Rationale for Ada 2012

John Barnes
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7.1 Overview of changes: Predefined library

The WG9 guidance document [1] does not specifically identify problems in this area other than through a general exhortation to remedy shortcomings.
We have already discussed the additional library packages in the area of tasking and real-time in Chapter 5). There are also many additional library packages concerning containers and these will be discussed in Chapter 8. The following Ada issues cover the relevant changes in other areas and are described in detail in this chapter:
Bounded containers and other container issues
Add a From parameter to Find_Token
Extend file name processing in Ada.Directories
Adding locale capabilities
String encoding package
Wide_Character and Wide_Wide_Character classification and folding
Questions on locales
Use latest version of ISO/IEC 10646
Stream_IO should be preelaborated
Defaulted environment variable queries
Internationalization of Ada 
These changes can be grouped as follows.
A number of enhancements concern strings and characters. These include comprehensive new packages to support conversions between strings (and wide strings and wide-wide strings) and the UTF-8 and UTF-16 encodings (137). It is important to note that Ada 2012 directly supports source code in UTF-8 (286). Additional facilities are also provided for the classification of characters and new packages added for similar operations on wide characters and wide wide characters (185, 266). A minor change is the provision of a further procedure Find_Token{ with an additional parameter giving the start of the search (31).
The file name processing in Ada.Directories is enhanced to overcome some shortcomings (49).
A new package is added to enable a program to identify the locale in which it is being used (127, 233).
There are a number of additional facilities regarding hashing and case insensitive comparisons. The hashing issues really relate to containers but are briefly mentioned here for completeness (1, 286).
Finally, other improvements are that the package Ada.Streams.Stream_IO is now preelaborated (283) and that an additional function Value is added to the package Ada.Environment_Variables (285).

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