1) Namespaces

Namespaces : Context

We need to create name spaces.

Namespaces are

a labeled/named subset of identified/labeled content,
- content can then be precisely identified with a compound identfier
- the conjuction of the subset name and the content name.
commonly structured as nested hierarchies to allow reuse of names in different contexts.
typically employed for the purpose of grouping symbols and identifiers around a particular functionality
- to avoid name collisions between multiple identifiers that share the same name.
hierarchical, ie sets of namespaces can be nested within another namespace

Namespaces : Examples

In TDX

NAMESPACE $project

Puts anything following in the current project context

NAMESPACE $project:subComponent
OR
NAMESPACE subComponent

Puts everyting that follows into the project's subComponent namespace

NAMESPACE subComponent - $system:language
OR
NAMESPACE subComponent - language
OR
NAMESPACE subComponent - $dxlib:codelib

Puts everything that follows into the project's subComponent namespace AND incorporates the system defined "language" namespace contents accessible to the project.

NB.

The default namespace is $project and coresponds to the base directory of the current project.
The default namespace to be included is $system and coresponds to a file refererd to by the dxiner environment variable.
If any other $name is used, it coresponds to a system based environment variable containing a directory where the coresponding ".tdx" file can be found. The variable can consist of a selection of paths, separated by semi-colons.

In VDX

Namespaces : Semantics

Namespaces : Data Definition

To store namespaces we need a structure similar to that detailed below ... explaination of the notation

In TDX

NAMESPACE $project:tdx - $system:lang 
  // however $project is implied and not really needed

  SINGLETON design
    namespace ourNameSpaces = NEW namespace("system")

    SYNTAX
      textualDesignClause := ( designClause )+;
      designClause := namespaceClause ( designComponentClause )+;
      designComponentClause := ... ;

  CLASS namespace(ubyte$ name)
    namespace{} subSpaces
    
    namespace(namespace) addNamespace(newNameSpace) =
    {
      subSpaces->add(newNameSpace)
      RETURN newNameSpace
    }

    SYNTAX
        namespaceClause := "NAMESPACE" newNameSpaceClause 
          ( "-" ( existingNameClause )+ );
        newNameSpaceClause := ( "$" ident ( ":" ident )* | ident ( ":" ident )+ );
        existingNameClause := ( "$" ident ( ":" ident )* | ident ( ":" ident )+ );