Flow: Print types closer to values they are used in.

Author: pvolok

jscomp/flow.ml

@@ -9,8 +9,7 @@ type state = {
  mutable type_ids: id SMap.t;
  mutable val_ids: id SMap.t;
 
- mutable types: decl list;
- mutable exports: decl list;
+ mutable decls: decl list;
 
  mutable curr_tvars: int list option;
 }
@@ -48,7 +47,7 @@ and p_sig s = function
  | Types.Sig_value (id, val_desc) ->
  let decl_name = get_val_id s (Ident.name id) in
  let decl_type = p_type_expr s val_desc.val_type in
- s.exports <- {decl_name; decl_type; decl_tvars = []} :: s.exports
+ s.decls <- Decl_val {decl_name; decl_type} :: s.decls
  | Sig_type _ -> () (* Types are declared on demand *)
  | Sig_typext _ -> ()
  | Sig_module _ -> () (* Non-toplevel values are not exposed *)
@@ -98,10 +97,10 @@ and p_type_expr s type_expr =
  let decl_name = get_type_id s type_name in
  let type_decl = Env.find_type path s.env in
  let decl_type = p_type_decl s type_decl in
- let decl_tvars = List.map (fun t -> t.Types.id) type_decl.Types.type_params in
+ let tvars = List.map (fun t -> t.Types.id) type_decl.Types.type_params in
  s.curr_tvars <- prev_tvars;
- let decl = {decl_name; decl_type; decl_tvars} in
- s.types <- decl :: s.types
+ let decl = Decl_type (tvars, {decl_name; decl_type}) in
+ s.decls <- decl :: s.decls
  end;
  p_type_name ~tl:(List.map (p_type_expr s) tl) s type_name
  end
@@ -179,14 +178,12 @@ let print_signature env sigs =
  used_types = [];
  type_ids = SMap.empty;
  val_ids = SMap.empty;
- types = [];
- exports = [];
+ decls = [];
  curr_tvars = None;
  } in
  List.iter (p_sig s) sigs;
  rename_types s;
  let prog = {
- prog_types = List.rev s.types;
- prog_exports = List.rev s.exports;
+ prog_decls = List.rev s.decls;
  } in
  Flow_print.print prog

jscomp/flow_print.ml

@@ -37,20 +37,18 @@ let rec print_type = function
  let types_str = types |> List.map print_type |> String.concat ", " in
  "[" ^ types_str ^ "]"
 
-let print_type_decl decl =
- let tvars = print_tvars decl.decl_tvars in
- let type_str = print_type decl.decl_type in
- "type " ^ decl.decl_name.id ^ tvars ^ " = " ^ type_str
-
 let print_decl decl =
- let type_ = print_type decl.decl_type in
- "declare export var " ^ decl.decl_name.id ^ ": " ^ type_ ^ ";"
+ match decl with
+ | Decl_type (tvars, desc) ->
+ let tvars = print_tvars tvars in
+ let type_str = print_type desc.decl_type in
+ "type " ^ desc.decl_name.id ^ tvars ^ " = " ^ type_str
+ | Decl_val desc ->
+ let type_ = print_type desc.decl_type in
+ "declare export var " ^ desc.decl_name.id ^ ": " ^ type_ ^ ";"
 
 let print prog =
- let types = List.map print_type_decl prog.prog_types in
- let decls = List.map print_decl prog.prog_exports in
+ let decls = List.map print_decl prog.prog_decls in
  "// @flow\n\n" ^
- (String.concat "\n\n" types) ^
- "\n\n" ^
  (String.concat "\n\n" decls) ^
  "\n"

jscomp/flow_tree.ml

@@ -1,12 +1,14 @@
 type prog = {
- prog_types: decl list;
- prog_exports: decl list;
+ prog_decls: decl list;
 }
 
-and decl = {
+and decl =
+ | Decl_type of (* tvars *) int list * decl_desc
+ | Decl_val of decl_desc
+
+and decl_desc = {
  decl_name: id;
  decl_type: type_;
- decl_tvars: int list;
 }
 
 and type_ =

jscomp/test_flow/main.js.flow

@@ -1,35 +1,35 @@
 // @flow
 
-type Mod__t = number
-
-type rec_t = /* Type_record */any
-
-type obj_t = /* Tobject */any
-
-type Util__t = {id: number}
-
-type tt$0 = number
-
-type pair$0<TVAR_2148> = [TVAR_2148, TVAR_2148]
-
 declare export var tuple: [string, number, number, 0 | 1, 0 | 1];
 
+type Mod__t = number
+
 declare export var aliased: Mod__t;
 
 declare export var js_obj: {id: number, name: string};
 
+type rec_t = /* Type_record */any
+
 declare export var record: rec_t;
 
+type obj_t = /* Tobject */any
+
 declare export var obj_arg: (p0: obj_t) => void;
 
 declare export var arr: Array<number>;
 
+type Util__t = {id: number}
+
 declare export var from_util: (p0: Util__t) => void;
 
+type tt$0 = number
+
 declare export var tt: tt$0;
 
 declare export var iter: <TVAR_2135>(p0: Array<TVAR_2135>, p1: (p0: TVAR_2135) => void) => void;
 
+type pair$0<TVAR_2148> = [TVAR_2148, TVAR_2148]
+
 declare export var pair: <TVAR_2176>(p0: pair$0<TVAR_2176>) => void;
 
 declare export var tuple_with_fn: [<TVAR_2197>(p0: pair$0<TVAR_2197>) => void, number];

jscomp/test_flow/util.js.flow

@@ -1,5 +1,3 @@
 // @flow
 
-
-
 declare export var next: (p0: void) => number;