Retire two myths

3 files changed, 67 insertions, 28 deletions

diff --git a/system/doc/efficiency_guide/myths.xml b/system/doc/efficiency_guide/myths.xml
index 5d3ad78b23..7e2f3c8465 100644
--- a/system/doc/efficiency_guide/myths.xml
+++ b/system/doc/efficiency_guide/myths.xml
@@ -24,7 +24,7 @@
   The Initial Developer of the Original Code is Ericsson AB.
     </legalnotice>
 
-    <title>The Eight Myths of Erlang Performance</title>
+    <title>The Six Myths of Erlang Performance</title>
     <prepared>Bjorn Gustavsson</prepared>
     <docno></docno>
     <date>2007-11-10</date>
@@ -35,38 +35,13 @@
   <marker id="myths"></marker>
   <p>Some truths seem to live on well beyond their best-before date,
   perhaps because "information" spreads faster from person-to-person
-  than a single release note that says, for example, that funs
-  have become faster.</p>
+  than a single release note that says, for example, that body-recursive
+  calls have become faster.</p>
 
   <p>This section tries to kill the old truths (or semi-truths) that have
   become myths.</p>
 
   <section>
-    <title>Myth: Funs are Slow</title>
-    <p>Funs used to be very slow, slower than <c>apply/3</c>.
-    Originally, funs were implemented using nothing more than
-    compiler trickery, ordinary tuples, <c>apply/3</c>, and a great
-    deal of ingenuity.</p>
-
-    <p>But that is history. Funs was given its own data type
-    in R6B and was further optimized in R7B.
-    Now the cost for a fun call falls roughly between the cost for a call
-    to a local function and <c>apply/3</c>.</p>
-  </section>
-
-  <section>
-    <title>Myth: List Comprehensions are Slow</title>
-
-    <p>List comprehensions used to be implemented using funs, and in the
-    old days funs were indeed slow.</p>
-
-    <p>Nowadays, the compiler rewrites list comprehensions into an ordinary
-    recursive function. Using a tail-recursive function with
-    a reverse at the end would be still faster. Or would it?
-    That leads us to the next myth.</p>
-  </section>
-
-  <section>
     <title>Myth: Tail-Recursive Functions are Much Faster
     Than Recursive Functions</title>
 
diff --git a/system/doc/efficiency_guide/part.xml b/system/doc/efficiency_guide/part.xml
index 6e10a0c031..5673ddd320 100644
--- a/system/doc/efficiency_guide/part.xml
+++ b/system/doc/efficiency_guide/part.xml
@@ -39,5 +39,6 @@
   <xi:include href="drivers.xml"/>
   <xi:include href="advanced.xml"/>
   <xi:include href="profiling.xml"/>
+  <xi:include href="retired_myths.xml"/>
 </part>
 
diff --git a/system/doc/efficiency_guide/retired_myths.xml b/system/doc/efficiency_guide/retired_myths.xml
new file mode 100644
index 0000000000..37f46566cd
--- /dev/null
+++ b/system/doc/efficiency_guide/retired_myths.xml
@@ -0,0 +1,63 @@
+<?xml version="1.0" encoding="utf-8" ?>
+<!DOCTYPE chapter SYSTEM "chapter.dtd">
+
+<chapter>
+  <header>
+    <copyright>
+      <year>2016</year>
+      <year>2016</year>
+      <holder>Ericsson AB, All Rights Reserved</holder>
+    </copyright>
+    <legalnotice>
+  Licensed under the Apache License, Version 2.0 (the "License");
+  you may not use this file except in compliance with the License.
+  You may obtain a copy of the License at
+
+      http://www.apache.org/licenses/LICENSE-2.0
+
+  Unless required by applicable law or agreed to in writing, software
+  distributed under the License is distributed on an "AS IS" BASIS,
+  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+  See the License for the specific language governing permissions and
+  limitations under the License.
+
+  The Initial Developer of the Original Code is Ericsson AB.
+    </legalnotice>
+    <marker id="retired_myths"/>
+    <title>Retired Myths</title>
+    <prepared>Bjorn Gustavsson</prepared>
+    <docno></docno>
+    <date>2016-06-07</date>
+    <rev></rev>
+    <file>retired_myths.xml</file>
+  </header>
+
+  <p>We belive that the truth finally has caught with the following,
+  retired myths.</p>
+
+  <section>
+    <title>Myth: Funs are Slow</title>
+    <p>Funs used to be very slow, slower than <c>apply/3</c>.
+    Originally, funs were implemented using nothing more than
+    compiler trickery, ordinary tuples, <c>apply/3</c>, and a great
+    deal of ingenuity.</p>
+
+    <p>But that is history. Funs was given its own data type
+    in R6B and was further optimized in R7B.
+    Now the cost for a fun call falls roughly between the cost for a call
+    to a local function and <c>apply/3</c>.</p>
+  </section>
+
+  <section>
+    <title>Myth: List Comprehensions are Slow</title>
+
+    <p>List comprehensions used to be implemented using funs, and in the
+    old days funs were indeed slow.</p>
+
+    <p>Nowadays, the compiler rewrites list comprehensions into an ordinary
+    recursive function. Using a tail-recursive function with
+    a reverse at the end would be still faster. Or would it?
+    That leads us to the myth that tail-recursive functions are faster
+    than body-recursive functions.</p>
+  </section>
+</chapter>