From ca1c1f8d1a4fe4f7b19b9959c48bd64915215f24 Mon Sep 17 00:00:00 2001
From: Hans Bolinder <hasse@erlang.org>
Date: Wed, 20 May 2015 12:45:37 +0200
Subject: stdlib: Introduce precedence for operators in types

Add new functions erl_parse:type_inop_prec() and
erl_parse:type_preop_prec().

Get rid of paren_type used for parentheses in types.
---
 lib/stdlib/src/erl_parse.yrl | 64 ++++++++++++++++++++++++++++----------------
 1 file changed, 41 insertions(+), 23 deletions(-)

(limited to 'lib/stdlib/src/erl_parse.yrl')

diff --git a/lib/stdlib/src/erl_parse.yrl b/lib/stdlib/src/erl_parse.yrl
index e328e065e3..274bb2a782 100644
--- a/lib/stdlib/src/erl_parse.yrl
+++ b/lib/stdlib/src/erl_parse.yrl
@@ -125,22 +125,19 @@ top_type_100 -> type_200                  : '$1'.
 top_type_100 -> type_200 '|' top_type_100 : lift_unions('$1','$3').
 
 type_200 -> type_300 '..' type_300        : {type, ?anno('$1'), range,
-                                             [skip_paren('$1'),
-                                              skip_paren('$3')]}.
+                                             ['$1', '$3']}.
 type_200 -> type_300                      : '$1'.
 
-type_300 -> type_300 add_op type_400      : ?mkop2(skip_paren('$1'),
-                                                   '$2', skip_paren('$3')).
+type_300 -> type_300 add_op type_400      : ?mkop2('$1', '$2', '$3').
 type_300 -> type_400                      : '$1'.
 
-type_400 -> type_400 mult_op type_500     : ?mkop2(skip_paren('$1'),
-                                                   '$2', skip_paren('$3')).
+type_400 -> type_400 mult_op type_500     : ?mkop2('$1', '$2', '$3').
 type_400 -> type_500                      : '$1'.
 
-type_500 -> prefix_op type                : ?mkop1('$1', skip_paren('$2')).
+type_500 -> prefix_op type                : ?mkop1('$1', '$2').
 type_500 -> type                          : '$1'.
 
-type -> '(' top_type ')'                  : {paren_type, ?anno('$2'), ['$2']}.
+type -> '(' top_type ')'                  : '$2'.
 type -> var                               : '$1'.
 type -> atom                              : '$1'.
 type -> atom '(' ')'                      : build_gen_type('$1').
@@ -524,6 +521,7 @@ Erlang code.
 -export([normalise/1,abstract/1,tokens/1,tokens/2]).
 -export([abstract/2]).
 -export([inop_prec/1,preop_prec/1,func_prec/0,max_prec/0]).
+-export([type_inop_prec/1,type_preop_prec/1]).
 -export([map_anno/2, fold_anno/3, mapfold_anno/3,
          new_anno/1, anno_to_term/1, anno_from_term/1]).
 -export([set_line/2,get_attribute/2,get_attributes/1]).
@@ -671,11 +669,6 @@ lift_unions(T1, {type, _Aa, union, List}) ->
 lift_unions(T1, T2) ->
     {type, ?anno(T1), union, [T1, T2]}.
 
-skip_paren({paren_type,_A,[Type]}) ->
-    skip_paren(Type);
-skip_paren(Type) ->
-    Type.
-
 build_gen_type({atom, Aa, tuple}) ->
     {type, Aa, tuple, any};
 build_gen_type({atom, Aa, map}) ->
@@ -687,7 +680,7 @@ build_gen_type({atom, Aa, Name}) ->
 build_bin_type([{var, _, '_'}|Left], Int) ->
     build_bin_type(Left, Int);
 build_bin_type([], Int) ->
-    skip_paren(Int);
+    Int;
 build_bin_type([{var, Aa, _}|_], _) ->
     ret_err(Aa, "Bad binary type").
 
@@ -807,8 +800,7 @@ record_fields([{typed,Expr,TypeInfo}|Fields]) ->
 	    {atom, Aa, _} ->
                 case has_undefined(TypeInfo) of
                     false ->
-                        TypeInfo2 = maybe_add_paren(TypeInfo),
-                        lift_unions(abstract2(undefined, Aa), TypeInfo2);
+                        lift_unions(abstract2(undefined, Aa), TypeInfo);
                     true ->
                         TypeInfo
                 end
@@ -822,18 +814,11 @@ has_undefined({atom,_,undefined}) ->
     true;
 has_undefined({ann_type,_,[_,T]}) ->
     has_undefined(T);
-has_undefined({paren_type,_,[T]}) ->
-    has_undefined(T);
 has_undefined({type,_,union,Ts}) ->
     lists:any(fun has_undefined/1, Ts);
 has_undefined(_) ->
     false.
 
-maybe_add_paren({ann_type,A,T}) ->
-    {paren_type,A,[{ann_type,A,T}]};
-maybe_add_paren(T) ->
-    T.
-
 term(Expr) ->
     try normalise(Expr)
     catch _:_R -> ret_err(?anno(Expr), "bad attribute")
@@ -1099,6 +1084,39 @@ func_prec() -> {800,700}.
 
 max_prec() -> 900.
 
+-type prec() :: non_neg_integer().
+
+-type type_inop() :: '::' | '|' | '..' | '+' | '-' | 'bor' | 'bxor'
+                   | 'bsl' | 'bsr' | '*' | '/' | 'div' | 'rem' | 'band'.
+
+-type type_preop() :: '+' | '-' | 'bnot' | '#'.
+
+-spec type_inop_prec(type_inop()) -> {prec(), prec(), prec()}.
+
+type_inop_prec('=') -> {150,100,100};
+type_inop_prec('::') -> {160,150,150};
+type_inop_prec('|') -> {180,170,170};
+type_inop_prec('..') -> {300,200,300};
+type_inop_prec('+') -> {400,400,500};
+type_inop_prec('-') -> {400,400,500};
+type_inop_prec('bor') -> {400,400,500};
+type_inop_prec('bxor') -> {400,400,500};
+type_inop_prec('bsl') -> {400,400,500};
+type_inop_prec('bsr') -> {400,400,500};
+type_inop_prec('*') -> {500,500,600};
+type_inop_prec('/') -> {500,500,600};
+type_inop_prec('div') -> {500,500,600};
+type_inop_prec('rem') -> {500,500,600};
+type_inop_prec('band') -> {500,500,600};
+type_inop_prec('#') -> {800,700,800}.
+
+-spec type_preop_prec(type_preop()) -> {prec(), prec()}.
+
+type_preop_prec('+') -> {600,700};
+type_preop_prec('-') -> {600,700};
+type_preop_prec('bnot') -> {600,700};
+type_preop_prec('#') -> {700,800}.
+
 %%% [Experimental]. The parser just copies the attributes of the
 %%% scanner tokens to the abstract format. This design decision has
 %%% been hidden to some extent: use set_line() and get_attribute() to
-- 
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