!ASIS Issue #043
!topic  Move type declarations to apropriate child packages
!reference  ASIS 95
!from  Doug Smith 97-02-24
!keywords  encapsulation type declaration child package
!discussion

Many type declarations in the ASIS package should be moved to the
child packages.

 The appropriate packaging of types with their associated operations
 is lost by collecting all of the types in the ASIS package. For example,
 the type Asis.Traverse_Control should be declared in Asis.Iterator; or
 the subtype, Context_Clause_List (itself possibly unnecessary) should
 be moved to Asis.Elements.

 Evaluate each type declaration and determine the most appropriate
 encapsulation.

!resolution  Rejected.
!date 97-03-26
!Notes

This is an excellent comment and for the most part, ASIS conforms
to the principles of the concept.  For example, error types are in
Asis.Errors, container types are in Asis.Asis_Environments.Containers,
type Time is in Asis.Compilation_Units.Times, type Relationship is in
Asis.Compilations_Units.Relations, types relating to lines are in
Asis.Text, type Id is in package Asis.Ids, and types associated with
data decomposition are in Asis.Data_Decomposition.

There are fifteen types provided in package Asis.  Most of these types
are there because they were used by more than one ASIS package.  There
are basically three exceptions: Element kinds (of which
Context_Clause_List is a subtype), Unit kinds, and Traverse_Control.
Historically, Element kinds were separated in a package Element_Kinds
and Unit kinds were separated in a package Unit_Kinds.

When the ASIS packages were restructured under one parent package,
Asis (see Issue #016), the concensus was to include the Element kinds
and Unit kinds in the parent package Asis to highlight their
importance for the ASIS interface.

All these type declarations are now in one package, mainly for style
and ease of reading, etc.  Thus, the names of the types are at the top
level of ASIS and are prefixed with "Asis.".

Asis.Traverse_Control was originally in package Asis.Iterator; it was
moved to package Asis to support the generation of IDL.

See also Editorial Comment 013.