13. A computer system according to claim 12 , wherein: the plurality of workflow definition constructs are provided as XML commands that are then used as annotations to the source code and the classes.
12. A computer system capable of extending an existing programming language, comprising: a computer including a processing device operating thereon; a program source file stored on a computer readable storage medium, wherein the program source file includes a source code and classes written in an existing object oriented programming language, wherein the existing object oriented programming language is extended with a workflow language including a plurality of workflow constructs provided as markup language commands; a workflow definition including the plurality of workflow constructs of the workflow language, wherein the workflow constructs are specified in the form of annotations to the source code and the classes, the plurality of workflow constructs including an action construct representing an activity that allows a first software component to call an operation on a second software component; and object code executed by the processor, the object code configured to use a workflow program according to the workflow definition, including processing, using a computer including a processing device operating thereon, the action construct to allow the first software component to call the operation on the second software component, and pass information selected from one or more files, documents and/or tasks between system resources, according to a set of procedural rules to generate activities at the computer as defined by the workflow definition specified in the form of annotations to the source code and classes.