A chapter from Practical Hypermedia: An Introduction to HyTime, by W. Eliot Kimber
ISBN 0-13-309899-0
This appendix summarizes the changes made to the first edition of the HyTime standard by the publication of second edition of the HyTime standard, ISO/IEC 10744:1997 in August 1997. These changes are grouped into four categories: syntax changes, new facilities, new architectural forms, and new and changed data content notations.
all-act
all-act
attribute list
form is now the activity
attribute list form. The activity
attribute is replaced by the actrules
attribute, which points to the activity policy association rules (actrule
) that govern the element. See "6.7.3 Activity policy association ".all-id
all-id
attribute list has been
redistributed as follows:conloc
conloc
attribute (part of the original all-id
attribute list), has been superceded by the more general
value reference facility. The original conloc
attribute
is now simply an application of the value reference facility (see " 6.7.1, Value Reference").context
opacity
attribute, one of the general attributes of the General
Architecture.delims
HyNames
HyNames
attribute is now defined via
the normal architecture use declaration mechanisms defined in the AFDR facility
of the SGML Extended Facilities (see " A.3").
The name "HyNames" is no longer required by the HyTime architecture as documents
are free to use any names they want when configuring the use of an architecture.id
id
attribute is now part of the common
attributes for elements of the General Architecture (see "A.5.2, Common attributes of elements ").notation
notation
attribute is eliminated. The
use of data content notations with elements can now be controlled using the
Data Attributes for Elements (DAFE) facility of the General Architecture (see "A.5.3").activity
activity
element form is replaced by
the actrule
(activity policy
association rule) element form. An activity rule associates elements with
the policy specifications that govern their access according specified activity
types. The HyTime architecture no longer defines a fixed set of activity types,
although it does define a starter set.all-lex
all-lex
attribute list form has been
replaced by the Lexical Type Definition Requirements facility of the SGML
Extended Facilities, see "Annex A.2"
for details.baton
baton
element form can now include progrp
elements, in addition to proscope
elements.all-ref
all-ref
attributes
have been split beween the immediate reference type control facility of the
General Architecture and the reference control facility of the HyTime location
address module. See "A.5.5, ID immediate referent
type control" and "7.7, Reference
control".batrule
evscheds
attribute with the new scheds
attribute and the original pevsched
attribute
with the new targschd
(target schedules) attribute.bibloc
bibloc
form now takes the unique bibsrc
(bibliographic location source) attribute, which points to another
bibliographic location that defines the addressing context for the first bibloc
.calendar
calendar
attribute list has been
superceded and replaced by more complete calibration and calendar specification
facilities. See "9.9, Calibrated real time axes".clink
clink
form
is now formally derived from the new hylink
form. This means that clink
can take all of hylink
's attributes (except anchrole
, which is fixed
for clink
in the HyTime architecture).isbento
, methods
, modgen
and degrade
attributes have been removed. They
are replaced by the more general facilities for formal system identifiers
(FSI), part of the SGML Extended facilities (see "A.6 Formal System Identifier Requirements"), by which any of these
attributes can be defined for specific storage managers. The attributes altreps
and superdcn
are now defined by the General Architecture, which is part
of the SGML Extended Facilities (see "A.5").
The encoding
attribute is now
defined by the FSI facility.dimlist
dimlist
element form has been replaced
by the %dimlist
parameter
entity, which expands to all the possible ways in which dimension specification
lists can be represented.dimref
dimref
element form has been redefined and enhanced
to reflect the new, more generalized event schedule and finite coordinate
space model. In particular, it makes it possible to distinguish references
to modified and unmodified (by rendition processing) extents.dimspec
markfun
(marker function) element form.
As a marker function, dimension specifications can use any marker function
notation, with the default being the HyTime marker list notation.dataloc
dataloc
has been generalized into a general facility for defining
data tokenizers and data parsers and parsing contexts. The dataloc
element form is now a combination of a list location address
with a data tokenizer grove constructor (datatok
).dvl-atts
dvl-atts
attribute
list:dvlist
dvlist
) element form has a new attribute, defatts
(default-setting attributes). This attribute names attributes whose values
become the new default values for attributes controlled by the default value
list. This enables the definition of the propagation rules for attribute values
in combination with the use of default value lists to set the initial values
of implied attributes. This provides what is essentially #CURRENT behavior
for attributes, but down the element tree, rather than sequentially through
the document.event
object
) to address the objects that
they schedule as an alternative to containing them syntactically. The accessed
anchor list mechanism has been replaced by the more general element forms
hyperlink location address (linkloc
)
and hyperlink anchor location address (anchloc
). The new attribute align
(object alignment)
specifies how the object is to be aligned within the extent of the event.evgrp
grpscope
attribute, which has been superceded by more complete event
grouping and control mechanisms.fcs
fcs
element form has
been redefined. Axes are now defined using attributes of the fcs
element, rather than subelements. The original axisdefs
attribute has been replaced by the axes
attribute,
which specifies the names of the attributes of the same element that define
the axes of the coordinate space.The association of FCSes with measurement domains and units has been extended and generalized, including the addition of the ability to calibrate axes according to some real measurement system or event (e.g., you can associate the start of a time axis with a precise point in real time).
