E.J. Golin. A Method for the Specification and Parsing of Visual Languages. PhD thesis, Brown University, 1991.  Home/Search   Document Not in Database   Summary   Related Articles   Check

....parsing algorithms proposed so far are either unable to recognize interesting languages of graphs, 4 Author for correspondence. or tend to be inefficient when applied to graphs with a large number of nodes and edges. Another problem is that nearly all known graph grammar parsing algorithms [2, 3, 4, 5, 6, 7] deal only with contextfree productions. A context free grammar requires that only a single non terminal is allowed on the left hand side of a production [8] A context sensitive graph grammar, on the other hand, allows left hand and right hand graphs of a production to have an arbitrary number of ....

....complicated mechanism is needed to establish relationships between the substitute of a redex and its adjacent elements. There are three approaches to embedding a graph into a host graph [9] FIGURE 6. Examples of the R application. Implicit embedding. Formalisms such as picture layout grammars [4] and constraint multiset grammars [13] do not distinguish between vertices and edges. Relationships are implicitly defined as constraints over their attribute values. Attribute assignments within productions have the implicit side effect that creates new relationships to unknown context elements. ....

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Golin, E. J. (1991) A Method for the Specification and Parsing of Visual Languages. PhD Thesis, Brown University.

....Consequently, most graph grammar parsing algorithms proposed so far are either unable to recognize interesting languages of graphs or tend to be inefficient when applied to graphs with a large number of nodes and edges. Another problem is that nearly all known graph grammar parsing algorithms [7][8] 17] deal only with context free productions. A context free grammar requires that only a single non terminal is allowed on the left hand side of a production [19] A context sensitive graph grammar, on the other hand, allows left hand and right hand graphs of a production to have arbitrary ....

E.J. Golin, A method for the specification and parsing of visual languages, PhD Thesis, Brown University, May 1991.

....and two selected characters) Visual sentence denoting replacement of a substring in a string. 6 the fact that digital pictures are composed of pixels. These grammars discover the structure of visual sentence by composing individual pixels into recognizable visual elements (lines, arks, etc. [Golin 1990]. This approach is useful when an iconic system needs to be able to recognize icons with a certain level of error tolerance (e.g. handwritten digits) Precedence grammars This spatial parsing grammar can be used for two dimensional mathematical expression analysis and printed page analysis. ....

Golin, E. J. A method for the specification and parsing of visual languages. PhD dissertation, Brown University, 1990. 28

....visual programming tools. Although visual languages are used wide spread, there is still a standard visual formalism as the Backus Naur Forms missing to define their syntax and semantics. All the currently used grammars for syntax definition of visual languages, such as picture layout grammars [45,46], or constraint multiset grammars [66] use textual instead of visual notations, i.e. multi dimensional representations have to be coded into one dimensional strings. Using graph grammars instead we have a much more natural and itself visual formalism for this purpose. Visual sentences consisting ....

....nonempty relational structure no yes explicitly def. vertex ordering by relations exponential relational Ferrucci et al. 39] one nonterminal rel. structure without nonterminal neighbours no yes (bounded degree, connected structure) exponential (polynomial) Golin [45] one nonterminal one or two (non) terminals one nonterminal implicit finite set of possible attribute values polynomial Picture Costagliola et al. 27] one nonterminal positional sentential form no implicit or fixed set of connection points LR condition linear ....

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E. Golin. A method for the specification and parsing of visual languages. PhD thesis, Brown University, 1991.

....For example, recall the production for transitions given above; here the attributes of the LHS symbol TR are directly copied from the RHS symbols R and S. So CCMGs are not only of theoretical value, but can directly be used for real specifications. Indeed the Picture Layout Grammars of Golin [19] are copy restricted. In the light of copy restriction, we can revisit the mappings of other formalisms into the full CMG formalism that were discussed in Section 2.1. The mapping of PGs obviously already generates copyrestricted CMGs, since no attribute computations are used. For ARGs our ....

E.J. Golin (1991) A method for the specification and parsing of visual languages. PhD thesis, Brown University.

