ISO 10303-21:2002
(Main)Industrial automation systems and integration — Product data representation and exchange — Part 21: Implementation methods: Clear text encoding of the exchange structure
Industrial automation systems and integration — Product data representation and exchange — Part 21: Implementation methods: Clear text encoding of the exchange structure
Systèmes d'automatisation industrielle et intégration — Représentation et échange de données de produits — Partie 21: Méthodes de mise en application: Encodage en texte clair des fichiers d'échange
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Standards Content (Sample)
INTERNATIONAL ISO
STANDARD 10303-21
Second edition
2002-01-15
Industrial automation systems and
integration — Product data representation
and exchange —
Part 21:
Implementation methods: Clear text
encoding of the exchange structure
Systèmes d'automatisation industrielle et intégration — Représentation et
échange de données de produits —
Partie 21: Méthodes de mise en application: Encodage en texte clair des
fichiers d'échange
Reference number
ISO 10303-21:2002(E)
©
ISO 2002
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ISO 10303-21:2002(E)
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ISO 10303-21:2002(E)
Contents page
1 Scope . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
2 Normative references . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
3 Terms, definitions, and abbreviations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
3.1 Terms defined in ISO 8859-1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
3.2 Terms defined in ISO 10646 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
3.3 Terms defined in ISO 10303-1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
3.4 Terms defined in ISO 10303-11 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
3.5 Other definitions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
3.6 Abbreviations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
4 Exchange structure fundamental concepts and assumptions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
4.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
4.2 Notational and typographical conventions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
4.3 Conformance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
5 Formal definitions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
5.1 Formal notation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
5.2 Basic alphabet definition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
5.3 Exchange structure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
5.4 Definition of tokens . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
5.5 WSN of the exchange structure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
5.6 Token separators . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
6 Tokens . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
6.1 Special tokens . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
6.2 Keywords . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
6.3 Simple data type encodings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
6.3.1 Integer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
6.3.2 Real . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
6.3.3 String . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
6.3.4 Entity instance names . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
6.3.5 Enumeration values . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
6.3.6 Binary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
7 Structured data types . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
8 Header section . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
8.1 Header section entities . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
8.2 Header section schema . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
8.2.1 file_description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
8.2.2 file_name . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
8.2.3 file_schema . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
8.2.4 file_population . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
8.2.5 section_language . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
8.2.6 section_context . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
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ISO 10303-21:2002(E)
8.3 User-defined header section entities . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
9 Data sections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
9.1 Data section entity instances . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
9.2 Data section user-defined entity instances . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
10 Mapping from EXPRESS to the exchange structure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
10.1 Mapping of EXPRESS data types . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
10.1.1 Mapping of EXPRESS simple data types . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
10.1.2 List . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
10.1.3 Array . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
10.1.4 Set . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
10.1.5 Bag . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
10.1.6 Simple defined types . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
10.1.7 Enumeration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32
10.1.8 Select data types . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32
10.2 Mapping of EXPRESS entity data types . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36
10.2.1 Mapping of a simple entity instance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36
10.2.2 Mapping of OPTIONAL explicit attributes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37
10.2.3 Mapping of derived attributes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38
10.2.4 Mapping of attributes whose values are entity instances . . . . . . . . . . . . . . . . . . . . . . 39
10.2.5 Entities defined as subtypes of other entities . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40
10.2.6 Explicit attributes redeclared as DERIVEd . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47
10.2.7 Attributes redeclared as INVERSE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48
10.2.8 Attributes redeclared as explicit attributes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48
10.2.9 Entity local rules . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49
10.2.10 Mapping of INVERSE attributes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49
10.2.11 Encoding of entity type names . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49
10.3 Mapping of the EXPRESS element of SCHEMA . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50
10.4 Mapping of the EXPRESS element of CONSTANT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50
10.5 Mapping of the EXPRESS element of RULE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50
10.6 Remarks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50
