Merge branch 'ta/nested-records' into dev

* ta/nested-records:
  Document R14 paren-less record access/update
  Support nested record field access without parentheses

OTP-8597 ta/nested-records

Nested records can now be accessed without parenthesis. See the Reference
Manual for examples. (Thanks to YAMASHINA Hio and Tuncer Ayaz.)

3 files changed, 62 insertions, 10 deletions

diff --git a/lib/compiler/test/record_SUITE.erl b/lib/compiler/test/record_SUITE.erl
index bd2ffd7f65..f26ff769c7 100644
--- a/lib/compiler/test/record_SUITE.erl
+++ b/lib/compiler/test/record_SUITE.erl
@@ -1,19 +1,19 @@
 %%
 %% %CopyrightBegin%
-%% 
-%% Copyright Ericsson AB 2003-2009. All Rights Reserved.
-%% 
+%%
+%% Copyright Ericsson AB 2003-2010. All Rights Reserved.
+%%
 %% The contents of this file are subject to the Erlang Public License,
 %% Version 1.1, (the "License"); you may not use this file except in
 %% compliance with the License. You should have received a copy of the
 %% Erlang Public License along with this software. If not, it can be
 %% retrieved online at http://www.erlang.org/.
-%% 
+%%
 %% Software distributed under the License is distributed on an "AS IS"
 %% basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See
 %% the License for the specific language governing rights and limitations
 %% under the License.
-%% 
+%%
 %% %CopyrightEnd%
 %%
 %%% Purpose : Test records.
@@ -24,7 +24,7 @@
 
 -export([all/1,init_per_testcase/2,fin_per_testcase/2,
 	 errors/1,record_test_2/1,record_test_3/1,record_access_in_guards/1,
-	 guard_opt/1,eval_once/1,foobar/1,missing_test_heap/1]).
+	 guard_opt/1,eval_once/1,foobar/1,missing_test_heap/1, nested_access/1]).
 
 init_per_testcase(_Case, Config) ->
     ?line Dog = test_server:timetrap(test_server:minutes(2)),
@@ -38,7 +38,7 @@ fin_per_testcase(_Case, Config) ->
 all(suite) ->
     test_lib:recompile(?MODULE),
     [errors,record_test_2,record_test_3,record_access_in_guards,
-     guard_opt,eval_once,foobar,missing_test_heap].
+     guard_opt,eval_once,foobar,missing_test_heap,nested_access].
 
 -record(foo, {a,b,c,d}).
 -record(bar, {a,b,c,d}).
@@ -522,4 +522,29 @@ missing_test_heap_1(A = #foo_rec {foo_1 = _B,
   	       foo_3 = C + 1,
   	       foo_2 = D + 1}.
 
+-record(nrec0, {name = <<"nested0">>}).
+-record(nrec1, {name = <<"nested1">>, nrec0=#nrec0{}}).
+-record(nrec2, {name = <<"nested2">>, nrec1=#nrec1{}}).
+
+nested_access(Config) when is_list(Config) ->
+    N0 = #nrec0{},
+    N1 = #nrec1{},
+    N2 = #nrec2{},
+    ?line <<"nested0">> = N0#nrec0.name,
+    ?line <<"nested1">> = N1#nrec1.name,
+    ?line <<"nested2">> = N2#nrec2.name,
+    ?line <<"nested0">> = N1#nrec1.nrec0#nrec0.name,
+    ?line <<"nested0">> = N2#nrec2.nrec1#nrec1.nrec0#nrec0.name,
+    ?line <<"nested1">> = N2#nrec2.nrec1#nrec1.name,
+    ?line <<"nested0">> = ((N2#nrec2.nrec1)#nrec1.nrec0)#nrec0.name,
+
+    N1a = N2#nrec2.nrec1#nrec1{name = <<"nested1a">>},
+    ?line <<"nested1a">> = N1a#nrec1.name,
+
+    N2a = N2#nrec2.nrec1#nrec1.nrec0#nrec0{name = <<"nested0a">>},
+    N2b = ((N2#nrec2.nrec1)#nrec1.nrec0)#nrec0{name = <<"nested0a">>},
+    ?line <<"nested0a">> = N2a#nrec0.name,
+    ?line N2a = N2b,
+    ok.
+
 id(I) -> I.
diff --git a/lib/stdlib/src/erl_parse.yrl b/lib/stdlib/src/erl_parse.yrl
index 7145cf13fd..69807aad83 100644
--- a/lib/stdlib/src/erl_parse.yrl
+++ b/lib/stdlib/src/erl_parse.yrl
@@ -335,6 +335,10 @@ record_expr -> expr_max '#' atom '.' atom :
 	{record_field,?line('$2'),'$1',element(3, '$3'),'$5'}.
 record_expr -> expr_max '#' atom record_tuple :
 	{record,?line('$2'),'$1',element(3, '$3'),'$4'}.
+record_expr -> record_expr '#' atom '.' atom :
+	{record_field,?line('$2'),'$1',element(3, '$3'),'$5'}.
+record_expr -> record_expr '#' atom record_tuple :
+	{record,?line('$2'),'$1',element(3, '$3'),'$4'}.
 
 record_tuple -> '{' '}' : [].
 record_tuple -> '{' record_fields '}' : '$2'.
diff --git a/system/doc/reference_manual/records.xml b/system/doc/reference_manual/records.xml
index e2fe5fe8de..d01d883ef3 100644
--- a/system/doc/reference_manual/records.xml
+++ b/system/doc/reference_manual/records.xml
@@ -4,7 +4,7 @@
 <chapter>
   <header>
     <copyright>
-      <year>2003</year><year>2009</year>
+      <year>2003</year><year>2010</year>
       <holder>Ericsson AB. All Rights Reserved.</holder>
     </copyright>
     <legalnotice>
@@ -13,12 +13,12 @@
       compliance with the License. You should have received a copy of the
       Erlang Public License along with this software. If not, it can be
       retrieved online at http://www.erlang.org/.
-    
+
       Software distributed under the License is distributed on an "AS IS"
       basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See
       the License for the specific language governing rights and limitations
       under the License.
-    
+
     </legalnotice>
 
     <title>Records</title>
@@ -145,6 +145,29 @@ is_person(_P) ->
   </section>
 
   <section>
+    <title>Nested records</title>
+    <p>Beginning with R14 parentheses when accessing or updating nested
+      records can be omitted. Assuming we have the following record
+      definitions:</p>
+    <pre>
+-record(nrec0, {name = "nested0"}).
+-record(nrec1, {name = "nested1", nrec0=#nrec0{}}).
+-record(nrec2, {name = "nested2", nrec1=#nrec1{}}).
+
+N2 = #nrec2{},
+    </pre>
+    <p>Before R14 you would have needed to use parentheses as following:</p>
+    <pre>
+"nested0" = ((N2#nrec2.nrec1)#nrec1.nrec0)#nrec0.name,
+N0n = ((N2#nrec2.nrec1)#nrec1.nrec0)#nrec0{name = "nested0a"},
+    </pre>
+    <p>Since R14 you can also write:</p>
+    <pre>
+"nested0" = N2#nrec2.nrec1#nrec1.nrec0#nrec0.name,
+N0n = N2#nrec2.nrec1#nrec1.nrec0#nrec0{name = "nested0a"},</pre>
+  </section>
+
+  <section>
     <title>Internal Representation of Records</title>
     <p>Record expressions are translated to tuple expressions during
       compilation. A record defined as</p>