....13 Let G be one of CCMG 3 or CCMG 2 . The complexity of the membership problem for a fixed grammar G # G is NP complete. The complexity of the membership problem for G is PSPACE complete. This follows from the following four lemmas. The first follows from the encoding of 3 SAT in Golin [8]. Lemma 4 For some G # CCMG 3 the membership problem is NP hard. Lemma 5 For any fixed G # CCMG 2 the membership problem is in NP. Proof The NP algorithm is to guess a derivation D for S which does not have any repeated sentences and with each stage identifies the tokens reduced at the ....

E.J. Golin. A Method for the Specification and Parsing of Visual Languages. PhD thesis, Brown University, 1991.

...., circle, sector , straightLine, arrow , and doubleArrow . Such a limited set is sufficient for the kinds of displays of the database that we consider (e.g. graphs, bar charts, pie charts) Sets of visual objects that are considered in related work are comparable to the one we consider (e.g. [Gol91, Wyk82]) or more restricted (e.g. Mac86] 0 (v) ss ee ww nn (i) nn ss ee ww (iii) nn ss ee ww . iv) ii) X Y procedure X draw name inModule contains secondObject 0 0 0 0 firstObject contains secondObject 0 0 0 0 firstObject V O1 V Ok lx solid by rx ty boundary box solid lx ....

Eric J. Golin. A Method for the Specification and Parsing of Visual Languages. Technical Report CS-90-19, Brown University, May 1991.

....to research into generation of language specific environments based on formal language specifications. The specification of languages consists of specifications of syntax, semantics and other language features. Work in programming environment generation includes [17, 13] for textual languages, and [6, 1, 7, 14, 21] for visual languages. For whatever reason graphics may be used, there is a need for languages which specify graphical constructs. Such languages describe pictures for applications such as document preparation, visualization, pretty printing, visual languages, etc. Some of the picture definition ....

E. J. Golin. A method for the specification and parsing of visual languages. PhD thesis, Brown University, 1990.

....display, but are not specification equivalent. 4 Conclusions We have presented a new constraint based visual language, the U term language, to specify the display of data. This language is declarative and visual. Other languages which are also constraint based, such as IDEAL [Wyk82] Kam89] and [Gol91], are textual. Of these, only IDEAL addresses the display of sectors like the ones that are used in pie charts (called wedges) In ways, our work is closer to (and also drew from) ThingLab [Bor81] in that the user can define visual classes by example, and the language is constraint based and ....

....Abstract U term. Expressive power of doodle as a picture generator. The example of Figure 1(i) is relatively simple: for instance we have no recursion in the rules. With recursion it seems that doodle would have at least the same expressive power to generate pictures as visual multiset grammars [Gol91]. The precise comparison of the expressive power of both approaches is another subject for future research. Acknowledgements Thanks to Theo Norvell for fruitful discussions that led to the definition of the visual constraint objects and to the refinement of the abstract syntax. ....

Eric J. Golin. A Method for the Specification and Parsing of Visual Languages. Technical Report CS-90-19, Brown University, May 1991.

....editing mainly requires two kinds of specification: visual appearances and editing behavior. Thus, two specification languages, VODL (Visual Object Definition Language) which is used in specifying the visual syntax and EDL (Editor Definition Lan 1 Visual parsing is an active research area [14, 6], however we feel that the results are not yet satisfactory enough for us to depend on them. Editor gen. Visual Specifier SVE user Graphical platform Formal specification environment L L V Phase 1 Phase 2 Phase 3 VED L Figure 1: The overall view of a structured visual editor generation. L ....

....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 operator differs somewhat from Golin s shape compositions in that we define composition to be over an arbitrary number of elements ....

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E. J. Golin. A method for the specification and parsing of visual languages. PhD thesis, Brown University, 1990.

....visual programming tools. Although visual languages are used wide spread, there is still a standard visual formalism as the Backus Naur Forms missing to define their syntax and semantics. All the currently used grammars for syntax definition of visual languages, such as picture layout grammars [4,5], or constraint multiset grammars [6] use textual instead of visual notations, i.e. multi dimensional representations have to be coded into one dimensional strings. Using graph grammars instead we have a much more natural and itself visual formalism for this purpose. Visual sentences consisting ....

