3 Terminology

This chapter is normative.

The connection between a model item in the XForms Model and a form control in the XForms User Interface, or other presentation. Can also refer to the connection between a model item and its representation as a instance data item.
binding expression
An addressing expression used by the binding to connect form controls to other parts of XForms.
Data Structures Component
The portion of the XForms Model that defines model items along with the structure of the associated instance data.
A single defining aspect of a value space. Generally speaking, each facet characterizes a value space along independent axes or dimensions.
form control
A user interface control or "widget" that serves as a point of user interaction. The XForms User Interface defines several form controls.
instance data
Representation of the values of all the model items. When represented as XML, instance data can be accessed through the XML DOM.
instance data item
Representation of a single piece of data, constrained by the definition of a model item, and typically presented to the user through one or more form controls.
lexical space
A lexical space is the set of valid literals for a datatype.
model item
An abstract unit of data-collection within the XForms Model, which defines a type and possibly other constraints on a single piece of collected data.
value space
A set of values for a given datatype. Each value in the value space of a datatype is denoted by one or more literals in its lexical space.
XForms Extensions Component
The portion of the XForms Model that extends the Data Structures component with constraints, dependencies, a Dynamic Constraints Language, and calculations.
XForms Model
The non-visible definition of an XML form as specified by XForms. The XForms Model defines the model items that exist, the structure of the instance data to represent the data, and constraints and other run-time aspects of XForms.
XForms Processor
A software application or program that conforms to the XForms specification.
XForms Submit Protocol
The means by which instance data is transported from one place to another, such as part of a submit, suspend, or resume operation.
XForms User Interface
A set of graphical form controls designed to provide a higher-quality user experience when compared to conventional XHTML forms.