This International Standard specifies the semantics and syntax of DXL. DXL is a language for exchanging tree-structured charts among CASE tools. DXL is applicable to: 1. exchanging ISO/IEC 8631 compliant tree-structured charts (examples of which are shown in annex A (informative) of ISO/IEC 8631); 2. exchanging program flowcharts defined in ISO/IEC 5807 if they are well-structured and don't have data defined in ISO/IEC 5807; and 3. describing procedure oriented algorithms. This International Standard does not specify: 1. graphical information about a chart, such as the shape, size, and location of symbols; 2. configuration information of a chart, such as its version, author, and file name; or 3. information about the data used in the algorithm described by DXL, such as its structure, reading and writing, and declaration.