# Advanced constructs

We have now covered most of Algol 68. All that remains is the identity relation, the parallel clause, the mode `BITS`, completers, different precisions of numbers and means of accessing operating system facilities. Most of these are deceptively simple. The identity relation is used with modes containing multiple `REF`s which take up the greater part of this chapter. The `BITS` mode and the parallel clause are introduced in later sections. Different numerical precisions and access to operating system facilities is mainly covered in chapter 12. We start with access to the machine word.

Subsections

- Bits, bytes and words
  - Radix arithmetic
  - Exercises
- The mode `BITS`
  - Monadic operators for `BITS`
  - Dyadic operators for `BITS`
  - Exercises
- Overlapping slices
  - Exercises
- Completers
- References to names
  - Exercises
- Identity relations
  - Exercises
- The value `NIL`
  - Exercises
- Queues
  - Exercises
- The procedure `add fan`
  - Exercises
- More queue procedures
  - Exercises
- Trees
  - Exercises
- Parallel programming
- Summary