You can now use fcs
elements by reference from event schedules, in addition to
having them contain event schedules directly, as was required in HyTime First
Edition.
fcsloc
fcsloc
form can be achieved by defining a notation-specific query notation and using
it with a query location address element. The new and improved fcsloc
addresses scheduled objects by addressing the region of
the coordinate space within which they are scheduled. In essence, the fcsloc
provides a marquee selection (bounding
box) mechanism for addressing scheduled objects. This lets you address whatever
objects happen to fall within a particular portion of a coordinate space (for
example, at a particular time or time span along a time axis).granule
gd
attribute has been replaced by the
granule definition notation (gdnot
) attribute. Granules
can be defined using any notation.HyDoc
unmspace
attribute has been
removed as the concept of unified name spaces has been replaced by the more
general mechanism for defining name spaces with groves. The docdmu
attribute has been replaced by new facilities for defining finite
coordinate spaces (see "9, scheduling module").ilink
ilink
form, two new hyperlink forms have been added, hylink
(hyperlink) and varlink
(variable link). These three forms provide the three possible
syntax configurations for addressing anchors. hylink
uses one attribute per anchor role while varlink
uses one subelement (anchspec
) to address the members of each anchor. ilink
still uses the single linkends
attribute
to address the anchors of the link.The endterms
and aggtrav
attributes have been eliminated. The HyTime
architecture no longer has an opinion on the issue of anchor description and
the whole concept of aggregate locations has been replaced by the grove addressing
model and the new agglink
hyperlinking
form (which is derived from hylink
).
The hyperlink traversal rule attributes intra
and extra
have been replaced by a single attribute, linktrav
. In addition, traversal among
the members of an anchor is controlled with the new attribute, listtrav
.
locsrc
cantcnst
defines the behavior when a grove cannot be constructed from the
location source.The location source can be omitted for any location
address that is not an intermediate rung in a location ladder. For all location
address forms except mixedloc
and nameloc
(which don't take the locsrc
attribute), when the locsrc
attribute is omitted, the
location source is defined according to the settings of the implied location
source attributes (impsrc
). By
default, the implicit location source is the non-location-address element
that directly or indirectly addresses the location ladder of which the location
address is the top (or only) rung.
markfun
marklist
marklist
element form has been replaced
by the %marklist
parameter
entity, which expands to all the possible ways in which marker lists can be
represented.multloc
aggloc
has been eliminated
from the multloc
attribute list. The concept of aggregate
locations has been replaced by a clearer definition of multi-object anchors
and by the agglink
hyperlinking
form.nameloc
nameloc
form
is now formally derived from the new mixedloc
element form, which has the semantic of addressing whatever
the location address elements in its content address.nmlist
nmlist
element
form is now formally derived from the new nmsploc
(name space location address) element form. The nmsploc
form provides the ability to
address nodes in any named node list in any grove.The obnames
and dtdorlpd
attributes have been eliminated.
The function of obnames
has been subsumed by the implications
of grove-based addressing and the general semantics of location addresses.
The dtdorlpd
attribute has been replaced by the active
data attribute defined by the SGML
notation, which is defined as part of the definition of the SGML property
set (see "A.7, SGML property set").
nmquery
queryloc
element
form. It maintains the original qdomain
attribute from
the original query
attribute list but it's now simply a
renaming of the normal locsrc
attribute. It also takes
the new attribute notfound
, which indicates the behavior
when the query fails to find any nodes.proploc
proploc
(property location address) form has been updated to reflect the new grove
model. It now addresses the value of the property of a node in a grove by
property name. The attribute joint
is no longer relevant
and has been eliminated. A new attribute, direct
, lets you address either the direct value of a property or
the effective value resulting from the application of the value reference
facility (see "Value Reference").rendrule
apporder
is eleminated as
the ordering of rendition rules is inherent in their grove representation.relloc
relloc
)
element form has been refined. The original attribute root
has been replaced by the normal meaning of the location source attributes
(in particular, the new implied location source facility means that an omitted
location source is, by default, the root of the primary tree, which is what
the root
attribute meant). The new attribute starting node
(strtnode
) addresses the node whose relatives are being
addressed.sched
fcs
(governing finite coordinate space), coverage
(extent coverage), and overlap
(is overlap allowed?). The
attribute apporder
is eleminated as the ordering of events
is inherent in their grove representation.spanloc
spanloc
attribute of the spanloc
attribute list has been redefined to remove the spanlink
keyword. Span addressing has been formalized and clarified
as well.wand
wand
element form can now include modgrp
elements, in addition to modscope
elements.abstime
abstime
element form has been
superceded and replaced by more complete calibration and calendar specification
facilities. See "9.9, Calibrated real time axes".accanch
linkloc
) and hyperlink
anchor location address (anchloc
).
These location addresses can be used with events to associate an event with
a link or one of its anchors. Specific applications could also define more
specialized queries for expressing the semantic relationship between events
and hyperlinks and their anchors (or any other addressible object for that
matter).axis
axis
element form has been eliminated.
