Filename extension .scxml Extended from XML | Type of format Markup language | |
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Latest release 1.0(September 1, 2015) Website |
SCXML stands for State Chart XML: State Machine Notation for Control Abstraction. It is an XML-based markup language that provides a generic state-machine-based execution environment based on Harel statecharts.
Contents
SCXML is able to describe complex finite state machine. For example, it is possible to describe notations such as sub-states, parallel states, synchronization, or concurrency, in SCXML.
Goals
The objective of this standard is to genericize state diagram notations that are already used in other XML contexts. For example, it is expected that SCXML notations will replace the State machines notations used in the next CCXML 2.0 version (an XML standard designed to provide telephony support to VoiceXML). It could also be used as a multimodal control language in the Multimodal Interaction Activity.
One of the goals of this language is to make sure that the language is compatible with CCXML and that there is an easy path for existing CCXML scripts to be converted to SCXML without major changes to the programming model or document structure (for example, by using an XSL Transformation).
The current version of the specification was released by the W3C in September 2015.
Examples
According to the W3C State Chart XML (SCXML): State Machine Notation for Control Abstraction specification, SCXML is a general-purpose event-based state machine language that can be used in many ways, including:
The W3C Voice Extensible Markup Language (VoiceXML) 3.0 specification includes State Chart and SCXML Representation to define functionality.
Truly multimodal applications should allow the user to communicate through the interface most suitable for the context of the interaction. Consider an application that has voice as well as the mobile phones display and keyboard as interfaces. The user will favor the most effective interface and can make a voice request to avoid excessive typing and then “click” on a list or map on the display instead of listening to long descriptions of available options. SCXML makes it easy to do several things in parallel, and the Interaction Manager SCXML application will maintain the synchronization between Voice and Visual dialogues.
The W3C document Authoring Applications for the Multimodal Architecture describes a multimodal system that implements the W3C Multimodal Architecture and gives an example of a simple multimodal application authored using various W3C markup languages, including SCXML, CCXML, VoiceXML 2.1 and HTML.
Here is the state chart diagram that describes the behavior of a stopwatch:
The SCXML file describing the transitions in this diagram is:
(Apache Licensed, see on this page)
Implementations
Inactive implementations
The following implementations are inactive, i.e., the last change to their source code was made more than two years ago: