ISO/IEC 14568:1997
(Main)Information technology — DXL: Diagram eXchange Language for tree-structured charts
Information technology — DXL: Diagram eXchange Language for tree-structured charts
Technologies de l'information — DXL: Langage pour échange de diagramme pour cartes avec arborescence
General Information
Standards Content (Sample)
ISO/IEC
INTERNATIONAL
14568
STANDARD
First edition
1997-05-I 5
Information technology - DXL: Diagram
exchange Language for tree-structured
charts
- DXL: Langage pour @change de
Technologies de I’informa tion
diagramme pour cartes avec arborescence
Reference number
ISO/l EC 14568: 1997(E)
---------------------- Page: 1 ----------------------
ISO/IEC 14568: 1997(E)
Contents
1
1 Scope . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .~.~.
1
2 Normative references . . . . . . . . . . . . . . . . . . . . . .~.~.~.~.~.
2
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3 Definition and acronym
2
4 Notation of DXL syntax . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .*.
2
5 Definition of DXL . . . . . . . . . . . . . . . . . . .~.‘.
Annexes
8
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
A Examples of DXL description
11
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
B Correspondences between DXL syntax and program constructs of ISOAEC 863 1
13
C Position of DXL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
0 ISO/IEC 1997
All rights reserved. IJnless otherwise specified, no part of this publication may be reproduced or utilized in any form or
by any means, electronic or mechanical, including photocopying and microfilm, without permission in writing from the
publisher.
ISO/IEC Copyright Office l Case postale 56 l @H-l21 1 Geneve 20 l Switzerland
Printed in Switzerland
ii
---------------------- Page: 2 ----------------------
0 ISO/IEC ISO/IEC 14568: 1997(E)
Foreword
IS0 (the International Organization for Standardization) and IEC (the International Electrotechnical
Commission) form the specialized system for worldwide standardization. National bodies that are members
of IS0 or IEC participate in the development of International Standards through technical committees
established by the respective organizations to deal with particular fields of technical activity. IS0 and IEC
technical committees collaborate in fields of mutual interest. Other international organizations, governmental
and non-governmental, in liaison with IS0 and IEC, also take part in the work.
In the field of information technology, IS0 and IEC have established a joint technical committee, ISO/IEC
JTC 1. Draft International Standards adopted by the joint technical committee are circulated to national
bodies for voting. Publication as an International Standard requires approval by at least 75 % of the national
bodies casting a vote.
International Standard ISO/IEC 14568 was prepared by Joint Technical Committee ISO/IEC JTC 1,
Information technology, Subcommittee SC 7, Software engineering.
Annexes A to C of this International Standard are for information only.
. . .
111
---------------------- Page: 3 ----------------------
0 ISO/IEC
ISO/IEC 14568:1997(E)
Introduction
This International Standard defines DXL (Diagram exchange Language for tree-structured charts). The
purpose of DXL is to facilitate the interchange of different tree-structured charts among CASE tools.
Tree-structured charts and their supporting CASE tools are widely used in algorithm design of software, but
their notation is not standardized yet, although Program Constructs were standardized in ISO/IEC 863 1.
Having different kinds of notation for tree-structured charts causes trouble in large-scale software
development: developers are forced to understand unfamiliar notation and sometimes make mistakes in
reviewing a design document if the notation is not uniform.
However, it would take a long time to establish and popularize the standard notation, because it would be
time consuming and expensive to re-educate designers and modify existing CASE tools to be conformed to
the standard. Therefore, it is better to standardize a data exchange language among CASE tools, because:
1. developers can easily read charts in a familiar notation if unfamiliar notation can be converted through the
data exchange language; and
2. existing CASE data can also be reused if it can be converted through the data exchange language.
iv
---------------------- Page: 4 ----------------------
INTERNATIONAL STANDARD 0 ISO/IEC ISO/IEC 14568: 1997(E)
DXL: Diagram exchange Language
Information technology -
for tree-structured charts
1 Scope
This International Standard specifies the semantics and syntax of DXL. DXL is a language for exchanging
tree-structured charts among CASE tools.
DXL is applicable to:
1. exchanging ISO/IEC 863 1 compliant tree-structured charts (examples of which are shown in annex A
(informative) of ISO/IEC 863 1);
2. exchanging program flowcharts defined in ISO/IEC 5807 if they are well-structured and don’t have data
defined in ISOIIEC 5807; and
3. describing procedure oriented algorithms.
This International Standard does not specify:
1. graphical information about a chart, such as the shape, size, and location of symbols;
2. configuration information of a chart, such as its version, author, and file name; or
3. information about the data used in the algorithm described by DXL, such as its structure, reading and
writing, and declaration.
2 Normative references
The following standards contain provisions which, through reference in this text, constitute provisions of this
International Standard. At the time of publication, the editions indicated were valid. All standards are subject
to revision, and parties to agreements based on this International Standard are encouraged to investigate the
possibility of applying the most recent editions of the standards indicated below. Members of IEC and IS0
maintain registers of currently valid International Standards.
- ISO 7-bit coded character set for information interchange.
ISOIIEC 646: 199 1, Information technology
Character code structure and extension techniques.
ISO/IEC 2022: 1994, Information technology -
ISOIIEC 4873: 199 1, Information technology - IS0 g-bit code for information interchange - Structure and
rules for implementation.
IS0 5807: 1985, Information processing - Documentation symbols and conventions for data, program and
system flowcharts, program network charts and system resources charts.
ISO/IEC 863 1: 1989, Information technology - Program constructs and conventions for their represen-
tation.
IS0 8859-l : 1987’, Information processing - g-bit single-byte coded graphic character sets - Part I: Latin
alphabet No. I.
ISO/IEC 10646- 1: 1993, Information technology - Universal Multiple-Octet Coded Character Set (KS) -
Part I: Architecture and Basic Multilingual Plane.
’ Currently under revision.
---------------------- Page: 5 ----------------------
0 ISO/IEC
ISO/IEC 14568: 1997(E)
3 Definition and acronym
For the purposes of this International Standard, the following definition and acronym apply.
3.1 Definition
3.1.1 tree-structured chart: A chart depicting program constructs defined in ISO/IEC 863 1 and having the
structure of a tree.
3.2 Acronym
3.2.1 CASE: Computer Aided Software Engineering
4 Notation of DXL syntax
The metalanguage used in this International Standard to specify the syntax of the constructs is based on
Backus-Naur Form. The notation has been modified from the original to permit more convenient description.
Table 1 lists the meanings of the various meta-symbols.
Table 1: Metalanguage Symbols
Meaning
Metasymbol
. .-
-
is defined to be
. .
-1 alternatively I
1 0 or 1 instance of A
I
1 0 or more instances of A I
1 terminal symbol XYZ of level 0
I
I “XYZ” 1 terminal symbol XYZ of level 1 I
I 1 nonterminal symbol XYZ of level 0
I
I <> 1 nonterminal symbol XYZ of level 1 I
There are two levels of compliance, level 0 and level 1. Level 0 includes syntactic elements compliant only to
Program Constructs of ISOIIEC 863 1. Level 1 includes level 0 and syntactic elements corresponding to
subdivided elements of Program &lonstructs.
5 Definition of DXL
5.1 Lexical elements
: := 1
- - - - -
: : = { }
: := 1 1 1 < specification>
I I I <>
-
::= ‘;’ I ‘:’ I
:= ‘M Packet’ I ‘End M Packet’
I ‘Profile’ I ‘End Profile’
I ‘Identification’ r ‘End Identification’
I ‘Identifier’ I ‘is’ -
I ‘Module Algorithm’ I ‘End Module Algorithm’
“null” I %ail” I “gito”
I ‘imperative’ I
I “abstract” I ‘begin’ I ‘end’ I ‘parallel’ ) ‘endparallel’
I ‘loop’ I ‘end loop’ I ‘condition’ I “while” I “until” I “for”
I ‘if I ‘then’ r’end-if I ‘exclusive-select’ ( ‘else-if I ‘else’
I ‘end exclusive-select’ I ‘case’ I ‘when’
I ‘inclusive select’ I “end-inclusive-select’
I ‘terminate; I ‘system’ I ‘module’ I ‘block’
2
---------------------- Page: 6 ----------------------
ISO/IEC 14568: 1997(E)
0 ISO/IEC
::= ‘<’ ‘>’
::= ‘ [’ { 1 } ‘I’ [ <> ]
-
::= ‘ [’ { I
-
::= ‘--’ { I }
<> ::= ‘ ‘% { ” { I “Oh} ”
-
A is one of the graphical characters defined in ISO/IEC 646, ISO/IEC 2022,
ISO/IEC 4873 andjSO/IEC 8859-l. A is another standard character such as
ISO/IEC 10646-l. are control ch&actek defined in ISO/IEC 646. is LF defined in
ISO/IEC 646. is HT defined in ISO/IEC 646.
A is separated from other lexical elements by delimiters (‘<‘, ‘>‘, ‘[‘,‘I’, ‘%[‘, ‘I%‘, ‘;‘) or by
one or more spaces.
identifies a part of or a position in a module.
in describes a specification of a process or a condition.
The description rule of <> and is implementation-dependent.
-
Delimiters can be inserted into only by putting an escape character ‘\’ immediately in front of them.
5.2 Module Packet
Module Packet is a unit for exchanging tree-structured charts among CASE tools.
::= ‘M-Packet’
{
}
‘End M Packet’ ‘;’
- -
5.3 Profile Paragraph
Profile Paragraph supplements information used to analyze and
-
.
-
::= ‘Profile’
[ ]
‘End Profile’ ‘;’
-
should include:
1. the code set used in and ;
2. the maximum string length of, , <>,
-
and ;
3. the type of tree-structured chart; and
4. information about the level of compliance described in clause 4.
5.4 Module Identification Paragraph
Module Identification Paragraph provides the name and the overview of the
algorithmparagragh>
-
following immediately afterwards.
---------------------- Page: 7 ----------------------
ISO/IEC 14568:1997(E) 0 ISO/IEC
-
0e l *= ‘Identification’
‘Identifier’ ‘is’ ‘;’
[ ]
‘End Identification’ ‘;’
-
shall be unique within Module Packet.
should include:
1. the module specification, such as function, usage, and interface;
2. the module type, such as system, subprogram, task, process, procedure, subroutine, or function; and
3. the programming language for implementing the module.
5.5 Module Algorithm Paragraph
Each Module Algorithm Paragraph describes an algorithm of a tree-structured chart for each module.
::= ‘Module Algorithm’
-
‘End Module Algorithm’ ‘;’
- -
5.5.1 Statement
: := ( { <
Questions, Comments and Discussion
Ask us and Technical Secretary will try to provide an answer. You can facilitate discussion about the standard in here.