Unit Filters 1.0

Recommendation 22 June 2009

Copyright ©2009 XBRL International Inc., All Rights Reserved.

This version:
<http://www.xbrl.org/Specification/unitFilters/REC-2009-06-22/unitFilters-REC-2009-06-22.html>
Editors:
Phillip Engel, Morgan Stanley <phillip.engel@morganstanley.com>
Herm Fischer, UBMatrix / Mark V Systems <fischer@markv.com>
Victor Morilla, Banco de España <victor.morilla@bde.es>
Jim Richards, JDR & Associates <jdrassoc@iinet.net.au>
Geoff Shuetrim, Galexy <geoff@galexy.net>
David vun Kannon, PricewaterhouseCoopers LLP <david.k.vunkannon@us.pwc.com>
Hugh Wallis, XBRL International <hughwallis@xbrl.org>
Contributors:
Cliff Binstock, Coyote Reporting <cliff.binstock@coyotereporting.com>
Paul Bull, Morgan Stanley <paul.bull@morganstanley.com>
Masatomo Goto, Fujitsu <mg@jp.fujitsu.com>
Walter Hamscher, Standard Advantage / Consultant to PricewaterhouseCoopers LLP <walter@hamscher.com>
Ignacio Hernández-Ros, Reporting Estandar S.L. <ignacio@hernandez-ros.com>
Roland Hommes, Rhocon / Consultant to Netherlands Tax and Customs Administration <roland@rhocon.nl>
Andy Harris, UBMatrix <andy.harris@ubmatrix.com>
Takahide Muramoto, Fujitsu <taka.muramoto@jp.fujitsu.com>
Hitoshi Okumura, Fujitsu <okmr@jp.fujitsu.com>
Pablo Navarro Salvador, Atos Origin sae <pablo.navarro@atosorigin.com>
Michele Romanelli, Banca d'Italia <michele.romanelli@bancaditalia.it>
Nathan Summers, CompSci Resources <nathan.summers@compsciresources.com>
Masaru Uchida, Fujitsu <m-uchida@jp.fujitsu.com>

Status

Circulation of this Recommendation is unrestricted. This document is normative. Recipients are invited to submit comments to formula-feedback@xbrl.org, and to submit notification of any relevant patent rights of which they are aware and provide supporting documentation.

Abstract

This specification defines syntax for filters that can condition on units of measurement when selecting facts from XBRL instances.

Table of Contents

1 Introduction
1.1 Background
1.2 Relationship to other work
1.3 Language independence
1.4 Terminology
1.5 Document conventions (non-normative)
1.6 Namespaces and namespace prefixes
1.7 XPath usage
2 Syntax
2.1 Single-measure unit filter
2.2 General unit filter

Appendices

A Normative schema
B References
C Intellectual property status (non-normative)
D Acknowledgements (non-normative)
E Document history (non-normative)
F Errata corrections in this document

Table

1 Namespaces and namespace prefixes

Examples

1 Single-measure unit filters
2 General unit filters

Definitions

general unit filter
single-measure unit filter


1 Introduction

This specification is an extension to [VARIABLES]. It defines XML syntax [XML] for filters that can condition on units of measurement when selecting facts from XBRL instances.

All of the filters defined in this specification can cover the unit aspect.

1.1 Background

This specification is a member of a suite of similar specifications that define specific types of criteria that can be used to select facts from XBRL instances. It enhances the fact selection capabilities of the XBRL Variables Specification [VARIABLES].

1.2 Relationship to other work

This specification depends upon the XBRL Specification [XBRL 2.1], and the XBRL Variables Specification [VARIABLES]. In the event of any conflicts between this specification and the specifications upon which it depends, this specification does not prevail.

1.3 Language independence

The official language of XBRL International's own work products is English and the preferred spelling convention is UK English.

1.4 Terminology

This specification is consistent with the definitions of any of the terms defined in specifications that it depends on.

1.5 Document conventions (non-normative)

Documentation conventions follow those set out in the XBRL Variables Specification [VARIABLES].

