Abstract not found

This thesis presents and justifies a framework for programming real-time signal processing systems. The framework extends the existing "block-diagram" programming model; it has three components: a very high-level textual language, a visual language, and the dataflow process network model of computation. The dataflow process network model, although widely-used, lacks a formal description, and I provide a semantics for it. The formal work leads into a new form of actor. Having established the semantics of dataflow processes, the functional language Haskell is layered above this model, providing powerful features---notably polymorphism, higher-order functions, and algebraic program transformation---absent in block-diagram systems. A visual equivalent notation for Haskell, Visual Haskell, ensures that this power does not exclude the "intuitive" appeal of visual interfaces; with some intelligent layout and suggestive icons, a Visual Haskell program can be made to look very like a block dia...

Research in the origins and evolution of language has now reached a level where languages with grammatical structures are emerging in computer simulations and robotic experiments based on situated embodied language games played by populations of agents. This paper focuses on some of the technical AI issues related to this research. Specifically, we report on a system for planning complex meanings (IRL) and on their grammatical expression in Fluid Construction Grammar.

In this paper, the uses of types and type inference in visual languages are explored. First, we discuss how the goals of a type system must differ for visual languages from those of a type system for textual languages. We then present a type system developed under these goals for the visual language Forms/3. Within the context of this system, issues of particular importance in visual languages are examined, including maintaining the user's conceptual model, the avoidance of language restrictions solely to support a type system, and how the visual process of programming can provide additional information to the type system. 1: Introduction One approach to types in visual programming languages (VPLs) is to hide them. The rationale would be to keep the simple, flexible spirit of programming in a visual language. This philosophy appears to be shared by many researchers, because few have introduced the concept of types into visual languages. But it seems contradictory to allow the user to u...

I declare that this thesis is my own account of my research and contains as its main content work which has not previously been submitted for a degree at any tertiary education institution. Joel Kelso ii The purported advantages of Visual Programming, as applied to general purpose programming languages, have remained largely unfulfilled. The essence of this thesis is that functional programming languages have at least one natural visual representation, and that a useful programming environment can be based upon this representation. This thesis describes the implementation of a Visual Functional Programming Environment (VFPE). The programming environment has several significant features. • The environment includes a program editor that is inherently

Data flow based visual programming languages are an active area of research in visual programming languages. Some recent data flow visual programming languages have implemented higher order functions, allowing functions to be passed to/from functions. This paper describes a data flow visual programming language in which the first class citizenship of programs have been taken a step further, and programs can be manipulated as data with the same kind of flexibility that LISP offers in manipulating programs as data. 1. Introduction It is widely accepted that higher order functions provide a substantial amount of power and flexibility to programming languages which support them. The ability to pass functions to and from functions allow for the creation of general functions which can easily be adapted to a variety of situations. Thus, programming languages like ML[Miln84] and Miranda[Turn90] are fully higher order - functions can be passed into and returned out of functions. Although the ...

We describe the visual model of Cordial, a visual language integrating ObjectOriented and Constraint programming. The motivation behind Cordial is to provide a clear notion of objects defined implicitly by means of constraints. Cordial is a visual language having three distinguished features: (1) A hierarchical visual model, (2) an underlined visual formalism giving precise syntax and static semantics of visual programs and (3) a dynamic semantic model based on a formal calculus integrating objects and constraints. The visual model consists of a hierarchy of layers of visual representations of object oriented concepts in which icons can be "expanded" up to the underlined visual formalism, an extension of Harel's Higraphs ([Har88]). We present here the visual model, provide its formal translation into Higraphs, and describe the visual syntax and semantics of Cordial. Keywords: Visual language, Cordial, constraint programming, object oriented programming, visual formalism, iconic programming. 1

This thesis presents and justi es a framework for programming real-time signal process-ing systems. The framework extends the existing \block-diagram " programming model� it has three components: a very high-level textual language, a visual language, and the data ow process network model of computation. The data ow process network model, although widely-used, lacks a formal description, and I provide a semantics for it. The formal work leads into a new form of actor. Having established the semantics of data ow processes, the functional language Haskell is layered above this model, providing powerful features|notably polymorphism, higher-order func-tions, and algebraic program transformation|absent in block-diagram systems. A visual equivalent notation for Haskell, Visual Haskell, ensures that this power does not exclude the \intuitive " appeal of visual interfaces � with some intelligent layout and suggestive icons, a Visual Haskell program can be made to look very like ablock diagram program. Finally, the functional language is used to further extend data ow process networks, by simulating timed and dynamically-varying networks.

Lograph is a non-deterministic visual logic programming language which provides the basis for the language LSD, a visual language for designing structured objects. Hence in order to implement LSD we must first implement Lograph. This raises many questions about visual logic programming languages, such as efficient execution, and clarity of the interface. Here we show how Lograph can be made deterministic and potentially efficient by ordering execution rules, cases of definitions and literals within cases and queries. We also discuss the conflict that arises between this ordering for efficiency and the clarity of programs, and present an interface mechanism to overcome it. Finally, we describe a prototype of Lograph which is currently under development.

Designs of complex objects often include parameters which, when given values, provide a realisation of a specific example of the design. Such parametrised designs, therefore, actually represent families of objects. In order to provide the programming capabilities necessary for building such parametrised designs, some Computer-Aided Design systems include programming languages or provide interfaces to them. This creates a sharp division in the design process between designer and programmer.