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1 Introduction
1.1 Terminology
2 Definitions
2.1 SQName
2.2 Unit string representation
A References
B Intellectual property status (non-normative)
C Document History (non-normative)
D Errata Corrections incorporated in this document
1 Examples of standard string representation of units
The XBRL Open Information Model provides a syntax-independent definition of the content of an XBRL report. A number of alternative syntaxes are defined as concrete representations of the model. In order to achieve consistency between these representations, this document provides a number of definitions which may be used across these different formats.
The key words MUST, MUST NOT, REQUIRED, SHALL, SHALL NOT, SHOULD, SHOULD NOT, RECOMMENDED, MAY, and OPTIONAL, in this specification, are to be interpreted as described in [IETF RFC 2119].
The keywords expanded name, NCName and QName are to be interpreted as described in the XML Names specification [XML Names].
The keywords Unit Core Aspect are to be interpreted as described in the Open Information Model [OIM].
The Open Information Model makes extensive use of expanded names ([XML Names]) to provide globally unique identifiers. These are a namespace URI/localname pair. In order to reduce size and improve readability, it is convenient to use a QName-like mechanism for representing these (and some other) values, where the globally unique namespace-URI is replaced with a compact, document-scoped prefix. The mechanism used is referred to as an SQName ("Simplified QName").
An SQName is a compact, colon-separated represention of a URI/value pair, where a short, document-scoped, prefix is used to represent the URI.
An SQName has the following format:
prefix:localname
The prefix MUST be a valid NCName and MUST correspond to a key in the prefix map, and the namespace URI for identifier is taken from the corresponding value in the map.
Unlike QNames, the localname may be any string, including those containing the colon (":") character; the prefix and localname in an SQName are separated by the first colon character. Where an SQName is used to represent an expanded name, the localname will be a valid NCName.
A prefix map is a set of prefix/URI pairs that is used to resolve the prefix component of an SQName to a URI. The location and format of a prefix map is defined by the representation in which it is used, but it MUST conform to the following constraints:
SQNames are similar to QNames appearing within XML documents, but have the following differences, intended to make consumption simpler:
The Unit Core Aspect defines units in terms of the combination of QNames by defining a list of numerators and a list of denominators. Reflecting this in concrete representations can be somewhat cumbersome, particularly as analysis the structure of units is expected to be a relatively uncommon operation compared to simply comparing units for equivalence, or rendering them to a user.
This section defines a standardised string representation for units, allowing units to be captured using a single, simple string value. This has the property that, provided that a consistent set of namespace prefixes are used, a given unit will have the single representation meaning that equivalence of units can be determined by a simple string comparison.
This representation is obtained as follows:
Whitespace is not permitted anywhere in the string representation, and the use of SQNames ensures that a 1:1 mapping between prefixes and namespaces is available thus ensuring that equivalent units appearing within the same document are represented with the same string.
Lexicograhic order means ordered based on comparison of Unicode code point values of each character.
The following list show a set of valid unit string representations.
iso4217:EUR
iso4217:EUR/xbrli:shares
utr:m*utr:m
utr:kg/(utr:m*utr:m)
(utr:m*utr:m*utr:m)/utr:S
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Date | Author | Details |
---|---|---|
14 December 2016 | Paul Warren |
Candidate Recommendation. The contents of this specification were previously included in Public Working Drafts of the xBRL-JSON and OIM specifications. |
This appendix contains a list of the errata that have been incorporated into this document. This represents all those errata corrections that have been approved by the XBRL International Specification Maintenance Working Group (SWG) up to and including 14 December 2016. Hyperlinks to relevant e-mail threads may only be followed by those who have access to the relevant mailing lists. Access to internal XBRL mailing lists is restricted to members of XBRL International Inc.
No errata have been incorporated into this document.