Visual Programming
Rationale
Despite the clear potentialities of computer systems, people missing a
computer-science background often show a hostile attitude towards them.
This is generally due to the fact that textual programming languages and
operating system shells are seldom intended to fit the user's mental
representation of problems. They rather obligate users to 'move' towards
computers, and force them to acquire the needed knowledge through
intermediate learning media (mainly written material) with considerable
efforts.
Visual Languages for computers originate from the attempt to
improve man-machine interaction through a better use of human eyesight,
and use images to convey meanings.
Visual Programming Languages, in particular, allow users to specify
programs by means of a set of graphic symbols, properly interconnected in a
space of 2 (or more) dimensions.
Visual Query Languages, then, can make database querying more
easy and effective.
Major Ongoing Projects:
VIPERS (VIsual Programming Extensible and Reconfigurable
System) is a new general-purpose visual programming environment
built at the University of Pavia.
The system runs on UNIX workstations under the X Window system: its
primary aim is to allow users of different programming skill (including non-
programmers) to easily develop applications of disparate domains without
being forced to focus their attention on the programming activity itself.
According to the data-flow model, VIPERS programs are graphs in which
data tokens travel along arcs between nodes (modules) that transform data
tokens themselves.
The novel design peculiarity of VIPERS is the use of a fully programmable
interpretive command language (Tcl) to define the flow graph operators,
as well as to control the behaviour and the appearence of the whole
programming environment.
Our strategy is mainly aimed at simplifying as much as possible the
application developers' tasks so as to encourage the utilization and
the customization of the system.
Furthermore, the potential advantages deriving from the communication
cabilities of the system still need to be fully investigated, and represent
a subject for future research.
For more info, please, mail to
vipers@ipvvis.unipv.it
The MARMOTTA system serves as a graphical interface for querying
remote databases which have already been provided with a software layer
to communicate with the WWW world. It can be used as a convenient
alternative to the forms embedded within the WWW-clients.
Within Marmotta, icons are used to present the domain of interest
and the retrieval requests in an original way, and are managed by the user
in a direct manipulation style. The ease-of-use characterizing form-based
interfaces is preserved (users need not know the structure of the database)
while expressive power is greatly increased. Moreover, Marmotta
provides comfortable mechanisms for browsing, manipulating and reusing
queries results as well as previous queries, thus strongly supporting
non-monotonic, progressive query processes.
For more info, please, mail to
marmotta@ipvvis.unipv.it
Last modified: 13 July 95
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