M. A. Najork and E. Golin. Enhancing Show-and-Tell with a polymorphic type system and higher-order functions. In Proc IEEE Workshop on Visual Languages, Skokie, IL, pages 215-220, 1990.  Home/Search   Document Not in Database   Summary   Related Articles   Check

....in its own right. The approach used a translation from Haskell into an intermediate form VHIF with visual equivalents for each syntactic production of VHIF. The syntax of VHIF is close to Haskell s. It uses visual notations of the box and arrow style. Visual Haskell is closest to Show and Tell [39]. Show and Tell is also declarative in nature, and utilizes a polymorphic type system similar to Haskell s. But Visual Haskell is incomplete, lacking syntax for modules, type declarations, type classes and instances, arrays, and user de ned operators. U. Schreiweis [51] introduced an integrated ....

....that have an explicit notion of types. They can be divided into two categories: those whose type system are modeled after traditional procedural languages e.g. Fabrik [25] and DataVis [20] and those whose type systems are based on the Hindley Milner approach, e.g. Enhanced Show and Tell [39], Cube [40, 41] VisaVis [45] and an extension of Forms 3 [10] In the rst category, the languages supply a set of prede ned types such as arrays, records, enumerations, bitmaps, etc. but do not allow the user to de ne new types. For example in DataVis, types are associated with colors. Only ....

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M. A. Najork and E. Golin. Enhancing Show-and-Tell with a polymorphic type system and higher-order functions. In Proc IEEE Workshop on Visual Languages, Skokie, IL, pages 215-220, 1990.

....would not be detected. 2.3.1. Static Types in VPLs Our search through VPL literature has revealed only seven VPLs that have incorporated static type inference. In about half of these VPLs, systems like Milner s are fully incorporated into the VPL, and hence static soundness is preserved. ESTL [30] and CUBE [31] are VPLs in this category. For example, Milner s type system has been incorporated into ESTL as follows. ESTL, an extended version of the dataflow VPL Show and Tell [32] has a feature termed consistency, with which values can be compared, conditions tested, etc. If such conditions ....

M. Najork & E. Golin (1990) Enhancing Show-and-Tell with a polymorphic type system and higher-order functions. IEEE Workshop on Visual Languages. Skokie, Illinois, October.

....are based is called pipeline dataflow . The combination of a visual interface with pipeline dataflow is well established in several fields, including signal processing [88, 12, 85] image processing and visualisation [112, 83] instrumentation [82] and general purpose visual programming languages [99, 59]. Signal processing systems are based on a special class of pipeline dataflow, dataflow process net1 CHAPTER 1. INTRODUCTION 2 Dataflow process network let u = copyV k 0 in scanS ( u High level language Visual language Programming technology Computational model Figure 1.1. A conceptual ....

....explicit data dependencies throughout the whole program. Of particular interest in Visual Haskell is the way it handles higher order functions: because Visual Haskell is curried, higher order functions are as easy to construct as firstorder functions. There is no need for special function slots [99], and no enforced distinction between first order and higher order functions as in VisaVis [110] Any construct a case87 CHAPTER 4. VISUAL HASKELL 88 expression, say can be a function, and can be applied in the same way as a named function. The next two sections briefly survey work on visual ....

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Marc A. Najork and Eric Golin. Enhancing Show-and-Tell with a polymorphic type system and higher-order functions. In Proc. 1990 IEEE Workshop on Visual Languages, Skokie, Illinois, pages 215--220, October 1990.

....are based is called pipeline dataflow . The combination of a visual interface with pipeline dataflow is well established in several fields, including signal processing [88, 12, 85] image processing and visualisation [112, 83] instrumentation [82] and general purpose visual programming languages [99, 59]. Signal processing systems are based on a special class of pipeline dataflow, dataflow process net1 CHAPTER 1. INTRODUCTION 2 Dataflow process network let u = copyV k 0 in scanS ( u High level language Visual language Programming technology Computational model Figure 1.1. A conceptual ....

....explicit data dependencies throughout the whole program. Of particular interest in Visual Haskell is the way it handles higher order functions: because Visual Haskell is curried, higher order functions are as easy to construct as firstorder functions. There is no need for special function slots [99], and no enforced distinc88 CHAPTER 4. VISUAL HASKELL 89 tion between first order and higher order functions as in VisaVis [110] Any construct a case expression, say can be a function, and can be applied in the same way as a named function. The next two sections briefly survey work on visual ....

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Marc A. Najork and Eric Golin. Enhancing Show-and-Tell with a polymorphic type system and higher-order functions. In Proc. 1990 IEEE Workshop on Visual Languages, Skokie, Illinois, pages 215--220, October 1990.

