Works and expressions
Listing and fetching works and expressions.
Two important concepts that are an essential part of the API are works and expressions.
- A Work is a piece of legislation, such as an act, regulation or by-law. A work may be amended over time and may even have its title changed. A work is uniquely identified by a work FRBR URI which never changes.
- An Expression is a version of a Work in specific language at a particular point in time. A work can have many expressions, usually one for each official language and amendment. An expression is uniquely identified by its own expression FRBR URI, which is derived from the work's FRBR URI.
An example of a work is the South African Employment Equity Amendment Act, 2013 (Act 55 of 1998) with unique work FRBR URI
/akn/za/act/1998/55. This act has been amended a number of times since it was first passed. Each amended version (also called a point in time) is a unique expression of the work.
The English expression of the work, as it was amended on 17 January 2014, is uniquely identified by the expression FRBR URI
/act/1998/55/eng@2014-01-17. You can see that this is built from the work's URI, with a language code
engand the expression date
When fetching details from the API, you are always fetching details for a particular expression of the work. The expression will also include information related to the expression's work, such as the work's FRBR URI and publication information. Even if you don't specific a particular date for the expression, the API will return the latest expression applicable for the date of the request.
List works for a place
Supported content types: JSON, PDF, ePub, zip
A single expression
Supported content types: JSON, HTML, PDF, ePub, zip
The fields of the work and expression endpoints are described in the table below.
The fields of the
amendmentsproperty of the response are described below. These are the amendments that have been applied to produce this particular expression.
The items in the
commencementsproperty describe the various commencements that apply to this work, and are the same for all expressions.
In most cases, either the work is not commenced or a single work commences all of the work's provisions. In some edge cases, different provisions commence at different times and these objects describe those events.
In some extreme cases, the work that performed the commencement, or the commencement date, might not be known.
The fields of the
points_in_timeproperty of the response are described below. These are all the available points in time available for this work.
Works may be amended and change over time. You can fetch different amended versions of a work by specifying the language and date in the FRBR URI of the request.
The available points in time of a work are listed in the
points_in_timefield of the JSON description of the work. Each point in time includes a date and a list of expressions available at that date, one for each available language.
To fetch the very first expression of a work, use
frbr-uri/:language@, for example:
To fetch a specific point in time, use
frbr-uri/:language@:date, for example:
To fetch the most recent point in time at or before a specific date, use
frbr-uri/:language::date, for example
.formatpart of the FRBR URI is placed after the
If you use
@to specify a particular date and the API doesn't have a version at exactly that date, it will return a 404 response. If you need the expression of the work closest to a particular date, use