11 Printed representation of exchange structures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50
Annex A (normative) File representation on storage media . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51
A.1 Record-oriented transport content . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51
A.1.1 Transport format for magnetic tape media . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51
A.1.2 Other storage media with record-oriented storage . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52
A.2 Line-oriented transport content . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52
A.2.1 Transport format for diskette media . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52
A.2.2 Other media . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53
A.3 Treatment of multi-volume files . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53
Annex B (normative) WSN notational conventions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54
Annex C (normative) Information object registration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56
C.1 Document identification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56
C.2 Schema identification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56
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ISO 10303-21:2002(E)
Annex D (normative) Basic alphabet and graphic character set . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57
Annex E (normative) Protocol Implementation Conformance Statement (PICS) proforma . . . . . . . 58
E.1 Conformance to specified function . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58
Check as many as are appropriate. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58
E.1.1 Entity instance encoding . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58
E.1.2 Short name encoding . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58
E.1.3 String encoding . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58
E.2 Implementation limits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59
Annex F (normative) Multiple EXPRESS schemas in an exchange structure . . . . . . . . . . . . . . . . . . 60
F.1 Reference validity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60
F.1.1 EXPRESS interface specification method . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60
F.1.2 SDAI domain equivalence method . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61
F.2 Determining population of a schema . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62
F.2.1 Section boundary method . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63
F.2.2 Include all compatible method . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 64
F.2.3 Include referenced instance method . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65
Annex G (informative) Guidelines for printing the exchange structure . . . . . . . . . . . . . . . . . . . . . . . 66
G.1 Explicit print control directives . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 66
G.2 Implicit print control directives . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 66
Annex H (informative) Example of a complete exchange structure . . . . . . . . . . . . . . . . . . . . . . . . . 68
H.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68
H.2 Example schema . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68
H.3 Example short names . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69
H.4 Example exchange structure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69
Index . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71
Tables page
Table 1 - WSN defining subsets of the basic alphabet . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Table 2 - WSN of token definitions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Table 3 - WSN of the exchange structure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Table 4 - String control directives . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
Table 5 - Quick reference mapping table . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
Table 6 - Print control directives . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50
Table B.1 - Wirth Syntax Notation (WSN) defined in itself . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55
Table D.1 - Character set used in the exchange structure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57
©ISO 2002 – All rights reserved v
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ISO 10303-21:2002(E)
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national stan-
dards bodies (ISO member bodies). The work of preparing International Standards is normally carried
out through ISO technical committees. Each member body interested in a subject for which a technical
committee has been established has the right to be represented on that committee. International organi-
zations, governmental and non-governmental, in liaison with ISO, also take part in the work. ISO col-
laborates closely with the International Electrotechnical Commission (IEC) on all matters of
electrotechnical standardizations.
International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 3.
Draft International Standards adopted by the technical committees are circulated to the member bodies
for voting. Publication as an International Standard requires approval by at least 75 % of the member
bodies casting a vote.
Attention is drawn to the possibility that some of the elements of this part of ISO 10303 may be the
subject of patent rights. ISO shall not be held responsible for identifying any or all such patent rights.
International Standard ISO 10303-21 was prepared by Technical Committee ISO/TC 184, Industrial
automation systems and integration, Subcommittee SC 4, Industrial data.
This second edition cancels and replaces the first edition (ISO 10303-21:1994), of which it constitutes
a technical revision. It incorporates the corrections published in ISO 10303-21:1994/Cor.1:1996.
This International Standard is organized as a series of parts, each published separately. The structure of
this International Standard is described in ISO 10303-1.
Each part of this International Standard is a member of one of the following series: description meth-
ods, implementation methods, conformance testing methodology and framework, integrated generic
resources, integrated application resources, application protocols, abstract test suites, application inter-
preted constructs, and application modules. This part is a member of the implementation methods
series.
A complete list of parts of ISO 10303 is available from the Internet:
Annexes A, B, C, D, E and F form a normative part of this part of ISO 10303. Annexes G and H are for
information only.
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ISO 10303-21:2002(E)
Introduction
ISO 10303 is an International Standard for the computer-interpretable representation of product infor-
mation and for the exchange of product data. The objective is to provide a neutral mechanism capable
of describing products throughout their life cycle. This mechanism is suitable not only for neutral file
exchange, but also as a basis for implementing and sharing product databases, and as a basis for
archiving.
