  lists:foldl(Fun, [], Dirs).
+
+-spec check_dir(file:filename(), boolean(), files(), test_file_fun()) -> files().
+
+check_dir(Dir, Recursive, Acc, Fun) ->
+  case file:list_dir(Dir) of
+    {ok, Files} ->
+      {TmpDirs, TmpFiles} = split_dirs_and_files(Files, Dir),
+      case Recursive of
+	false ->
+	  FinalFiles = process_file_and_dir(TmpFiles, Fun),
+	  Acc ++ FinalFiles;
+	true ->
+	  TmpAcc1 = process_file_and_dir(TmpFiles, Fun),
+	  TmpAcc2 = process_dir_rec(TmpDirs, Fun),
+	  Acc ++ TmpAcc1 ++ TmpAcc2
+      end;
+    {error, eacces} ->
+      fatal_error("no access permission to dir \""++Dir++"\"");
+    {error, enoent} ->
+      fatal_error("cannot access "++Dir++": No such file or directory");
+    {error, _Reason} ->
+      fatal_error("error involving a use of file:list_dir/1")
+  end.
+
+%% Same order as the input list
+-spec process_file(file:filename(), test_file_fun(), files()) -> files().
+
+process_file(File, TestFun, Acc) ->
+  case TestFun(File) of
+    true  -> Acc ++ [File];
+    false -> Acc
+  end.
+
+%% Same order as the input list
+-spec split_dirs_and_files(files(), file:filename()) -> {files(), files()}.
+
+split_dirs_and_files(Elems, Dir) ->
+  Test_Fun =
+    fun (Elem, {DirAcc, FileAcc}) ->
+	File = filename:join(Dir, Elem),
+	case filelib:is_regular(File) of
+	  false -> {[File|DirAcc], FileAcc}; 
+	  true  -> {DirAcc, [File|FileAcc]}
+	end
+    end,
+  {Dirs, Files} = lists:foldl(Test_Fun, {[], []}, Elems),
+  {lists:reverse(Dirs), lists:reverse(Files)}.  
+
+%% Removes duplicate filenames but keeps the order of the input list
+-spec remove_dup(files()) -> files().
+
+remove_dup(Files) ->
+  Test_Dup = fun (File, Acc) ->
+		 case lists:member(File, Acc) of
+		   true  -> Acc;
+		   false -> [File|Acc]
+		 end
+	     end,
+  Reversed_Elems = lists:foldl(Test_Dup, [], Files),
+  lists:reverse(Reversed_Elems).
+
+%%--------------------------------------------------------------------
+%% Collect information.
+%%--------------------------------------------------------------------
+
+-type inc_file_info() :: {file:filename(), func_info()}.
+
+-record(tmpAcc, {file		  :: file:filename(),
+		 module		  :: atom(),
+		 funcAcc = []	  :: [func_info()],
+		 incFuncAcc = []  :: [inc_file_info()],
+		 dialyzerObj = [] :: [{mfa(), {_, _}}]}).
+
+-spec collect_info(analysis()) -> analysis().
+
+collect_info(Analysis) ->
+  NewPlt =
+    try get_dialyzer_plt(Analysis) of
+	DialyzerPlt ->
+	dialyzer_plt:merge_plts([Analysis#analysis.trust_plt, DialyzerPlt])
+    catch
+      throw:{dialyzer_error,_Reason} ->
+	fatal_error("Dialyzer's PLT is missing or is not up-to-date; please (re)create it")
+    end,
+  NewAnalysis = lists:foldl(fun collect_one_file_info/2, 
+			    Analysis#analysis{trust_plt = NewPlt}, 
+			    Analysis#analysis.files),
+  %% Process Remote Types
+  TmpCServer = NewAnalysis#analysis.codeserver,
+  NewCServer =
+    try
+      TmpCServer1 = dialyzer_utils:merge_types(TmpCServer, NewPlt),
+      NewExpTypes = dialyzer_codeserver:get_temp_exported_types(TmpCServer),
+      OldExpTypes = dialyzer_plt:get_exported_types(NewPlt),
+      MergedExpTypes = sets:union(NewExpTypes, OldExpTypes),
+      TmpCServer2 =
+        dialyzer_codeserver:finalize_exported_types(MergedExpTypes, TmpCServer1),
+      TmpCServer3 = dialyzer_utils:process_record_remote_types(TmpCServer2),
+      dialyzer_contracts:process_contract_remote_types(TmpCServer3)
+    catch
+      throw:{error, ErrorMsg} ->
+	fatal_error(ErrorMsg)
+    end,
+  NewAnalysis#analysis{codeserver = NewCServer}.