The axes of finite coordinate spaces are now defined directly by attributes
of the fcs
element.date
date
element form has been superceded
and replaced by more complete calibration and calendar specification facilities.
See "9.9, Calibrated real time axes".docmdu
docmdu
attribute has been eliminated
as it is replaced by facilities of the redesigned finite coordinate space
mechanism.exrecon
grprepet
repscope
attribute for controlling the repetition
of an event group. juledate
juldate
element form has been
superceded and replaced by more complete calibration and calendar specification
facilities. See "9.9, Calibrated real time axes".lexmodel
lexmodel
form has been replaced by the
more general Lexical Type Definition facility (see "A.2, Lexical Type Definition Requirements (LTDR) ").lexord
lexord
form has been replaced by the
more general Lexical Type Definition facility (see "A.2, Lexical Type Definition Requirements (LTDR) ").mallobj
mrkquery
notloc
queryloc
(query
location address) element form. The difference between these two is that the
results of a notation-specific location address were undefined, while the
results of a query location address must be nodes in a grove. However, a query
location address can still use any query notation.pls2gran
profun
expro
element form.propdef
pulsemap
query
queryloc
(query location
address) element form. The original qdomain
and qcontext
attributes are replaced by the general facilities for defining
and addressing location sources.scaleref
scaleref
element form has been
superceded and replaced by more complete projection specification facilities.
See "10.3, Projection".select
timeoff
timeoff
element form has been
superceded and replaced by more complete calibration and calendar specification
facilities. See "9.9, Calibrated real time axes".The mechanism for declaring the use of the HyTime architecture and specifying the modules and features needed by a document has been changed to reflect the new enabling architecture facility defined in "A.3, Architectural Form Definition Requirements (AFDR) ", part of the SGML Extended Facilities. In general, the use of processing instructions has been replaced by the use of data content notation declarations and data attributes, except for the architecture use declaration processing instruction, provided by Ammendment 1 to ISO/IEC 10744:1997.
A new set of facilities, the SGML Extended Facilities have been defined. The SGML Extended Facilities provide functions that the HyTime architecture needs but that are general to all SGML applications, not just hypermedia. The new facilities are:
lextype
attributes from the base
module.The architectures defined in ISO/IEC 10744:1997 and ISO/IEC 10179 (DSSSL) conform to this clause.
The reference location address facility of the location address module
enables the direct use of any addressing method from attributes of elements,
rather than using indirect addressing. This includes the ability to use query
location addresses. This means you can use any form of query directly from
elements in a way that is meaningful and well defined in a larger HyTime framework.
This enables, for example, the declaration of the HTML A
element as a conforming HyTime contextual link. See "7.8, Reference location address".
The implied location source facility allows you to create indirect location addresses that do not address their location sources explicitly. This enables, for example, location addresses that are relative to the non-location-address elements that use them. It can greatly simplify the syntax of location addresses. See "7.3, Implied location source".
The calibration facility of the scheduling module makes it possible to calibrate time axes of finite coordinate spaces in terms of real measurements, such as real time. This facility replaces and generalizes the original calendar specification facility. See "9.3.1, Axis calibration", and "9.9, Calibrated real time axes".
agglink
agglink
form, along with a clearer definition of multi-object anchors,
replaces the original aggregate link concept. Any existing nameloc
element that used the aggloc
attribute can
be redefined as an agglink
without modifying element
instances.agrovdef
anchloc
batonseq
bosdatt
inbos
), what it's processing priority is (bosprrty
),
and whether or not it's a sub hub document (subhub
).bosspcat
bosspec
attribute for the HyTime document element. The bosspec
attribute points to bosspec
elements
in the same document that modify the inclusion or exclusion of entities in
the HyTime BOS.bosspec
datatok
datatok
element form is the data tokenizer grove constructor. It can be used to define
data tokenizer groves not provided by the dataloc
element form (which combines a data tokenizer with a list
location).dimpro
expro
profun
element form.grovplan
hylink
ilink
form in that it uses separate attributes to address the anchors
of the link, one for each anchor. The original clink
and new agglink
forms are derived from the hylink
form.impsrc
linkloc
mixedloc
mixedloc
form is the base from which the nameloc
form is derived.modgrp
wand
.modified
nmsploc
nameloc
) elements.pgrovdef
prorule
progrp
proseq
queryloc
notloc
(notation-specific location address) form. Query location
addresses differ from notation-specific location addresses in that the results
of resolving a queryloc
query
must be nodes in a grove. This makes all HyTime location addressing closed
over nodes in groves while enabling the clean and clear integration of any
addressing method into a HyTime framework.refloc
varlink
hylink
and ilink
by using subelements to define and address each anchor, rather than using
attributes of the link element. It does not require that the anchor roles
be fixed within a link type. The XML Link extended
element
form can be derived from the varlink
form.dataloc
element form is defined.anchloc
location address element form.dataloc
element form.dataloc
element form.linkloc
location address element form.
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