1.6 Namespaces and namespace prefixes

Namespace prefixes [XML NAMES] will be used for elements and attributes in the form ns:name where ns is the namespace prefix and name is the local name. Throughout this specification, the mappings from namespace prefixes to actual namespaces is consistent with Table 1.

The prefix column in Table 1 is non normative. The namespace URI column is normative.

Table 1: Namespaces and namespace prefixes
Prefix Namespace URI
uf http://xbrl.org/2008/filter/unit
xbrlufe http://xbrl.org/2008/filter/unit/error
eg http://example.com/
fn http://www.w3.org/2005/xpath-functions
link http://www.xbrl.org/2003/linkbase
xbrli http://www.xbrl.org/2003/instance
xfi http://www.xbrl.org/2008/function/instance
xbrldi http://xbrl.org/2006/xbrldi
xbrldt http://xbrl.org/2005/xbrldt
xl http://www.xbrl.org/2003/XLink
xlink http://www.w3.org/1999/xlink
xs http://www.w3.org/2001/XMLSchema
xsi http://www.w3.org/2001/XMLSchema-instance
gen http://xbrl.org/2008/generic
variable http://xbrl.org/2008/variable
iso4217 http://www.xbrl.org/2003/iso4217

1.7 XPath usage

XPath usage is identical to that in the XBRL Variables Specification [VARIABLES].

2 Syntax

This specification only provides a textual declaration of syntax constraints when those constraints are not expressed by the normative schema supplied with this specification.

Explanations of elements and attributes are only supplied when explanations are not already provided in other specifications.

Unless explicitly stated otherwise, a reference to a specific element MUST be read as a reference to that element or to any element in its substitution group.

2.1 Single-measure unit filter

A single-measure unit filter is declared by an <uf:singleMeasure> element.

The syntax for the <uf:singleMeasure> element is defined by the normative schema supplied with this specification.

The single-measure unit filter can be used to match facts that are reported with a unit that is specified by a single measure.

The XPath expression implied by a single-measure unit filter is:

xfi:is-numeric(fn:node-name(.)) and count(xfi:unit-numerator(xfi:unit(.))) eq 1 and count(xfi:unit-denominator(xfi:unit(.))) eq 0 and xfi:measure-name(xfi:unit-numerator(xfi:unit(.))[1]) eq #measure

where #measure is the value of the <uf:qnameExpression> element if that element is contained by the <uf:measure> element and #measure is given by fn:QName(#namespace, #name) if the <uf:qname> element is contained by the <uf:measure> element. #namespace is the namespace for the QName specified as the content of the <uf:qname> element and #name is the local name for the QName specified as the content of the <uf:qname> element.

Example 1: Single-measure unit filters
Filter1 Selection criteria
<uf:singleMeasure>
<uf:measure>
<uf:qname>
eg:squareMiles
</uf:qname>
</uf:measure>
</uf:singleMeasure>
The units of measurement must be reported with a single measure QName that is equal to eg:squareMiles. Non-numeric facts and facts reported with units of measurement represented by several measures are all rejected by this filter.

1. XLink attributes have been omitted.

2.2 General unit filter

A general unit filter is declared by an <uf:generalMeasures> element.

The syntax for the <uf:generalMeasures> element is defined by the normative schema supplied with this specification.

The general unit filter can be used to select facts based on criteria that involve a number of unit measures.

The XPath expression implied by a general unit filter is:

xfi:is-numeric(fn:node-name(.)) and xfi:unit(.)[#test]

where #test is the value of the @test attribute on the general unit filter.

