Functions

Expression	Return type	Returns	Complexity
`begin(x)`	`range_iterator<X>::type`	`p.first` if `p` is of type `std::pair<T>` `a` if `a` is an array `range_begin(x)` if that expression would invoke a function found by ADL `t.begin()` otherwise	constant time
`end(x)`	`range_iterator<X>::type`	`p.second` if `p` is of type `std::pair<T>` `a + sz` if `a` is an array of size `sz` `range_end(x)` if that expression would invoke a function found by ADL `t.end()` otherwise	constant time
`empty(x)`	`bool`	`boost::begin(x) == boost::end(x)`	constant time
`distance(x)`	`range_difference<X>::type`	`std::distance(boost::begin(x),boost::end(x))`	-
`size(x)`	`range_size<X>::type`	`range_calculate_size(x)` which by default is `boost::end(x) - boost::begin(x)`. Users may supply alternative implementations by implementing `range_calculate_size(x)` so that it will be found via ADL	constant time
`rbegin(x)`	`range_reverse_iterator<X>::type`	`range_reverse_iterator<X>::type(boost::end(x))`	constant time
`rend(x)`	`range_reverse_iterator<X>::type`	`range_reverse_iterator<X>::type(boost::begin(x))`	constant time
`const_begin(x)`	`range_iterator<const X>::type`	`range_iterator<const X>::type(boost::begin(x))`	constant time
`const_end(x)`	`range_iterator<const X>::type`	`range_iterator<const X>::type(boost::end(x))`	constant time
`const_rbegin(x)`	`range_reverse_iterator<const X>::type`	`range_reverse_iterator<const X>::type(boost::rbegin(x))`	constant time
`const_rend(x)`	`range_reverse_iterator<const X>::type`	`range_reverse_iterator<const X>::type(boost::rend(x))`	constant time
`as_literal(x)`	`iterator_range<U>` where `U` is `Char*` if `x` is a pointer to a string and `U` is `range_iterator<X>::type` otherwise	`[s,s + std::char_traits<X>::length(s))` if `s` is a `Char*` or an array of `Char` `[boost::begin(x),boost::end(x))` otherwise	linear time for pointers to a string or arrays of `Char`, constant time otherwise
`as_array(x)`	`iterator_range<X>`	`[boost::begin(x),boost::end(x))`

The special const_-named functions are useful when you want to document clearly that your code is read-only.

as_literal() can be used internally in string algorithm libraries such that arrays of characters are handled correctly.

as_array() can be used with string algorithm libraries to make it clear that arrays of characters are handled like an array and not like a string.

Notice that the above functions should always be called with qualification (boost::) to prevent unintended Argument Dependent Lookup (ADL).