Dan Rubin's SuperfluousBanter

Syntax, Semantics and Pragmatics in Hypertext Documents

What are we talk­ing about? Seman­tics is a topic that has been much dis­cussed
last year and still remains an impor­tant issue (although it’s becom­ing
some­what of a buzz­word. Hype or real­ity?). This post is not aimed at dis­cussing
the value or impor­tance of seman­tics as such, but rather its gen­eral frame­work
and its appli­ca­tion to hyper­text doc­u­ments and web sites in general.

Semi­otics

Semi­otics is com­monly known as the gen­eral sci­ence of signs. Semi­otics is com­posed
of three aspects: a syn­tac­ti­cal aspect (syn­tax or syn­tac­tics), a seman­tic aspect
(seman­tics) and a prag­matic aspect (pragmatics).

Syn­tac­tics (Syntax)

Dif­fer­ent forms of data exchange are con­sti­tuted of signs or com­bi­na­tion of
signs (lan­guage, code, non-verbal signs — among oth­ers). Syn­tax defines
a set of rules to be applied when exhang­ing data, thus “the rela­tion­ship
of signs to what they stand for”. Break­ing these rules results in a syn­tac­ti­cal
dis­tur­bance. An exam­ple of this type of dis­tur­bance in human data pro­cess­ing
are spelling errors.

For exam­ple, using an ele­ment spelled <stronk> instead of
<strong>. But also ommit­ing a clos­ing tag on empty ele­ments
such as <img>. The related DTD
(Doc­u­ment Type Def­i­n­i­tion) or more recently a Schema
(XML)
con­tains the rules that define the cor­rect spelling or appli­ca­tion of (the signs
that con­sti­tute) an ele­ment (note: in XML the num­ber of ele­ments are unlimited).

Seman­tics

Seman­tics applies to the mean­ing of data. When exchang­ing data sender and receiver
will have to assign the same mean­ing to par­tic­u­lar (com­bi­na­tions of) signs,
thus “the rela­tion of signs to the objects to which the signs are applic­a­ble”.
If this con­di­tion is not respected a seman­tic dis­tur­bance will occur. An exam­ple
of the above men­tioned dis­tur­bance is a dis­cus­sion between two indi­vid­u­als not
being able to under­stand each other.

The mean­ing (or con­text) of spe­cific ele­ments is what we com­monly refer to
as the seman­tic value of code. There­for the use of <p> ele­ments
is jus­ti­fied in the con­text of a para­graph and like­wise <hn>
n{1,6} ele­ments are used to rep­re­sent head­ers in a doc­u­ment. Fur­ther­more ele­ments
have to be nested cor­rectly. For exam­ple — in a (X)HTML doc­u­ment —
an <h1> ele­ment can not con­tain a para­graph. The DTD or Schema
explicitely con­tains nest­ing rules. How­ever it can not eval­u­ate if the con­text
of a par­tic­u­lar ele­ment is seman­ti­cally cor­rect. Cur­rent val­ida­tors check a
doc­u­ment for syn­tac­ti­cal errors, but remain lim­ited in their apti­tude to dis­cern
issues related to seman­tics. The ques­tion remains if it’s tech­ni­cally
pos­si­ble to build an analy­sis tool spit­ting out sug­ges­tions regard­ing the seman­tic
value of a doc­u­ment. Dan Ceder­holm started
a prac­ti­cal ini­tia­tive known as Sim­ple­Quiz
— dis­cussing the seman­tic value of ele­ments in hyper­text documents.

Prag­mat­ics

This aspect describes the effect a par­tic­u­lar sig­nal has on the behav­iour
of the receiver, thus the “rela­tion of signs to (human) inter­preters”.
If the effect is dif­fer­ent from the senders ini­tial inten­tion a prag­matic dis­tur­bance
occurs. A suit­able exam­ple are speed delim­iter signs found on most roads, with
var­i­ous applic­a­ble val­ues. No spelling errors have been made and the data is
cor­rectly inter­preted by both sender and receiver — yet some dri­vers ignore
this sig­nal by speeding.

Prag­mat­ics relate to some extend to usabil­ity. How will a user (receiver) act
or react to a given con­di­tion, sit­u­a­tion or sig­nal (sender). It’s become
best prac­tice to avoid under­lin­ing reg­u­lar text in doc­u­ments (empha­sis), and
reserve this prac­tice exclu­sively for hyper­links. Abstract­ing from con­text,
syn­tax nor seman­tics for­bid the above men­tioned prac­tice. How­ever, under­lin­ing
text that is not a hyper­link (or ommit­ing to under­line a hyper­link) results
in a prag­matic dis­tur­bance — users expect a hyper­link to be under­lined
(and vice versa).

Resources:

• “Effec­tive Dia­gram­matic
  Com­mu­ni­ca­tion: Syn­tac­tic, Seman­tic and Prag­matic Issues”, C. A.
  Gurr (1999).
• “Towards
  The Seman­tic Web”. J. Davies et al (2002).
• “Semi­otics:
  A Primer for Design­ers”, C. Hodge (2003).
• Assorted courses (i.e. infor­ma­tion man­age­ment, pro­cess­ing and design) fol­lowed
  dur­ing my MSc
  degree at Eras­mus Uni­ver­sity Rot­ter­dam, The Nether­lands (2003).

This item was posted by dhilhorst on Wednesday, January 28th, 2004.

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