This part of ISO 10303 specifies a mechanism that allows product data described in the EXPRESS lan-
guage, specified in ISO 10303-11, to be transferred from one computer system to another.
Major subdivisions in this part of ISO 10303 are:
— specification of the exchange structure syntax;
— mapping from an EXPRESS schema onto this syntax.
NOTE The examples of EXPRESS usage in this part of ISO 10303 do not conform to any particular style
rules. Indeed, the examples sometimes use poor style to conserve space or to concentrate on the important points.
The examples are not intended to reflect the content of the information models defined in other parts of this Inter-
national Standard. They are crafted to show particular features of EXPRESS or of the exchange structure. Many
examples are annotated in a way that is not consistent with the syntax rules of this part of ISO 10303. These
annotations are introduced by symbolic arrows, either horizontal '---->', or vertical. These annotations should be
ignored when considering the parse rules. Any similarity between the examples and the normative models speci-
fied in other parts of this International Standard should be ignored. Several mapping examples have been pro-
vided throughout this document. Additional spaces and new lines have been inserted into some of these examples
to aid readability. These spaces and new lines need not appear in an exchange structure.
This edition incorporates the following technical modifications to ISO 10303-21:1994:
— the SCOPE structure (&SCOPE / ENDSCOPE) has been eliminated;
— the exchange structure may now contain multiple data sections;
— the exchange structure header section may now identify the default language for string attributes
of entity instances encoded in a data section;
— the exchange structure header section may now identify information describing contexts within
which the entity instances encoded in a data section are applicable;
— enumeration values may now be encoded using short names if such names are available.
All exchange structures that are encoded according to the previous edition of ISO 10303-21 and that do
not use the SCOPE structure also conform to this edition.
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INTERNATIONAL STANDARD ISO 10303-21:2002(E)
Industrial automation systems and integration —
Product data representation and exchange —
Part 21: Implementation methods:
Clear text encoding of the exchange structure
1 Scope
This part of ISO 10303 specifies an exchange structure format using a clear text encoding of product
data for which the conceptual model is specified in the EXPRESS language (ISO 10303-11). The
exchange format is suitable for the transfer of product data among computer systems.
The mapping from the EXPRESS language to the syntax of the exchange structure is specified. Any
EXPRESS schema can be mapped onto the exchange structure syntax.
2 Normative references
The following normative documents contain provisions which, through reference in this text, constitute
provisions of this part of ISO 10303. For dated references, subsequent amendments to, or revisions of,
any of these publications do not apply. However, parties to agreements based on this part of ISO 10303
are encouraged to investigate the possibility of applying the most recent editions of the normative doc-
uments indicated below. For undated references, the latest edition of the normative document referred
to applies. Members of ISO and IEC maintain registers of currently valid International Standards.
ISO 639-2:1998, Codes for the representation of names of languages — Part 2: Alpha-3 code.
ISO 3788:1990, Information processing — 9-Track, 12,7 mm (0,5 in) wide magnetic tape for informa-
tion interchange using phase encoding at 126 ftpmm (3 200 ftpi) — 63 cpmm (1 600 cpi).
ISO 8601:2000, Data elements and interchange formats — Information interchange — Representation
of dates and times.
ISO/IEC 8824-1:1998, Information technology — Abstract Syntax Notation One (ASN.1): Specification
of basic notation.
ISO/IEC 8859-1:1998, Information technology — 8 bit single-byte coded graphic character sets —
Part 1: Latin alphabet No. 1.
ISO/IEC 8859-2:1999, Information technology — 8 bit single-byte coded graphic character sets —
Part 2: Latin alphabet No. 2.
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ISO 10303-21:2002(E)
ISO/IEC 8859-3:1999, Information technology — 8 bit single-byte coded graphic character sets —
Part 3: Latin alphabet No. 3.
ISO/IEC 8859-4:1998, Information technology — 8 bit single-byte coded graphic character sets —
Part 4: Latin alphabet No. 4.
