Merge pull request #9223 from richcarl/apply-precedence

Make function application left associative so it can be chained

OTP-19866

Author: bjorng

lib/compiler/test/apply_SUITE.erl

@@ -23,9 +23,9 @@
 
 -export([all/0, suite/0,groups/0,init_per_suite/1, end_per_suite/1,
 	 init_per_group/2,end_per_group/2,
-         mfa/1,fun_apply/1,involved/1]).
+         mfa/1,fun_apply/1,precedence/1,involved/1]).
 
--export([foo/0,bar/1,baz/2]).
+-export([foo/0,bar/1,baz/2,get_callback/0]).
 
 -include_lib("common_test/include/ct.hrl").
 
@@ -38,6 +38,7 @@ groups() ->
     [{p,test_lib:parallel(),
       [mfa,
        fun_apply,
+       precedence,
        involved
       ]}].
 
@@ -139,6 +140,12 @@ fun_apply(Config) when is_list(Config) ->
 
     ok.
 
+get_callback() ->
+    lists.
+
+precedence(_Config) ->
+    [3,2,1] = ?MODULE:get_callback():reverse([1,2,3]).
+
 involved(_Config) ->
     self() ! message,
     ok = involved_1(),

lib/compiler/test/fun_SUITE.erl

@@ -26,7 +26,7 @@
 	 test1/1,overwritten_fun/1,otp_7202/1,bif_fun/1,
          external/1,eep37/1,badarity/1,badfun/1,
          duplicated_fun/1,unused_fun/1,parallel_scopes/1,
-         coverage/1,leaky_environment/1]).
+         coverage/1,leaky_environment/1,chain/1]).
 
 %% Internal exports.
 -export([call_me/1,dup1/0,dup2/0]).
@@ -40,7 +40,7 @@ all() ->
 
 groups() ->
     [{p,[parallel],
-      [test1,overwritten_fun,otp_7202,bif_fun,external,eep37,
+      [test1,overwritten_fun,otp_7202,bif_fun,external,eep37,chain,
        badarity,badfun,duplicated_fun,unused_fun,
        parallel_scopes,
        coverage,leaky_environment]}].
@@ -204,13 +204,16 @@ external(Config) when is_list(Config) ->
 
     42 = (fun erlang:abs/1)(-42),
     42 = (id(fun erlang:abs/1))(-42),
+    42 = id(fun erlang:abs/1)(-42),
     42 = apply(fun erlang:abs/1, [-42]),
     42 = apply(id(fun erlang:abs/1), [-42]),
     6 = (fun lists:sum/1)([1,2,3]),
     6 = (id(fun lists:sum/1))([1,2,3]),
+    6 = id(fun lists:sum/1)([1,2,3]),
 
     {'EXIT',{{badarity,_},_}} = (catch (fun lists:sum/1)(1, 2, 3)),
     {'EXIT',{{badarity,_},_}} = (catch (id(fun lists:sum/1))(1, 2, 3)),
+    {'EXIT',{{badarity,_},_}} = (catch id(fun lists:sum/1)(1, 2, 3)),
     {'EXIT',{{badarity,_},_}} = (catch apply(fun lists:sum/1, [1,2,3])),
 
     {'EXIT',{badarg,_}} = (catch bad_external_fun()),
@@ -225,6 +228,11 @@ bad_external_fun() ->
     fun V0:V0/V0,                               %Should fail.
     never_reached.
 
+chain(_Config) ->
+    F3 = fun (A, B, C) -> {ok, (A + B) * C} end,
+    F0 = fun (A) -> fun (B) -> fun (C) -> F3(A,B,C) end end end,
+    {ok, 42} = F0(-2)(9)(6).
+
 %% Named funs.
 eep37(_Config) ->
     eep37_basic(),
@@ -243,7 +251,9 @@ eep37_basic() ->
 
 eep37_dup() ->
     dup1 = (dup1())(),
+    dup1 = dup1()(),
     dup2 = (dup2())(),
+    dup2 = dup2()(),
     ok.
 
 dup1() ->

lib/stdlib/src/erl_parse.yrl

@@ -114,6 +114,7 @@ Left 400 add_op.
 Left 500 mult_op.
 Unary 600 prefix_op.
 Nonassoc 700 '#'.
+Left 750 '('.
 Nonassoc 800 ':'.
 Nonassoc 900 clause_body_exprs.
 
@@ -271,9 +272,9 @@ expr -> map_expr : '$1'.
 expr -> function_call : '$1'.
 expr -> record_expr : '$1'.
 expr -> expr_remote : '$1'.
+expr -> expr_max : '$1'.
 
-expr_remote -> expr_max ':' expr_max : {remote,?anno('$2'),'$1','$3'}.
-expr_remote -> expr_max : '$1'.
+expr_remote -> expr ':' expr : {remote,?anno('$2'),'$1','$3'}.
 
 expr_max -> var : '$1'.
 expr_max -> atomic : '$1'.
@@ -433,11 +434,8 @@ record_fields -> record_field ',' record_fields : ['$1' | '$3'].
 record_field -> var '=' expr : {record_field,?anno('$1'),'$1','$3'}.
 record_field -> atom '=' expr : {record_field,?anno('$1'),'$1','$3'}.
 
-%% N.B. This is called from expr.
-
-function_call -> expr_remote argument_list :
-	{call,first_anno('$1'),'$1',element(1, '$2')}.
-
+function_call -> expr argument_list :
+        {call,first_anno('$1'),'$1',element(1, '$2')}.
 
 if_expr -> 'if' if_clauses 'end' : {'if',?anno('$1'),'$2'}.
 
@@ -2037,7 +2035,8 @@ inop_prec('div') -> {500,500,600};
 inop_prec('rem') -> {500,500,600};
 inop_prec('band') -> {500,500,600};
 inop_prec('and') -> {500,500,600};
-inop_prec('#') -> {800,700,800};
+inop_prec('#') -> {750,700,750};
+inop_prec('(') -> {750,750,800};
 inop_prec(':') -> {900,800,900};
 inop_prec('.') -> {900,900,1000}.