+
+collect_one_file_info(File, Analysis) ->
+  Ds = [{d,Name,Val} || {Name,Val} <- Analysis#analysis.macros],
+  %% Current directory should also be included in "Includes".
+  Includes = [filename:dirname(File)|Analysis#analysis.includes],
+  Is = [{i,Dir} || Dir <- Includes],
+  Options = dialyzer_utils:src_compiler_opts() ++ Is ++ Ds,
+  case dialyzer_utils:get_abstract_code_from_src(File, Options) of
+    {error, Reason} ->
+      %% io:format("File=~p\n,Options=~p\n,Error=~p\n", [File,Options,Reason]),
+      compile_error(Reason);
+    {ok, AbstractCode} ->
+      case dialyzer_utils:get_core_from_abstract_code(AbstractCode, Options) of
+	error -> compile_error(["Could not get core erlang for "++File]);
+	{ok, Core} ->
+	  case dialyzer_utils:get_record_and_type_info(AbstractCode) of
+	    {error, Reason} -> compile_error([Reason]);
+	    {ok, Records} ->
+	      Mod = cerl:concrete(cerl:module_name(Core)),
+	      case dialyzer_utils:get_spec_info(Mod, AbstractCode, Records) of
+		{error, Reason} -> compile_error([Reason]);
+		{ok, SpecInfo, CbInfo} ->
+                  ExpTypes = get_exported_types_from_core(Core),
+		  analyze_core_tree(Core, Records, SpecInfo, CbInfo,
+				    ExpTypes, Analysis, File)
+	      end
+	  end
+      end
+  end.
+
+analyze_core_tree(Core, Records, SpecInfo, CbInfo, ExpTypes, Analysis, File) ->
+  Module = cerl:concrete(cerl:module_name(Core)),
+  TmpTree = cerl:from_records(Core),
+  CS1 = Analysis#analysis.codeserver,
+  NextLabel = dialyzer_codeserver:get_next_core_label(CS1),
+  {Tree, NewLabel} = cerl_trees:label(TmpTree, NextLabel),
+  CS2 = dialyzer_codeserver:insert(Module, Tree, CS1),
+  CS3 = dialyzer_codeserver:set_next_core_label(NewLabel, CS2),
+  CS4 = dialyzer_codeserver:store_temp_records(Module, Records, CS3),
+  CS5 =
+    case Analysis#analysis.no_spec of
+      true -> CS4;
+      false ->
+	dialyzer_codeserver:store_temp_contracts(Module, SpecInfo, CbInfo, CS4)
+    end,
+  OldExpTypes = dialyzer_codeserver:get_temp_exported_types(CS5),
+  MergedExpTypes = sets:union(ExpTypes, OldExpTypes),
+  CS6 = dialyzer_codeserver:insert_temp_exported_types(MergedExpTypes, CS5),
+  Ex_Funcs = [{0,F,A} || {_,_,{F,A}} <- cerl:module_exports(Tree)],
+  CG = Analysis#analysis.callgraph,
+  {V, E} = dialyzer_callgraph:scan_core_tree(Tree, CG),
+  dialyzer_callgraph:add_edges(E, V, CG),
+  Fun = fun analyze_one_function/2,
+  All_Defs = cerl:module_defs(Tree),
+  Acc = lists:foldl(Fun, #tmpAcc{file = File, module = Module}, All_Defs),
+  Exported_FuncMap = map__insert({File, Ex_Funcs}, Analysis#analysis.ex_func),
+  %% we must sort all functions in the file which
+  %% originate from this file by *numerical order* of lineNo
+  Sorted_Functions = lists:keysort(1, Acc#tmpAcc.funcAcc),
+  FuncMap = map__insert({File, Sorted_Functions}, Analysis#analysis.func),
+  %% we do not need to sort functions which are imported from included files
+  IncFuncMap = map__insert({File, Acc#tmpAcc.incFuncAcc},
+			   Analysis#analysis.inc_func),
+  FMs = Analysis#analysis.fms ++ [{File, Module}],
+  RecordMap = map__insert({File, Records}, Analysis#analysis.record),
+  Analysis#analysis{fms = FMs,
+		    callgraph = CG,
+		    codeserver = CS6,
+		    ex_func = Exported_FuncMap,
+		    inc_func = IncFuncMap,
+		    record = RecordMap,
+		    func = FuncMap}.
