The Nls Conceptual Model - HP 9000 User Manual

1
However, the features of Hewlett-Packard's NLS enable the application designer
or programmer to create applications for an end-user's needs regardless of
the local language.
NLS
addresses an application's internal functions (such
as sorting and character handling) and the user interface (which includes
displayed messages, user inputs, and currency formats). An internationalized
program is really many programs in one, in that it uses and is supported by
tools that separate language-dependent features from the main program logic.
The NLS Conceptual Model
The NLS concept is a simple one. NLS allows one discrete program to
"speak" in a variety of languages.
NLS
consists of an extensive set of tools
and routines. All of its components support an "extended multi-language
application" consisting of three parts:
• A Language-Independent Program- The program displays messages in the
user's native language by using language-dependent features that are not a
fixed part of the program. The program does this in either of two ways:
o it processes the language-dependent data in a codeset-sensitive way; we
could call this the traditional
NLS
approach. Or,
o the program uses the Worldwide Portability Interface (WPI) to process
the language-dependent data. WPI's wide character encoding enables the
program to deal with data in a way that is codeset non-sensitive.
• Message Catalogs - There are no hard-coded messages in the source code.
Instead messages to the user (such as prompts and error messages) are stored
in external message catalogs with a version for each supported language.
For instance, instead of the source code containing the statement printf
("display this string"), the program calls a routine that opens a specific
message catalog containing the language-specific equivalent.
• Language Tables- This component of NLS contains language-specific
information and conventions unique to a particular locale (such as collation
sequence definitions and monetary conventions). Programs consult a
specific language table at run time according to the setting of the user's
environmental variables.
1-2 Overview