ISO/IEC 8859-5:1999, Information technology — 8 bit single-byte coded graphic character sets —
Part 5: Latin/Cyrillic alphabet.
ISO/IEC 8859-6:1999, Information technology — 8 bit single-byte coded graphic character sets —
Part 6: Latin/Arabic alphabet.
ISO 8859-7:1987, Information processing — 8 bit single-byte coded graphic character sets — Part 7:
Latin/Greek alphabet.
ISO/IEC 8859-8:1999, Information technology — 8 bit single-byte coded graphic character sets —
Part 8: Latin/Hebrew alphabet.
ISO/IEC 8859-9:1999, Information technology — 8 bit single-byte coded graphic character sets —
Part 9: Latin alphabet No. 5.
ISO 10303-1:1994, Industrial automation systems and integration — Product data representation and
exchange — Part 1: Overview and fundamental principles.
ISO 10303-11:1994, Industrial automation systems and integration — Product data representation and
exchange — Part 11: Description methods: The EXPRESS language reference manual.
ISO/IEC 10646-1:2000, Information Processing — Universal Multiple-Octet Coded Character Set
(UCS) — Part 1: Architecture and Basic Multilingual Plane.
3 Terms, definitions, and abbreviations
3.1 Terms defined in ISO 8859-1
This part of ISO 10303 makes use of the following terms defined in ISO 8859-1.
—byte;
— character;
— graphic character.
3.2 Terms defined in ISO 10646
This part of ISO 10303 makes use of the following term defined in ISO 10646.
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ISO 10303-21:2002(E)
— basic multilingual plane.
3.3 Terms defined in ISO 10303-1
This part of ISO 10303 makes use of the following terms defined in ISO 10303-1.
— application protocol;
— exchange structure.
3.4 Terms defined in ISO 10303-11
This part of ISO 10303 makes use of the following terms defined in ISO 10303-11.
— complex entity instance;
— data type;
—entity;
— partial complex entity instance;
— simple entity instance;
—token.
3.5 Other definitions
For the purposes of this part of ISO 10303, the following definitions apply.
3.5.1
basic alphabet
the set of characters G(02/00) through G(07/14) of ISO 8859-1.
3.5.2
clear text encoding
the encoding of information, using a sequence of codes for characters in the basic alphabet.
3.5.3
control directive
a sequence of characters in the basic alphabet.
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ISO 10303-21:2002(E)
3.5.4
keyword
a special sequence of characters identifying an entity or a defined type in the exchange structure.
3.5.5
section
a collection of data of the same functional category of information.
3.5.6
sequential file
a file that can only be accessed in a sequential manner.
3.5.7
token separator
a sequence of one or more 8-bit bytes that separate any two tokens.
3.6 Abbreviations
For the purposes this part of ISO 10303, the following abbreviations apply:
BMP Basic multilingual plane
WSN Wirth Syntax Notation
4 Exchange structure fundamental concepts and assumptions
4.1 Introduction
The exchange structure is described by an unambiguous, context-free grammar to facilitate parsing by
software. The grammar is expressed in Wirth Syntax Notation that is described in annex B. The form of
product data in the exchange structure is specified using a mapping from the EXPRESS language to the
exchange structure syntax.
4.2 Notational and typographical conventions
Any quotation marks used in this part of ISO 10303 are not part of the text that appears in the exchange
structure but serve to delimit that text. This statement applies to all places in the text where quotation
marks are used. Table 2, Table 3, and Table 4 form an exception to this rule as the quotation marks used
in those tables form part of the WSN rules.
In ISO 8859, each character is assigned an identifying name. When that name is used in this part of
ISO 10303, it is typeset in italics to distinguish if from ordinary text. Thus comma is used to refer to
",", low line refers to "_", and capital letter A refers to "A".
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ISO 10303-21:2002(E)
Within examples in this part of ISO 10303, an annotation is introduced by the sequence ! where
clarification is required.
4.3 Conformance
Two levels of conformance are specified:
— syntactical con
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