Add alias for const_iterator

Older generic code (e.g. before auto) might require
const_iterator, so provide it as an alias to iterator.

lib/coveo/enumerable/enumerable.h

@@ -42,6 +42,10 @@ class enumerable
  // Forward declaration of iterator class.
  class iterator;
 
+ // Even though begin() and end() are already const, some might want
+ // to use const_iterator, to let's create an alias.
+ typedef iterator const_iterator;
+
 private:
  next_delegate zero_; // Next delegate which we will clone to iterate sequence.
  size_delegate size_; // Optional size delegate.
@@ -105,9 +109,16 @@ class enumerable
  iterator begin() const {
  return iterator(*this, false);
  }
+ iterator cbegin() const {
+ return begin();
+ }
+
  iterator end() const {
  return iterator(*this, true);
  }
+ iterator cend() const {
+ return end();
+ }
 
  // Access to size of sequence
  bool has_fast_size() const {

tests/coveo/enumerable/enumerable_tests.cpp

@@ -23,6 +23,12 @@ void validate_sequence(const coveo::enumerable<T>& seq, const C& expected, bool
  COVEO_ASSERT(obj == *eit++);
  }
  COVEO_ASSERT(eit == eend);
+ eit = std::begin(expected);
+ for (auto sit = seq.cbegin(), send = seq.cend(); sit != send; ++sit) {
+ COVEO_ASSERT(eit != eend);
+ COVEO_ASSERT(*sit == *eit++);
+ }
+ COVEO_ASSERT(eit == eend);
  COVEO_ASSERT(seq.has_fast_size() == fast_size);
  COVEO_ASSERT(seq.size() == expected.size());
 }