Precedence%20Graph%20Grammar%20for%20Hierarchical%20Program%20Diagram

1
Precedence Graph Grammar for Hierarchical
Program Diagram

• ?Takaaki Goto (Toyo University)
• Kenji Ruise (Kirigaoka School for the
  Physically Challenged, University of Tsukuba
  )
• Kensei Tsuchida (Toyo University)
• Takeo Yaku (Nihon University)

2
Contents

1. Introduction
2. Hichart/DXL
3. Preliminaries
4. Graph Grammar for Hichart/DXL
5. Parsing of precedence graph grammar for
   Hichart/DXL
6. Hichart Editor
7. Conclusion

3
1. Introduction

• 1.1 Background
• 1.2 Motivation
• 1.3 Purpose
• 1.4 Results

4
1.1 Background

• Various researches have been done on graph
  grammars and their application
• We have been developing a software development
  environment based on graph grammars
• to formalize of diagrams structure and layout
  information
• to formalize of diagram processing method

5
1.1 Background (cont.)

• The program diagram called Hichart (HIerachical
  flowCHART description language) in this
  environment is treated
• We have already developed bidirectional
  translators that translate
• Pascal, C, or DXL to Hichart
• Hichart to Pascal, C, or DXL

6
1.2 Motivation

• A parser plays a key role in our processing
  system and needs to be efficient as large-scale
  program diagrams are parsed

7
1.3 Purpose

• To adopt a precedence relation of graph grammar
  for Hichart/DXL to parse Hichart diagram
  efficiently

8
1.4 Results

• Adapted a precedence relation of graph grammar
  for Hichart/DXL
• productions 70
• semantic rules 888
• precedence relations 256
• Implemented graphical editor with parser in JAVA

9
2. Hichart/DXL
10
2. Hichart/DXL (cont.)

• Characteristics of Hichart
• Diagram is a tree-flowchart with the same flow
  control lines as a Neumann program flowchart
• The hierarchy of the data structure and the
  control flow are displayed on a plane
  simultaneously

11
2. Hichart/DXL (cont.)

• DXL
• (1) Diagram eXchange Language for tree-structure
  charts, DXL, was specified in the 1997 ISO
• (2) Purpose of DXL is to facilitate the
  interchange of different tree-structure charts
  between CASE tools

12
2. Hichart/DXL (cont.)

• Data exchange between various tree-structure
  diagrams through DXL

(Hitachi)
13
3. Preliminaries

• 3.1 edNCE Graph Grammar
• 3.2 Precedence Graph Grammar

14
3.1 edNCE Graph Grammar
Rozenberg, 1997
15
3.1 edNCE Graph Grammar (cont.)

• Example of production derivation

(a) Host
X
(b) Production
16
3.2 Precedence Graph Grammar

• A graph grammar that is
• confluent
• symmetric
• uniquely invertible
• has no reflexive nonterminals
• no precedence conflicts
• is called precedence graph grammar Kaul, 1986.

17
3.2 Precedence Graph Grammar (cont.)

• derivation specifications
• , where
• is an isomorphic graph of the left hand side
  of a production
• is an isomorphic graph of the right hand side
  of a production
• is an isomorphism

18
3.2 Precedence Graph Grammar (cont.)

• derivation sequences
• precedes if
• The reflexive and transitive closure of this
  relation
• is denoted
• are incomparable if neither
  nor

19
3.2 Precedence Graph Grammar (cont.)

• An ordering of the nodes in Gn is

are the precedence relation between nodes

• The precedence relations between labels

is the set of all
20
4. Graph Grammar for Hichart/DXL

• 4.1 Attribute Graph Grammar for Hichart/DXL
• 4.2 Derivation of GGHD
• 4.3 Precedence Relation for GGHD

21
4.1 Attribute Graph Grammar for Hichart/DXL

• GGHD (Graph Grammar for Hichart/DXL)

GG Type Productions Semantic rules
GGHD Context-free 70 888
22
4.1 Attribute Graph Grammar for Hichart/DXL
(cont.)
Fig. Example of production and semantic rules of
GGHD
23
4.2 Derivation of GGHD

• We substitute (D,C) for a node X in H as
  follows.
• (1) Remove a mother node X , and edges that
  connect with X from host graph H,
• (2) Embed the daughter graph D into H- , and
• (3) Establish edges between the nodes of D and
  the nodes that were connected to the mother node
  in the H of H- using the connection instructions
  of C.