+
+analyze_one_function({Var, FunBody} = Function, Acc) ->
+  F = cerl:fname_id(Var),
+  A = cerl:fname_arity(Var),
+  TmpDialyzerObj = {{Acc#tmpAcc.module, F, A}, Function},
+  NewDialyzerObj = Acc#tmpAcc.dialyzerObj ++ [TmpDialyzerObj],  
+  Anno = cerl:get_ann(FunBody),
+  LineNo = get_line(Anno),
+  FileName = get_file(Anno),
+  BaseName = filename:basename(FileName),
+  FuncInfo = {LineNo, F, A},
+  OriginalName = Acc#tmpAcc.file,
+  {FuncAcc, IncFuncAcc} =
+    case (FileName =:= OriginalName) orelse (BaseName =:= OriginalName) of
+      true -> %% Coming from original file
+	%% io:format("Added function ~p\n", [{LineNo, F, A}]),
+	{Acc#tmpAcc.funcAcc ++ [FuncInfo], Acc#tmpAcc.incFuncAcc};
+      false ->
+	%% Coming from other sourses, including:
+	%%     -- .yrl (yecc-generated file)
+	%%     -- yeccpre.hrl (yecc-generated file)
+	%%     -- other cases
+	{Acc#tmpAcc.funcAcc, Acc#tmpAcc.incFuncAcc ++ [{FileName, FuncInfo}]}
+    end,
+  Acc#tmpAcc{funcAcc = FuncAcc,
+	     incFuncAcc = IncFuncAcc,
+	     dialyzerObj = NewDialyzerObj}.
+
+get_line([Line|_]) when is_integer(Line) -> Line;
+get_line([_|T]) -> get_line(T);
+get_line([]) -> none.
+
+get_file([{file,File}|_]) -> File;
+get_file([_|T]) -> get_file(T);
+get_file([]) -> "no_file". % should not happen
+
+-spec get_dialyzer_plt(analysis()) -> plt().
+
+get_dialyzer_plt(#analysis{plt = PltFile0}) ->
+  PltFile =
+    case PltFile0 =:= none of
+      true -> dialyzer_plt:get_default_plt();
+      false -> PltFile0
+    end,
+  dialyzer_plt:from_file(PltFile).
+
+%% Exported Types
+
+get_exported_types_from_core(Core) ->
+  Attrs = cerl:module_attrs(Core),
+  ExpTypes1 = [cerl:concrete(L2) || {L1, L2} <- Attrs,
+                                    cerl:is_literal(L1),
+                                    cerl:is_literal(L2),
+                                    cerl:concrete(L1) =:= 'export_type'],
+  ExpTypes2 = lists:flatten(ExpTypes1),
+  M = cerl:atom_val(cerl:module_name(Core)),
+  sets:from_list([{M, F, A} || {F, A} <- ExpTypes2]).
+
+%%--------------------------------------------------------------------
+%% Utilities for error reporting.
+%%--------------------------------------------------------------------
+
+-spec fatal_error(string()) -> no_return().
+
+fatal_error(Slogan) ->
+  msg(io_lib:format("typer: ~s\n", [Slogan])),
+  erlang:halt(1).
+
+-spec mode_error(mode(), mode()) -> no_return().
+
+mode_error(OldMode, NewMode) ->
+  Msg = io_lib:format("Mode was previously set to '~s'; "
+		      "can not set it to '~s' now",
+		      [OldMode, NewMode]),
+  fatal_error(Msg).
+
+-spec compile_error([string()]) -> no_return().