....reference point is given by a variable, i.e. it can be defined by any position. The sizes (Width, Height) are defined by variables, too. They are instantiated by concrete values when a production is applied. The size of the box depends on the size and relative positions of its parameters. box([4,1], 2,3] rect( 0,0] 2,1] 0, white) rect( 0,1] 2,1] 0, white) rect( 0,2] 2,1] 0, white) layout(Class) 1 2 4 6 5 3 1 2 3 4 7 r1: rect( 1,4] 2,1] 0, white) r2: rect( 1,3] 2,1] 0, white) r3: rect( 1,2] 2,1] 0, white) Figure 1.12: Graphical expression (type) for a class. On ....

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E. Golin. A method for the specification and parsing of visual languages. PhD thesis, Brown University, 1991.

....requires touch typing ) One way to parse a visual language is to allow the user to produce a picture using a standard visual editor. The picture and a description of the visual language are then fed into a spatial parser, producing a structure analogous to a parse tree for textual languages [Golin 1990]. This was the approach taken by the Visual Programmer s Workbench [Rubin 1990] an attempt to develop a set of tools for visual languages analogous to the editors, lexical analyzers, parsers, compilers, and debuggers for textbased programming languages. Since visual languages typically express ....

Eric J. Golin. A Method for the Specification and Parsing of Visual Languages. Ph.D. dissertation, Department of Computer Science, Brown University, Providence, R.I. 1990.

....with segmentation, vectorization and feature extraction. Constraint based grammars such as we use are recognized as useful for expressing relations among graphical objects in 2 dimensional space [3] Others include Relation Grammars [14, 15] Graphical F PATR Grammars [16] Picture Layout Grammars [17 19] and Constraint Set Grammars [20] Despite the theoretical foundation that these approaches provide, it is not clear how to use them to achieve efficient parsing for particular application domains. Most are based on exhaustive bottom up analysis and as a result, they are inefficient, especially in ....

....especially in cases of many local matches that are not part of a complete solution. Wittenburg has developed a bottom up tabular parsing algorithm that has successfully applied in the some interactive domains: flowchart and mathematical expressions interpretation [16] and document design [21] In [19] an algorithm for spatial parsing is presented that is based on the CYK parsing algorithm. All of these approaches appear to have difficulty parsing diagrams of realistic size. RG 1 grammars were introduced [22] in order to make parsing tractable, but the grammars were then not expressive enough ....

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Golin, E.J., A Method for the Specification and Parsing of Visual Languages. 1991, Brown University:

....visual editing mainly requires two kinds of specification: visual appearances and editing behavior. Thus, two specification languages, VDL (Visual Definition Language) and EDL (Editor Definition Language) are developed to address these needs. 1 Visual parsing is an active research area [15, 4, 6], however we feel that the results are not yet satisfactory enough for us to depend on them. Visual for L Syntax Formal spec. of L Editor gen. Visual Specifier Formal specification environment Graphical platform Visual editor user Phase 1 Phase 2 Phase 3 Structured Visual for L Editor des. ....

....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 operator differs somewhat from Golin s shape compositions in that we define composition to be over an arbitrary number of elements ....

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E. J. Golin. A method for the specification and parsing of visual languages. PhD thesis, Brown University, 1990.

....[3] Positional Grammars [2] Fringe Relational Grammars [11] and Picture Layout Grammars. Picture Layout Grammars [6, 5] are one of the most flexible of these grammars. They are based on Attributed Mul Supported by the National Science Foundation under grant CCR9007195 tiset 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 ....

Eric J. Golin. A Method for the Specification and Parsing of Visual Languages, Ph. D. thesis, Brown University, 1990.

....modeling the structure of diagrams. Under a such scheme, the analysis of a diagram consist of identifying the exact correspondence between the diagram and the underlying grammar. The most noticeable models are the Relation Grammars [8, 9] Graphical F PATR Grammars [10] Picture Layout Grammars [11 13], and Constraint Set Grammars [14] While they are capable of describing a variety of domains, these systems do not appear to be efficient enough to parse diagrams of any real complexity (e.g. N=100 to 200 elements) as they are more or less based on 4 exhaustive techniques used to parse ....