Example 2: General unit filters
Filter1 Selection criteria
<uf:generalMeasures test="exists(xbrli:divide)"/>
The filter rejects facts if they are not reported with a unit of measure that involves both a numerator and a denominator.
<uf:generalMeasures test="count(xbrli:divide/xbrli:numerator/xbrli:measure) eq 1 and xbrli:divide/xbrli:numerator/xbrli:measure eq fn:QName('http://xbrl.org/formula/conformance/example','eg:kilometers') and count(xbrli:divide/xbrli:denominator/xbrli:measure) eq 1 and xbrli:divide/xbrli:denominator/xbrli:measure eq fn:QName('http://xbrl.org/formula/conformance/example','eg:hours')"/>
The filter rejects facts if they are not reported with a unit of measure that is expressed as a single numerator measure with a QName, eg:kilometers and a single denominator measure with a QName, eg:hours.

1. XLink attributes have been omitted.

Appendix A Normative schema

The following is the XML schema provided as part of this specification. This is normative. Non-normative versions (which should be identical to these except for appropriate comments indicating their non-normative status) are also provided as separate files for convenience of users of the specification.

NOTE: (non-normative) Following the schema maintenance policy of XBRL International, it is the intent (but is not guaranteed) that the location of non-normative versions of these schemas on the web will be as follows:

  1. While any schema is the most current RECOMMENDED version and until it is superseded by any additional errata corrections a non-normative version will reside on the web in the directory http://www.xbrl.org/2008/ - during the drafting process for this specification this directory should contain a copy of the most recent published version of the schema at http://www.xbrl.org/2008/unit-filter.xsd.
  2. A non-normative version of each schema as corrected by any update to the RECOMMENDATION will be archived in perpetuity on the web in a directory that will contain a unique identification indicating the date of the update.
<schema xmlns:uf="http://xbrl.org/2008/filter/unit" xmlns:variable="http://xbrl.org/2008/variable" xmlns="http://www.w3.org/2001/XMLSchema" targetNamespace="http://xbrl.org/2008/filter/unit" elementFormDefault="qualified">
<import namespace="http://www.xbrl.org/2003/XLink" schemaLocation="http://www.xbrl.org/2003/xl-2003-12-31.xsd"/>
<import namespace="http://xbrl.org/2008/variable" schemaLocation="variable.xsd"/>
<complexType name="qname.model">
<choice>
<element name="qname" type="QName"/>
<element name="qnameExpression" type="variable:expression"/>
</choice>
</complexType>
<element id="xml-single-measure-unit-filter" name="singleMeasure" substitutionGroup="variable:filter">
<complexType mixed="true">
<complexContent mixed="true">
<extension base="variable:resource.type">
<sequence>
<element name="measure" type="uf:qname.model"/>
</sequence>
</extension>
</complexContent>
</complexType>
</element>
<element id="xml-general-unit-filter" name="generalMeasures" substitutionGroup="variable:filter">
<complexType mixed="true">
<complexContent mixed="true">
<extension base="variable:resource.type">
<attribute name="test" type="variable:expression" use="required"/>
</extension>
</complexContent>
</complexType>
</element>
</schema>

Appendix B References

VARIABLES
XBRL International Inc.. "XBRL Variables 1.0"
Phillip Engel, Herm Fischer, Victor Morilla, Jim Richards, Geoff Shuetrim, David vun Kannon, and Hugh Wallis.
(See ../../variables/REC-2009-06-22/variables-REC-2009-06-22.html)
XBRL 2.1
XBRL International Inc.. "Extensible Business Reporting Language (XBRL) 2.1"
Phillip Engel, Walter Hamscher, Geoff Shuetrim, David vun Kannon, and Hugh Wallis.
(See http://www.xbrl.org/Specification/XBRL-RECOMMENDATION-2003-12-31+Corrected-Errata-2008-07-02.htm)
XML
W3C (World Wide Web Consortium). "Extensible Markup Language (XML) 1.0 (Fourth Edition)"
Tim Bray, Jean Paoli, C. M. Sperberg-McQueen, Eve Maler, and François Yergeau.
(See http://www.w3.org/TR/REC-xml/)
XML NAMES
W3C (World Wide Web Consortium). "Namespaces in XML 1.0 (Second Edition)"
Tim Bray, Dave Hollander, Andrew Layman, and Richard Tobin.
(See http://www.w3.org/TR/REC-xml-names/)
XML SCHEMA STRUCTURES
W3C (World Wide Web Consortium). "XML Schema Part 1: Structures Second Edition"
Henry S. Thompson, David Beech, Murray Maloney, and Noah Mendelsohn.
(See http://www.w3.org/TR/xmlschema-1/)