....We represent individual functions as graph nodes; the application of a function to an argument sub expression is represented by an arc between nodes. This is the most common representation for functional languages in the Visual Programming literature, and is used in various forms in [3] [4] and [6] The basic unit of program construction in our representation is the expressiongraph: a function that has been applied to zero or more arguments. An expressiongraph has an implicit value (which may be a ground data value or may be function valued) and an explicit type. Two advantages of ....

....practice in any case. VisaVis, introduced in [6] has been extended with an implicit incremental type system that allows a form of parametric polymorphism and function overloading [5] Show and Tell, a visual teaching language, has also been extended to include an explicit polymorphic type system [4]. The proposed representation is based on Haskell s type system, with its parametric polymorphism and type class overloading scheme. 2 Anatomy of an expression graph In this section we describe the visual syntax of our representation, starting with the basic arc node structure. Figure 1 shows a ....

M. Najork and E. Golin. Enhancing Show-and-Tell with a polymorphic type system and higher-order functions. In Proceedings of the 1990 IEEE Workshop on Visual Languages, pages 215--220. IEEE Computer Society Press, 1990.

....the same generality in which LISP treats its programs and data. This paper describes such a language. 2. Previous Work Some earlier data flow visual programming languages have provided for higher order functions, including CUBE[Najo91] DataVis[Hils91] VPL[Lau91] Enhanced Show and Tell (ESTL) [Najo90], and Show and Tell [Kimu86] Higher order functions have been represented in two ways in data flow visual programming languages. The first approach uses function slots inside icons for higher order functions, into which lower order functions are slotted in. DataVis, CUBE, and ESTL use this ....

Najork, M.A., Golin, E. "Enhancing Show-andTell with a polymorphic type system and higher order functions," Proceedings of IEEE Workshop on Visual Languages, Skokie, Illinois, 1990, pp. 215-220.

....is present in expression graphs. Kelso s general purpose system[Kel94] and Addis and Addis functional schematic programming language Clarity [AA96] both label expression graphs with polymorphic types which are resolved incrementally during interconnection. Najork and Golin s Enhanced Show and Tell[NG90] is a visual data flow language which incorporates polymorphic type checking. Expression graphs are composed in part from typed icons for data sources. While type determined component interconnection ensures type consistency, it may be useful to explain why a proposed connection is inappropriate, ....

M. A. Najork and E. Golin. Enhancing Show-and-Tell with a polymorphic type system and higher-order functions. In Proc IEEE Workshop on Visual Languages, Skokie, IL, pages 215--220, October 1990.

.... of this type of system [7] and a number of systems based on this idea have been successful, both in signal processing and in other fields such as image processing and instrumentation [9] In the field of visual language research, Visual Haskell is perhaps closest to that of Najork and Golin [8] on Show and Tell. Show and Tell is also declarative in nature, and utilises a polymorphic type system similar to Haskell s. Visual Haskell s argument slots were inspired by Show and Tell s typing slots their type notation would be a good starting point for Visual Haskell s missing typing ....

M.A. Najork and E. Golin. Enhancing Show-and-Tell with a polymorphic type system and higher-order functions. In IEEE Workshop on Visual Languages, Skokie, Illinois, pages 215--220, October 1990.

....denotes the type of Y On F, due to membership in F, or due to membership in a cell group on F. N F denotes referenceable object N on form (or referenceable object) F. Table 1: Notation Milner s are fully incorporated into the visual language, and soundness and completeness are preserved. ESTL [6], CUBE [7] and VisaVis [9] are systems in this category. ESTL, for example, supports tuple types, union types, function types, higher order functions, and polymorphic types. The entire type system is visible to the user, including the polymorphic type variables. The second category, which ....

M. Najork, E. Golin, Enhancing Show-and-Tell with a polymorphic type system and higher-order functions, IEEE Wkshp. on Vis. Langs., Skokie, IL, Oct. 1990.

....increase the potential for code reuse. Strangely enough, though, almost all visual languages are first order, and thereby miss out on this powerful abstraction mechanism. In fact, to our best knowledge, we were the first to propose the use of higher order functions in the data flow framework [56]. 1.4 Arguments for a 3D Notation Six years ago, Ephraim Glinert speculated about the prospects and potential benefits of threedimensional visual programming: But first, why do we advocate programming in three dimensions Many readers will surely argue . that we don t yet know how to ....

.... visualized to provide feedback to the user (in this respect, Cube is more user friently than most textual languages that use Hindley Milner; typically, they do not provide such feedback) To our best knowledge, we were the first to incorporate the Hindley Milner algorithm into a visual language [56], and to make strong guarantees about type safety in a visual setting. Horn logic was first proposed as a programming language by Robert Kowalski, whose seminal book Logic for Problem Solving [40] laid the foundations for an entire branch of programming language research, namely logic ....

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Marc A. Najork and Eric J. Golin. Enhancing Show-and-Tell with a polymorphic type system and higher-order functions. In IEEE Workshop on Visual Languages, pages 215 -- 220, Skokie, IL, October 1990.

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