Golin, E.J. (1991). A Method for the Specification and Parsing of Visual Languages, PH.D Dissertation, Brown University.

....all graph grammar parsing algorithms suggested up to now are either unable to recognize interesting languages of graphs, or tend to be hopelessly inefficient when applied to graphs with more than a few dozen nodes and edges 1 . Even worse, all currently known graph grammar parsing algorithms [10, 16, 12, 21, 3, 22, 7] deal with context free productions only (where the left hand side is a single non terminal node) This might be sufficient from the theoretical point of view 2 . But in practice it would be quite useful to allow arbitrary graphs in the left hand side of a production, which might even share a ....

....this section is too long already. 6 Related work Up to now, only a handful of proposals are published on how to parse graph like data structures generated by graph grammars [10, 16, 12, 21] or related formalisms like plex grammars [3] relational fringe grammars [22] or picture layout grammars [7]. These approaches fall into two classes with respect to the overall organization of the parsing algorithm. On one side, we have Earley style [5] approaches [3, 22] which start at a single node of the given input graph and extend the already examined part of the graph step by step. Each extension ....

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E.J. Golin. A method for the specification and parsing of visual languages. PhD thesis, Brown University, May 1991.

....evaluating them. Accordingly, we have seen 1 There was much discussion about this during VL 94 (10th VL Symposium) where panels reflected and projected on the success of visual languages. considerable work in the area of visual programming environments (VPEs) 7] as well as in VPE generators [8, 19, 1, 10, 20, 4]. This paper discusses visual language specification and VPE generation based on specifications. Section 2 gives a brief discussion of programming environment generation. Section 3 discusses the picture specification language, Vodl, which is used in defining lexical syntax. Section 4 describes an ....

....generation of programming environments is based on the specification of languages, which consists of the syntax, semantics and other language features. For textual languages, several programming environment generators exist [18, 14] For visual languages some of the work on VPE generation includes [8, 19, 1, 10] who use attribute grammars, 16] who defines an object oriented framework, and [20] who uses algebraic specifications for specifying languages. This work is an attempt to extend ASF SDF (an algebraic specification formalism [2] for visual language specification. The success of algebraic ....

E. J. Golin. A method for the specification and parsing of visual languages. PhD thesis, Brown University, 1990.

....Wittenburg et al. 16, 17, 18] propose relational unification grammars to specify the parsing of pictorial objects and their spatial relations. They implement the parsers defined by these grammars with a chart based relational parsing algorithm which has been developed by them also. Golin et al. [5, 6, 7, 8] present a compiler generator for visual languages which is based on the notion of picture layout grammars. In such a grammar a syntax rule is limited to a single spatial relation which connects two symbols. This generally leads to a large number of nonterminals and syntax rules. Symbols may be ....

E. J. Golin. A method for the specification and parsing of visual languages. PhD thesis, Brown University, May 1991.

....sides of productions with context elements, in order to be able to create edges between new vertices and preserved vertices in the rewritten host graph. This is just one popular solution of the embedding problem. The others are: ffl Implicit Embedding: formalisms like picture layout grammars [12, 13] or constraint multiset grammars [5, 4] do not distinguish between vertex and relationship objects. All needed relationships between objects are implicitly defined as constraints over their attribute values. Therefore, attribute assignments within productions have the implicit side effect to ....

....[5] does not check whether the resulting derivation is consistent. This means that a syntax specification has to be made deterministic by additional not exists constraints which prevent any possible overlap between the right hand sides of productions. The picture layout grammar approach of Golin [12, 13] allows for terminal context elements, but has a main focus on productions with one nonterminal on the left hand side and at most two (non )terminals on the right hand side, with predefined spatial relationships between them. A definition of a grammar which generates our language of connected ER ....

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E. Golin. A method for the specification and parsing of visual languages. PhD thesis, Brown University, 1991.

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E.J. Golin. A Method for the Specification and Parsing of Visual Languages. PhD thesis, Brown University, 1991.

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Golin, E. J. A method for the specification and parsing of visual languages. PhD dissertation, Brown University, 1990.

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