R. Helm and Kim Marriott. A declarative specification and semantics for visual languages. Journal of Visual Languages and Computing, 2:311--331, 1991.  Home/Search   Document Not in Database   Summary   Related Articles   Check

....far more intuitive representation for capturing domain specific notations and abstractions. 2. 2 Visual languages There are many approaches to the specification and recognition of visual languages including grammarbased [23] first order) logic based [11] graph grammars [21] constraint based [13], etc. see [20] for a survey of these approaches) In this section we will concentrate on the area of environments for the definition of visual languages as they typically include those tools that are essential to specify, recognize, create and interpret instances of these languages. Ptolemy [5, ....

R. Helm and Kim Marriott. A declarative specification and semantics for visual languages. Journal of Visual Languages and Computing, 2:311--331, 1991.

....that recognize the language structures in a relatively unstructured collection of input data. Closer to our approach in the style of specification, though very different in the way it is processed, are those parsing algorithms that operate on a set of constraints rather than a grammar, e.g. [8], 4] Another approach to the specification of visual languages is through the use of first order or other forms of mathematical logic. Here spatial logics are used to define the different possible topological relationships between objects. This approach has the benefit of allowing both the ....

R. Helm and Kim Marriott. A declarative specification and semantics for visual languages. Journal of Visual Languages and Computing, 2:311--331, 1991.

....presumed to be non context free into a context free formalism. Recent work in visual language theory has included a series of alternative frameworks including Positional Grammars (Chang 1988) Costagliola et al. 1991) Picture Layout Grammars (Golin and Reiss 1989) Constraint Set Grammars (Helm and Marriott 1991); Relation Grammars (Crimi et al. 1991) and Relational Grammars (Wittenburg et al..1991; Wittenburg 1992, 1993, 1996) One influence on some recent work in this area has come from constraint logic programming, which is evident in Helm and Marriott s work among others. Loosely speaking, a sign of ....

Helm, R., and Marriott, K. (1991) A Declarative Specification and Semantics for Visual Languages, Journal of Visual Languages and Computing 2:311-331.

....1 1 Introduction If one constructs a pictorial representation of some domain, it is necessary to have effective methods for constructing the relationship between aspects of the pictures and the corresponding aspects of the application domain. The use of a picture specification language [4] the normal method in a computational setting for specifying new classes of pictures according to the requirements of the application domain is not based on an understanding of the cognitive issues involved in the semantics of pictures and in the use of the pictures for a better grasp of ....

Richard Helm and Kim Marriott. A declarative specification and semantics for visual languages. Journal of Visual Language and Computing, 2:311--331, 1991.

....pictures for applications such as document preparation, visualization, pretty printing, visual languages, etc. Some of the picture definition languages include languages based on attribute grammars such as [5, 1] procedural descriptions like [11] or constraint based declarative languages such as [9, 21, 23]. Constraints have been successfully used in graphical interfaces such as [3, 15] and are very natural in expressing spatial relationships among graphical constructs. We define a constraintbased declarative picture specification language (Vodl) where each picture is defined in terms of its ....

R. Helm and K. Marriott. A declarative specification and semantics for visual languages. Journal of Visual Languages and Computing, 2:311--331, 1991.

....appearances of syntactic units. By syntactic units we mean the visual building blocks required to construct visual programs. The advantages of a declarative style are the hiding of low level geometric details from the specifier and the ease of defining spatial relationships among visual objects [8, 2, 1]. VODL addresses three major aspects of visual specification: ffl primitive visual object definitions ffl composite visual object definitions ffl visual layout definition We refer to visual object definitions as vods. Primitive vods serve as a small foundational 4 VISUAL OBJECT DEFINITION ....

....which makes it impossible to provide built in vods suitable for arbitrary languages. The compose operator allows for the definition of new vods which also helps keep the set of pre defined (primitive) vods small. The compose operator is similar to the picture specifications defined in [8], where a picture is defined in terms of visual objects and the relationships among them. The relationships are similar to Golin s [6] shape composition operators, which define spatial relationships among objects. These operators are used in shape compositions to combine two elements. Our compose ....

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R. Helm and K. Marriott. A declarative specification and semantics for visual languages. Journal of Visual Languages and Computing, 2:311--331, 1991.