Appendix C Intellectual property status (non-normative)

This document and translations of it may be copied and furnished to others, and derivative works that comment on or otherwise explain it or assist in its implementation may be prepared, copied, published and distributed, in whole or in part, without restriction of any kind, provided that the above copyright notice and this paragraph are included on all such copies and derivative works. However, this document itself may not be modified in any way, such as by removing the copyright notice or references to XBRL International or XBRL organizations, except as required to translate it into languages other than English. Members of XBRL International agree to grant certain licenses under the XBRL International Intellectual Property Policy (www.xbrl.org/legal).

This document and the information contained herein is provided on an "AS IS" basis and XBRL INTERNATIONAL DISCLAIMS ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.

The attention of users of this document is directed to the possibility that compliance with or adoption of XBRL International specifications may require use of an invention covered by patent rights. XBRL International shall not be responsible for identifying patents for which a license may be required by any XBRL International specification, or for conducting legal inquiries into the legal validity or scope of those patents that are brought to its attention. XBRL International specifications are prospective and advisory only. Prospective users are responsible for protecting themselves against liability for infringement of patents. XBRL International takes no position regarding the validity or scope of any intellectual property or other rights that might be claimed to pertain to the implementation or use of the technology described in this document or the extent to which any license under such rights might or might not be available; neither does it represent that it has made any effort to identify any such rights. Members of XBRL International agree to grant certain licenses under the XBRL International Intellectual Property Policy (www.xbrl.org/legal).

Appendix D Acknowledgements (non-normative)

This document could not have been written without the contributions of many people including the participants in the Formula Working Group.

Appendix E Document history (non-normative)

DateAuthorDetails
18 December 2006Geoff Shuetrim

First internal working draft created, drawing extensively on the previous Formula specification drafts.

25 April 2007Geoff Shuetrim

Changed the target namespace of the normative schema.

08 May 2007Geoff Shuetrim

Added clarification about the fact aspect covered by the filters defined in this specification.

29 May 2007Geoff Shuetrim

Changed the target namespace of the normative schema again. Modified the general unit filter to have a structure that is more consistent with the structure used for other filters. Changed the $x notation to #x to be consistent with other filter specifications.

24 July 2007Hugh Wallis

Edited for public working draft publication.

05 November 2007Geoff Shuetrim

Converted the specification to XML format.

Added in the definitions and the hyperlinks to the relevant sections of the normative schema.

Fixed up the single measure filter naming inconsistencies.

12 November 2007Geoff Shuetrim

Linked all of the external terminology references back to bibliographic citations.

30 November 2007Geoff Shuetrim

Added examples.

Changed = operator in the XPath expressions to eq on the advice of Herm Fischer.

02 December 2007Geoff Shuetrim

Changed additional = operators in the example XPath expressions to eq on the advice of Herm Fischer.

02 December 2007Herm Fischer

Changed count(nodelist) operator to exists(nodelist) in the example XPath expressions.

31 January 2008Geoff Shuetrim

Standardised the format of the hyperlinks to the normative schema.

Changed xs:QName() to fn:QName() as suggested by Masatomo Goto.

17 April 2008Geoff Shuetrim

The QName constants in the example using kilometer and hour measures have been changed to use the fn:QName() function rather than a string representation of the QName, as suggested by Herm Fischer.

27 November 2008Geoff Shuetrim

The implied XPath expressions have been aligned to the latest versions of the functions in the XBRL function registry, resolving discrepancies identified by Nathan Summers.

15 December 2008Geoff Shuetrim

Updated references to the latest errata-corrected version of the XBRL 2.1 specification.

Appendix F Errata corrections in this document

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 Formula Working Group up to and including 22 June 2009. 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.