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From: rasure@sherman.unm.edu (John Rasure)
Newsgroups: comp.graphics.visualization,comp.lang.visual
Subject: Terminology for discussing next generation visual languages
Message-ID: <1990Nov14.192736.660@ariel.unm.edu>
Date: 14 Nov 90 19:27:36 GMT
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Organization: University of New Mexico, Albuquerque
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The following is in response to Craig Upson's posting requesting criticism of
first generation systems and proposals for the second generation.

Along with making a wish list of specific features that could be added
to first generation systems, we need to think about the infrastructure
for the next generation systems.

The following is a proposed list of components that should be considered
in the design of a second generation data flow oriented visual language
programming environment.  Our motivation for posting this is two-fold:
1) we would like to test our terminology and see if it is reasonable and
2) provide a basis for comparison of the various data flow oriented
visual systems.

	1.  User Interface
		a)  programming paradigm (data flow, forms/menus)
		b)  workspace/visual editor
		c)  access to language primitives (selection of operators)

	2.  Visual Programming Language Specification
		a)  syntax (graphical/lexical elements)
		b)  semantics (meaning of elements)
		c)  expression evaluation (setting operator parameter) 
		d)  hierarchy (visual complexity)
		e)  documentation (program explanation)

	3.  Operating System Supporting the Visual Language
		a)  compiler/interpreter (prototyping vs. production)
		b)  computational model (demand or data-driven)
		c)  scheduling (static vs. dynamic, parallel vs. serial)
		d)  execution mode (continuous or triggered execution)
		e)  data transport model (representation - files, pipes,
				      shared memory, sockets, streams, blocks)
		f)  debugging support (preventing errors, correcting errors)
		g)  recoverability (saving program state)

	4.  Library of Operators
		a)  application domain
		b)  level of abstraction
		c)  interface specification (executable or linkable)
		d)  interoperability  (data compatibility)

	5.  Development Support for Retargeting/Extending
		a)  user interface development system
		b)  data token description and typing 
		c)  operator code generation
		d)  configuration management

John Rasure and Carla Williams
rasure@bullwinkle.unm.edu or carla@bullwinkle.unm.edu
--
------------------------------------------------------------------
Dr. John Rasure                    rasure@bullwinkle.unm.edu
Department of EECE
University of New Mexico           Albuquerque,    NM 87131