+
+compile_error(Reason) ->
+  JoinedString = lists:flatten([X ++ "\n" || X <- Reason]),
+  Msg = "Analysis failed with error report:\n" ++ JoinedString,
+  fatal_error(Msg).
+
+-spec msg(string()) -> 'ok'.
+
+msg(Msg) ->
+  io:format(standard_error, "~s", [Msg]).
+
+%%--------------------------------------------------------------------
+%% Version and help messages.
+%%--------------------------------------------------------------------
+
+-spec version_message() -> no_return().
+
+version_message() ->
+  io:format("TypEr version "++?VSN++"\n"),
+  erlang:halt(0).
+
+-spec help_message() -> no_return().
+
+help_message() ->
+  S = <<" Usage: typer [--help] [--version] [--plt PLT] [--edoc]
+              [--show | --show-exported | --annotate | --annotate-inc-files]
+              [-Ddefine]* [-I include_dir]* [-pa dir]* [-pz dir]*
+              [-T application]* [-r] file*
+
+ Options:
+   -r dir*
+       search directories recursively for .erl files below them
+   --show
+       Prints type specifications for all functions on stdout.
+       (this is the default behaviour; this option is not really needed)
+   --show-exported (or --show_exported)
+       Same as --show, but prints specifications for exported functions only
+       Specs are displayed sorted alphabetically on the function's name
+   --annotate
+       Annotates the specified files with type specifications
+   --annotate-inc-files
+       Same as --annotate but annotates all -include() files as well as
+       all .erl files (use this option with caution - has not been tested much)
+   --edoc
+       Prints type information as Edoc @spec comments, not as type specs
+   --plt PLT
+       Use the specified dialyzer PLT file rather than the default one
+   -T file*
+       The specified file(s) already contain type specifications and these
+       are to be trusted in order to print specs for the rest of the files
+       (Multiple files or dirs, separated by spaces, can be specified.)
+   -Dname (or -Dname=value)
+       pass the defined name(s) to TypEr
+       (The syntax of defines is the same as that used by \"erlc\".)
+   -I include_dir
+       pass the include_dir to TypEr
+       (The syntax of includes is the same as that used by \"erlc\".)
+   -pa dir
+   -pz dir
+       Set code path options to TypEr
+       (This is useful for files that use parse tranforms.)
+   --version (or -v)
+       prints the Typer version and exits
+   --help (or -h)
+       prints this message and exits
+
+ Note:
+   * denotes that multiple occurrences of these options are possible.
+">>,
+  io:put_chars(S),
+  erlang:halt(0).
+
+%%--------------------------------------------------------------------
+%% Handle messages.                         
+%%-------------------------------------------------------------------- 
+
+rcv_ext_types() ->
+  Self = self(),
+  Self ! {Self, done},
+  rcv_ext_types(Self, []).
+
+rcv_ext_types(Self, ExtTypes) ->
+  receive
+    {Self, ext_types, ExtType} ->
+      rcv_ext_types(Self, [ExtType|ExtTypes]);
+    {Self, done} ->
+      lists:usort(ExtTypes)
+  end.
+
+%%--------------------------------------------------------------------
+%% A convenient abstraction of a Key-Value mapping data structure
+%% specialized for the uses in this module
+%%--------------------------------------------------------------------
+
+-type map_dict() :: dict:dict().
+
+-spec map__new() -> map_dict().
+map__new() ->
+  dict:new().
+
+-spec map__insert({term(), term()}, map_dict()) -> map_dict().
+map__insert(Object, Map) ->
+  {Key, Value} = Object,
+  dict:store(Key, Value, Map).
+
+-spec map__lookup(term(), map_dict()) -> term().
+map__lookup(Key, Map) ->
+  try dict:fetch(Key, Map) catch error:_ -> none end.
+
+-spec map__from_list([{fa(), term()}]) -> map_dict().
+map__from_list(List) ->
+  dict:from_list(List).
+
+-spec map__remove(term(), map_dict()) -> map_dict().
+map__remove(Key, Dict) ->
+  dict:erase(Key, Dict).
+
+-spec map__fold(fun((term(), term(), term()) -> map_dict()), map_dict(), map_dict()) -> map_dict().
+map__fold(Fun, Acc0, Dict) -> 
+  dict:fold(Fun, Acc0, Dict).