24
4.2 Derivation of GGHD (cont.)
Remove mother node and edges that connect with
profile_module_list
25
4.2 Derivation of GGHD (cont.)
Embed the daughter graph
26
4.2 Derivation of GGHD (cont.)
Establish edges using the connection instructions
27
4.3 Precedence Relation for GGHD

• We adopted a precedence relation of graph grammar
  for Hichart/DXL using Kauls definitions

28
4.3 Precedence Relation for GGHD (cont.)
29
4.3 Precedence Relation for GGHD (cont.)
30
4.3 Precedence Relation for GGHD (cont.)
s1(P1, module_packet, D1, b)
sD(2)s1
sD(3)s1
31
4.3 Precedence Relation for GGHD (cont.)
32
4.3 Precedence Relation for GGHD (cont.)
s2(P3, profile_module_list, D2, b)
sD(4)s2
sD(5)s2
33
4.3 Precedence Relation for GGHD (cont.)
34
4.3 Precedence Relation for GGHD (cont.)
s3(P4, profile, D3, b)
sD(6)s3
sD(7)s3
35
4.3 Precedence Relation for GGHD (cont.)
36
4.3 Precedence Relation for GGHD (cont.)
s4(P5, module_list, D4, b)
sD(8)s4
37
4.3 Precedence Relation for GGHD (cont.)
derivation sequence
The precedence relation between 6 and 7
6 ? 7 ? sD(6) ?D sD(7)
sD(6)s3, sD(7)s3, s3 D s3, 6 7
lab(6, 7) ("profile", , ?, "explanation") ?R
38
4.3 Precedence Relation for GGHD (cont.)

• We defined all the precedence relations between
  labels for grammar GGHD
• We call this grammar the Precedence Graph Grammar
  for Hichart/DXL (PGGHD)
• Property 1
• PGGHD is a precedence graph grammar

39
5. Parsing of Precedence Graph Grammar for
Hichart/DXL

• 5.1 Algorithm for parsing
• 5.2 Example of Parsing

40
5.1 Algorithm for parsing

• uses a stack for storing traversed nodes
• Starts parsing from the root node of an input
  graph
• parsing
• shift as long as possible
• If there is no ascending node, the parser
  searches a production where the right-hand-side
  is isomorphic to the precedence handle.
• reduce the precedence handle to lhs of the
  production

41
5.2 Example of Parsing
An input graph
G
lt
lt
explanation
profile
?
lt
lt
BoxEmpty1
K
An ordered list of G
42
5.2 Example of Parsing (cont.)
G
lt
lt
explanation
profile
?
lt
lt
BoxEmpty1
K
43
5.2 Example of Parsing (cont.)
G
lt
lt
explanation
profile
?
lt
lt
BoxEmpty1
K
44
5.2 Example of Parsing (cont.)
G
lt
lt
explanation
profile
?
lt
lt
BoxEmpty1
K
45
5.2 Example of Parsing (cont.)
G
lt
lt
explanation
profile
?
lt
lt
BoxEmpty1
K
46
5.2 Example of Parsing (cont.)
G
lt
lt
explanation
profile
?
lt
lt
BoxEmpty1
K
47
5.2 Example of Parsing (cont.)
G
lt
lt
explanation
profile
?
lt
lt
BoxEmpty1
K
48
5.2 Example of Parsing (cont.)
G
lt
lt
explanation
profile
?
lt
lt
BoxEmpty1
K
49
5.2 Example of Parsing (cont.)
G
lt

