recommend range-based for. Bump version to 0.5.

rules.org

-#+MACRO: version 0.4
-#+LaTeX_HEADER: \def\rulesversion{0.4}
+#+MACRO: version 0.5
+#+LaTeX_HEADER: \def\rulesversion{0.5}
 #+TITLE: ATLAS C++ coding guidelines, version {{{version}}}
 #+AUTHOR: Shaun Roe (CERN), Scott Snyder (BNL), and the former ATLAS Quality Control group
 #+EMAIL: Correspondence to snyder@bnl.gov.
@@ -433,6 +433,34 @@ vector<int> x;  // Missing std!
    change the loop variable within the loop body rather than inside the
    expression executed after each iteration.
 
+ - *Prefer range-based for loops.*  [<<prefer-range-based-for>>]
+
+   C++11 introduced the `range-based for'.  Prefer using this to a loop
+   with explicit iterators; that is, prefer:
+   #+BEGIN_EXAMPLE
+std::vector<int> v = ...;
+for (int x : v) {
+  doSomething (x);
+}
+#+END_EXAMPLE
+
+   to
+   #+BEGIN_EXAMPLE
+std::vector<int> v = ...;
+for (std::vector<int>::const_iterator it = v.begin();
+     it != v.end();
+   ++it)
+{
+  doSomething (*it);
+}
+#+END_EXAMPLE
+
+   In some cases you can't make this replacement; for example, if you
+   need to call methods on the iterator itself, or you need to manage
+   multiple iterators within the loop.  But most simple loops over
+   STL ranges are most simply written with a range-based for.
+
+
  - *All switch statements must have a default clause.*  [<<switch-default>>]
 
    In some cases the default clause can never be reached because there
@@ -2848,6 +2876,7 @@ The comment includes the fact that it is the perpendicular distance.
 
 ** Version 0.5
  - Add an initial set of guidelines for AthenaMT.
+ - Add recommendation to prefer range-based for.
 
 ** Version 0.4
  - Minor updates: we're now using c++14.  Add note about implicit fallthrough