.... However, we like to mention a few approaches: generalizations of attributed grammars (e.g. picture layout grammars [20] positional grammars (e.g. 21] and graph grammars (e.g. 22, 23, 24] Other approaches closely related to this one use (constraint) logic or relational formalisms (e.g. [25, 26, 27, 28, 29, 30]) to represent spatial relationships. Experience has shown (reported by Wittenburg in [29] that some grammar approaches have limitations (e.g. no arbitrary ordering of input, only special relations allowed, connected graphs necessary, bottom up International Workshop on the Theory of Visual ....

....input, only special relations allowed, connected graphs necessary, bottom up International Workshop on the Theory of Visual Languages, Gubbio, Italy, May 1996 parsing applicable, no ambiguous grammars, etc. which are sometimes unacceptable for particular application domains. Helm and Marriott [26] developed a declarative specification and semantics for VLs. It is based on definite clause logic and implemented with the help of constraint logic programming. Marriott s recent approach is based on these ideas but utilizes constraint multiset grammars [30] An advantage of our approach is the ....

R. Helm and K. Marriott, "A Declarative Specification and Semantics for Visual Languages", Journal of Visual Languages and Computing, vol. 2, no. 4, pp. 311--331, Dec. 1991.

....are an extension to string based grammars in which composition relations other than just string concatenation are allowed. They are a member of a wide ranging family of higher dimensional grammar frameworks, e.g. array, tree, or graph grammars [Ros90] or unification based constraint grammars [Hel91]. Where string grammars generate or compose expressions consisting of one dimensional arrays of symbols, these higherdimensional grammars deal in structures characterized by, for example, geometric positions in two or three dimensional space, topological connectivity, or, as in the case at hand, ....

Helm, R., and Marriott, K. A Declarative Specification and Semantics for Visual Languages, Journal of Visual Languages and Computing, 2 (1991), pp. 311-331.

....appearances of syntactic units. By syntactic units we mean the visual building blocks required to construct visual programs. The advantages of a declarative style are hiding of low level geometric details from the specifier and the ease of defining spatial relationships among visual objects [9, 2, 1]. VDL addresses three major aspects of visual specification: ffl primitive visual object definitions ffl composite visual object definitions ffl visual layout definition We refer to visual object definitions as vods. Primitive vods serve as a small foundational set of vods, whereas composite ....

....depending on the nature of a language as well as user preference, which makes it impossible to provide built in vods suitable for arbitrary languages. The compose operator is provided specifically for this purpose. The compose operator is similar to the picture specifications defined in [9], where a picture is defined in terms of visual objects and the relationships among them. The relationships are similar to Golin s [6] shape composition operators which define relationships among two objects. These operators are used in shape composition to combine two elements. Our compose ....

[Article contains additional citation context not shown here]

R. Helm and K. Marriott. A declarative specification and semantics for visual languages. Journal of Visual Languages and Computing, 2:311--331, 1991.

....by presenting a parser generator which automates the creation of parsers for picture layout grammars [6] Their C based formalism allows for easy integration of semantic actions and the use of remote symbols makes this method suitable for generating directed parse graphs. Helm and Marriott [8, 9] use a constraint solver such as PROLOG to build graphical parsers. They use the same logic formalism to specify the graphical syntax of a visual language and generate or recognize drawings of this visual language. Wittenburg et al. present the Relational Language System [16] based on unifica5 ....

R. Helm and K. Marriott. A declarative specification and semantics of visual languages. Journal of Visual Languages and Computing, 2(4):311332, December 1991.

.... of attributed grammars (e.g. picture layout grammars [12] positional grammars (e.g. 13] graph grammars (e.g. 14, 15, 16] and algebraic or type theoretic formalisms (e.g. 17, 18] Other work closely related to our approach uses (constraint) logic or relational formalisms (e.g. [19, 20, 21, 22, 23, 24, 25]) for representing spatial relationships. A more detailed review of closely related work on VL theory can be found in [4] GenEd s philosophy of a free form general purpose editor supported by (incremental) visual parsing is in contrast to the following two approaches. Escalante [26] is an ....

R. Helm and K. Marriott, "A Declarative Specification and Semantics for Visual Languages", Journal of Visual Languages and Computing, vol. 2, no. 4, pp. 311--331, Dec. 1991.