explanation
profile
?
lt
lt
BoxEmpty1
K
50
5.2 Example of Parsing (cont.)
G
lt

explanation
profile
?
lt
lt
BoxEmpty1
K
51
5.2 Example of Parsing (cont.)
G
lt

explanation
profile
?
lt
lt
BoxEmpty1
K
52
5.2 Example of Parsing (cont.)
G
lt
profile
lt
lt
lt
BoxEmpty1
K
53
5.2 Example of Parsing (cont.)
G
lt
profile
lt
lt
lt
BoxEmpty1
K
54
5.2 Example of Parsing (cont.)
G
lt
profile
lt
lt
lt
BoxEmpty1
K
55
5.2 Example of Parsing (cont.)
G
lt
profile
lt
lt
lt
BoxEmpty1
K
56
5.2 Example of Parsing (cont.)
G
lt
profile
lt
lt
lt
BoxEmpty1
K
57
5.2 Example of Parsing (cont.)
G
lt
profile
lt
lt
lt
BoxEmpty1
K
58
5.2 Example of Parsing (cont.)
G
lt
profile
lt
lt
lt
BoxEmpty1
K
59
5.2 Example of Parsing (cont.)
G
lt
profile
lt
lt
lt
BoxEmpty1
K
60
5.2 Example of Parsing (cont.)
G
find_production P14
lt
profile
lt
lt
lt
BoxEmpty1
K
61
5.2 Example of Parsing (cont.)
G
lt
profile
lt
lt

statement_ list
K
62
5.2 Example of Parsing (cont.)
G
lt
profile
lt
lt

statement_ list
K
63
5.2 Example of Parsing (cont.)
G
find_production P11
lt
profile
lt
lt

statement_ list
K
64
5.2 Example of Parsing (cont.)
G
lt
profile
lt
lt
module_ algorithm
K
65
5.2 Example of Parsing (cont.)
G
lt
profile
lt
lt
module_ algorithm
K
66
5.2 Example of Parsing (cont.)
G
find_production P08
lt
profile
lt
lt
module_ algorithm
K
67
5.2 Example of Parsing (cont.)
G
lt
profile
lt

explanation_modue_ algorithm
K
68
5.2 Example of Parsing (cont.)
G
lt
profile
lt

explanation_modue_ algorithm
K
69
5.2 Example of Parsing (cont.)
G
find_production P07
lt
profile
lt

explanation_modue_ algorithm
K
70
5.2 Example of Parsing (cont.)
G
lt
profile
lt
module
K
71
5.2 Example of Parsing (cont.)
G
lt
profile
lt
module
K
72
5.2 Example of Parsing (cont.)
G
lt
profile
lt
find_production P05
module
K
73
5.2 Example of Parsing (cont.)
G
lt
profile

module_ list
K
74
5.2 Example of Parsing (cont.)
G
lt
profile

module_ list
K
75
5.2 Example of Parsing (cont.)
G
lt
profile
find_production P03

module_ list
K
76
5.2 Example of Parsing (cont.)
G

profile_module_ list
K
77
5.2 Example of Parsing (cont.)
G

profile_module_ list
K
78
5.2 Example of Parsing (cont.)
G

find_productionP01
profile_module_ list
K
79
5.2 Example of Parsing (cont.)
G
K
80
5.2 Example of Parsing (cont.)
G
K
finish parsing
81
6. Hichart Editor

• ?Outline?
• Hichart Editor
• Supports non-syntax-directed editing
• has parser
• Java(10,000steps)
• ?features?
• To check the correctness of diagrams
• To draw Hichart diagrams aesthetically
• To generate an SVG file

82
6. Hichart Editor (cont.)

• Input Hichart diagrams
• Output Hichart code with derivation tree
• SVG files with aesthetically drawing

83
DEMO

• Parsing on Hichart Editor
• Generating SVG file on Hichart Editor

84
7. Conclusion

• Summary
• Adapted a precedence relation of graph grammar
  for Hichart/DXL
• productions 70
• semantic rules 888
• precedence relations 256
• Implemented graphical editor with parser in JAVA

85
7. Conclusion (cont.)

• Our graph grammar based method would be able to
  apply to other visual programming systems that
  treat tree-like graphs

86
7. Conclusion (cont.)

• Future work
• To apply our method of graph grammar to
  Object-Oriented Language