See discussion of
whether links should be typed .
Descriptive (normal) link types are mainly for the benefit of
users and tracing, and graphics representation algorithms.
Some link types for example express relationships between the
things described by two nodes.
A Is part of B / B includes A
A Made B / B is made by A
A Uses B / B is used by A
A refers to B / B is referred to by A
Magic link types
These have a significance known to the system, and may be
treated in special ways. Many of these relate whole nodes,
rather than particular anchors within them. (See also multiended links and predicate
The destination is the related index for a search by a
user reading this document who asks for an index search
A document may have any number of index links, causing
several indexes top be searched in a client-defined manner.
The destination of the link is an index which should be
used to resiolve glossary queries in the document. (Typically,
a double-clik on a word which is not within an anchor).
A document may have any number of glossary links.
The information in the destination node is additional to
that in the source node, and may be viewed at the same time. It
may be filtered out (as a function of author?).
Annotation is used by one person to write the equivalent of
"margin notes" or other criticism on another's document, for
Tracing may ignore
annotations when generating trees or sequences.
Next, Previous, Up
These terms may be applied to the tree the user creates in
her browsing, but if the author puts links in, then a tree
structure may be proposed by the author. This is very natural
with hypertext versiins of books, etc.
If this link is followed, the node at the end of it is
embedded into the display of the source node. This is supported
by Guide, but not many other systems. It is used, in effect, by
those systems (VAX/notes under Decwindows, Microsoft Word)
which allow "Outlining" -- expanding a tree bit by bit.
The browser has a more difficult job to do if this is
person described by node A is author of node B
This information can be used for protection, and informing
authors of interest, for sending mail to authors, etc.
person described by node A is interested in node B
This information can be used for informing readers of
Node A is in fact a set of differences between B and its
version. This information will probably not be stored as
nodes, but be generated from regular diff files. or some other