....Grammars [4] which are similar to textual context free grammars, except that the right hand side of a production is an unordered collection of symbols rather than a string. Picture Layout Grammars have been widely used to describe the syntax of two dimensional visual languages. Helm and Marriott [8, 9] have introduced a declarative specification technique for visual languages, based on the constraint logic programming language CLP(R) 7] For lack of a better term, we will refer to their framework as to Logic Grammars . The remainder of this paper consists of three parts: first, we will ....

Richard Helm and Kim Marriott, A Declarative Specification and Semantics of Visual Languages, Journal of Visual Languages and Computing2 (1991), pp. 311 -- 331.

....one. All modern languages are changeable in part: functions, procedures, and objects can be defined that extend the namespace, for instance; but they place quite tight restrictions on what can be altered. Attempts to provide general frameworks, e.g. the declarative approach of Helm and Marriott [7,8] or the relational grammars of Crimi et al. 1] make a good start, but they too impose constraints on the kinds of languages that may be dealt with. In part, language inflexibility stems from the need to keep implementations simple and efficient, and so less prone to bugginess. Another factor is ....

R Helm and K Marriott, A Declarative Specification and Semantics for Visual Languages (JVLC 2 4, Academic Press, London) 311-332.

....picture layout grammar [9] and the formalism of Backlund and Hagsand [1, 10] have used attribute grammars for the definition of visual syntax. We define Vodl [20] which is a constraint based declarative picture specification language influenced by the picture specifications of Helm and Marriott [12] and by the work of Wang [23] who defines picture concepts and a framework for picture specification languages. The following section presents the Vodl language, which we use for defining visual tokens (lexicals) Following that, the use of Vodl in visual language specification is discussed in two ....

R. Helm and K. Marriott. A declarative specification and semantics for visual languages. J. Visual Languages and Computing, 2(4):311--332, December 1991.

....the transformation rules to follow the drawn by relations. ffl The graphical part of the transformation rules lacks expressiveness, and there often is a need for additional constraints or actions which need to be defined in a textual manner. 4 RELATED WORK The approach of Helm and Marriott [10, 11] towards graphical parsing is to define the graphical syntax entirely in a logic formalism. They do not split the translation in separate phases. Their parsers are implemented by a constraint solver such as prolog. Wittenburg et al. 16, 17, 18] propose relational unification grammars to specify ....

R. Helm and K. Marriott. A declarative specification and semantics for visual languages. Journal of Visual Languages and Computing, 2(4):311--332, December 1991.

.... grammars [3] relation grammars [4] unification grammars [5, 6, 7] attributed multiset grammars [8] constraint multiset grammars [9] and several types of graph grammars [10] There are also a variety of non grammar like formalisms, including algebraic approaches [11] and logic based approaches [12, 13, 14]. In order to understand the tradeo#s and comparative advantages of these di#erent formalisms, there is a need for a systematic and comprehensive taxonomic hierarchy of visual languages. Such a taxonomy should specify properties of visual languages which allow us to classify them and the position ....

R. Helm and K. Marriott (1991) A declarative specification and semantics for visual languages. Journal of Visual Languages and Computing 2, 311-331.

.... of them are grammar like (such as Web and Array Grammars [15] Shape Grammars [7] Positional Grammars [4] Relational Grammars [6] Unification Grammars [18, 17] Attributed Multiset Grammars [8] Constraint Multiset Grammars [12] and several types of graph grammars [5] but logic based methods [10, 14, 9] and algebraical formalisms [16] are also used. Even when the discussion is restricted to grammar like formalisms, there is such a diversity in the underlying assumptions that a comparison is made di#cult. A systematic, comprehensive hierarchy of VLs based on formal properties an analogue to ....

R. Helm and K. Marriott. A declarative specification and semantics for visual languages. Journal of Visual Languages and Computing, 2, 1991.

.... [3] relational grammars [5] unification grammars [18, 17] attributed multiset grammars [7] constraint multiset grammars [12] and several types of graph grammars [4] There are also a variety of non grammar like formalisms, including algebraic approaches [16] and logic based approaches [10, 14, 9]. In order to understand the tradeo#s and comparative advantages of these di#erent formalisms, there is a need for a systematic and comprehensive taxonomic hierarchy of visual languages. Such a taxonomy should specify properties of visual languages which allow us to classify them and the position ....

R. Helm and K. Marriott. A declarative specification and semantics for visual languages. Journal of Visual Languages and Computing, 2, 1991.

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