Welcome to Programming in Ada 2012 which has been triggered by the recent ISO standardization of Ada 2012.

The original language, devised in the 1980s, is known as Ada 83 and was followed by Ada 95, Ada 2005, and now Ada 2012. Ada has gained a reputation as being the language of choice when software needs to be correct. And as software pervades into more areas of society so that ever more software is safety critical or security critical, it is clear that the future for Ada is bright. One observes, for example, the growth in use of SPARK, the Ada based high integrity language widely used in areas such as avionics and signalling.

Ada 83 was a relatively simple but highly reliable language with emphasis on abstraction and information hiding. It was also notable for being perhaps the first practical language to include multitasking within the language itself.

Ada 95 added extra flexibility to the strongly typed and secure foundation provided by the Software Engineering approach of Ada 83. In particular it added the full dynamic features of Object Oriented Programming (OOP) and in fact was the first such language to become an ISO standard. Ada 95 also made important structural enhancements to visibility control by the addition of child units, it greatly improved multitasking by the addition of protected types, and added important basic material to the standard library.

Ada 2005 then made improvements in two key areas. It added more flexibility in the OOP area by the addition of multiple inheritance via interfaces and it added more facilities in the real-time area concerning scheduling algorithms, timing and other matters of great importance for embedded systems. It also added further facilities to the standard library such as the ability to manipulate containers.

Ada 2012 makes further important enhancements. These include features for contracts such as pre- and postconditions, tasking facilities to recognize multicore architectures, and major additions and improvements to the container library.

In more detail, the changes include

• • Contracts – pre- and postconditions, type invariants, and subtype predicates are perhaps the most dramatic new features. The introduction of these features prompted a rethink regarding the specification of various properties of entities in general. As a consequence the use of pragmas has largely been replaced by the elegant new syntax of aspect specifications which enables the properties to be given with the declaration of the entities concerned.