NAME

       md_src_plugins_type_README - README

       • infos = Information about type plugin is in keys below

       • infos/author = Markus Raab elektra@libelektra.org

       • infos/licence = BSD

       • infos/needs =

       • infos/provides = check

       • infos/placements = presetstorage

       • infos/description = Copies meta data to keys using typebing

       This plugin is a type checker plugin using the COBRA data types.

   Additional Information
       A common and successful type system happens to be CORBA with IDL. The system is
       outstanding because of the many mappings it provides to other programming languages.

       The type checker plugin supports all basic CORBA types: short, unsigned_short, long,
       unsigned_long, long_long, unsigned_long_long, float, double, char, boolean, any and octet.
       In Elektra octet is the same as char. When checking any it will always be successful,
       regardless of the content. Elektra also added other types. empty will only yield true if
       there is no value. string allows any non-empty sequence of octets.

       Sometimes the type should expresses that, for example, both an empty or another type is
       valid. In Elektra a space-separated list of types expresses that. If any of those types
       match, the whole type is valid. For example, the type string empty equals the type any.
       This facility builds a union of the sets of instances existing types specify.

       enum works with a list of choices. Any of these choices confirms to the type, others do
       not. For example, the type FSType accepts all file system names, for example, ext2, jfs or
       vfat.

       The CORBA type system goes far beyond these basic types. In IDL, it is also allowed to
       define classes, interfaces and generic containers. These user-defined types are however
       not useful on a single Key.

       To sum up, many basic types like int or char are convenient and CORBA ensures that they
       can be converted to the specific type of the programming language.

   Restrictions
       The CORBA type system also has its limits. The types string and enum, however, can be
       unsatisfactory. While string is too general and makes no limit on how the sequence of
       characters is structured, the enumeration is too finite. For example, it is not possible
       to say that a string is not allowed to have a specific symbol in it.