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.)

1 files changed, 26 insertions, 3 deletions

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>