1 Introduction

This specification is an extension to the XBRL Variables 1.0 Specification [VARIABLES]. It defines XML syntax [XML] for filters that can condition on entity identifiers when selecting facts from XBRL instances.

All of the filters defined in this specification can cover the entity 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 1.0 [VARIABLES].

1.2 Relationship to other work

This specification depends upon the XBRL Specification [XBRL 2.1], 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
`ef`	`http://xbrl.org/2008/filter/entity`
`xbrlefe`	`http://xbrl.org/2008/filter/entity/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 Entity identifier filter

An entity identifier filter is declared by an <ef:identifier> element.

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

The entity identifier filter can be used to match facts based upon characteristics of the entity identification scheme and/or the entity identification value.

The XPath expression implied by an entity identifier filter is constructed as follows:

xfi:identifier(.)[#test]

where #test is the value of the @test attribute on the entity identifier filter.

Example 1: Entity identifier filters

Filter `@test` attribute	Selection criteria
`string-length(xfi:identifier-value(.)) = 8`	A fact's entity identifier value must have exactly 8 characters.

2.2 Specific entity-scheme filter

A specific entity-scheme filter is declared by a <ef:specificScheme> element.

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

The specific entity-scheme filter can be used to match facts based upon whether they report values for the scheme identified by the filter.

The XPath expression implied by a specific entity-scheme filter is:

xfi:identifier-scheme(xfi:identifier(.)) eq #scheme

where #scheme is the value of the @scheme attribute on the specific entity-scheme filter.

Example 2: Specific entity-scheme filters

Filter `@scheme` attribute	Selection criteria
`'http://xbrl.my.com/entity/identification/scheme'`	A fact's entity identification scheme must be `http://xbrl.my.com/entity/identification/scheme`. Note that the quotes inside the attribute are required because the content of the `@scheme` attribute is interpreted as an XPath expression.
`xfi:identifier-scheme(xfi:identifier($eg:variableB))`	A fact's entity identification scheme must be the same as the entity identification scheme of the fact that variable `variableB` has evaluated to.

2.3 Regular-expression entity-scheme filter

A regular-expression entity-scheme filter is declared by a <ef:regexpScheme> element.

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

The regular-expression entity-scheme filter can be used to match facts based upon regular patterns in the text of the entity scheme.

The XPath expression implied by a regular-expression entity-scheme filter is:

fn:matches(xfi:identifier-scheme(xfi:identifier(.)),'#pattern')

where #pattern is the value of the @pattern attribute on the regular-expression entity-scheme filter.

Example 3: Regular-expression entity-scheme filters

Filter `@pattern` attribute	Selection criteria
`^http.+`	The entity identification scheme must start with the string `http` and then be followed by at least one character.

2.4 Specific entity-identifier filter

A specific entity-identifier filter is declared by a <ef:specificIdentifier> element.

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

The specific entity-identifier filter can be used to match facts based upon whether they report values using the entity identifier value given by the filter.

The XPath expression implied by a specific entity-identifier filter is:

(xfi:identifier-value(xfi:identifier(.)) eq #value and xfi:identifier-scheme(xfi:identifier(.)) eq #scheme)

where #value is the value of the @value attribute on the specific entity-scheme filter and #scheme is the value of the @scheme attribute on the specific entity-identifier filter.

Example 4: Specific entity-identifier filters

Filter `@scheme` attribute	Filter `@value` attribute	Selection criteria
`http://my.com/entity/identification/scheme`	`1234-ASDF`	The entity identification scheme must be `http://my.com/entity/identification/scheme` and the entity identification value must be `1234-ASDF`.

2.5 Regular-expression entity-identifier filter

A regular-expression entity-identifier filter is declared by a <ef:regexpIdentifier> element.

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

The regular-expression entity-identifier filter can be used to match facts based upon regular patterns in the text of the entity identifier value.

The XPath expression implied by a regular-expression entity-identifier filter is:

fn:matches(xfi:identifier-value(xfi:identifier(.)),'#pattern')

where #pattern is the value of the @pattern attribute on the regular-expression entity-identifier filter.

Example 5: Regular-expression entity-identifier filters

Filter `@pattern` attribute	Selection criteria
`[a-z]{4}\-[0-9]{4}`	The entity identification value must start with a string of 4 lower case letters in the range `a-z` followed by a hyphen and then 4 digits in the range `0-9`.

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:

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/entity-filter.xsd.
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.

</extension>

</complexContent>

</complexType>

</element>

</extension>

</complexContent>

</complexType>

</element>

</extension>

</complexContent>

</complexType>

</element>

</extension>

</complexContent>

</complexType>

</element>

</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/CR-2008-12-31/variables-CR-2008-12-31.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)

Date	Author	Details
18 December 2006	Geoff Shuetrim	First internal working draft created, drawing extensively on the previous formula specification drafts
25 April 2007	Geoff Shuetrim	Changed the target namespace for the normative schema.
29 May 2007	Geoff Shuetrim	Changed the target namespace of the normative schema again. Changed the implied XPath expressions to be consistent with the structures used for the period filters. Changed XPath expression references to $x to #x to be consistent with other filter specifications. Changed the value attribute data types to allow XPath 2.0 expressions rather than constants.
25 June 2007	Geoff Shuetrim	Added material to the introduction on the implications of entity filters for implicit filtering.
24 July 2007	Hugh Wallis	Edited for public working draft publication.
05 November 2007	Geoff Shuetrim	Converted the specification to XML format. Added in the definitions and the hyperlinks to the relevant sections of the normative schema. Added comments about simplifications that should be made.
23 November 2007	Geoff Shuetrim	Eliminated comments relating to how regular expression filters could become obsolete once we have an entity link. In the meantime, the regular expression filters are useful. Clarified and hyperlinked the details for aspect covering.
26 November 2007	Jim Richards	Added a reference to extending Variables 1.0 Specification to the Abstract. Also expanded [VARIABLES] in Introduction.
29 November 2007	Geoff Shuetrim	Clarified which aspect is covered by the concept filters.
30 November 2007	Geoff Shuetrim	Fixed the name of the `xfi:entity:identifier` function in the implied XPath expressions. Added examples.
31 January 2008	Geoff Shuetrim	Standardised the format of the hyperlinks to the normative schema.
12 February 2008	Geoff Shuetrim	Converted remaining general equality tests to value equality tests in the implied XPath expressions.
07 March 2008	Geoff Shuetrim	Fixed `xfi:identifier` function name in the examples as suggested by Takahide Muramoto.
18 March 2008	Geoff Shuetrim	Ensured that the entity identifier filter syntax described in the text aligns everywhere with the syntax of the normative schema.

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 31 December 2008. 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.

Entity Filters 1.0

Candidate Recommendation 31 December 2008

Status

Abstract

Table of Contents

Appendices

Table

Examples

Definitions

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 Entity identifier filter

2.2 Specific entity-scheme filter

2.3 Regular-expression entity-scheme filter

2.4 Specific entity-identifier filter

2.5 Regular-expression entity-identifier filter

Appendix A Normative schema

Appendix B References

Appendix C Intellectual property status (non-normative)

Appendix D Acknowledgements (non-normative)

Appendix E Document history (non-normative)

Appendix F Errata corrections in this document