Swift Technical overview
This section attempts to provide a technical overview of the Swift architecture.
The execution layer causes an application program (in the form of a unix executable) to be executed either locally or remotely
The two main choices are local unix execution and execution through GRAM. Other options are available, and user provided code can also be plugged in.
The kickstart utility can be used to capture environmental information at execution time to aid in debugging and provenance capture
Swift script language compilation layer
Step i: text to XML intermediate form parser/processor. parser written in ANTLR - see resources/VDL.g. The XML Schema Definition (XSD) for the intermediate language is in resources/XDTM.xsd.
Step ii: XML intermediate form to Karajan workflow. Karajan.java - reads the XML intermediate form. compiles to karajan workflow language - for example, expressions are converted from Swift script syntax into Karajan syntax, and function invocations become karajan function invocations with various modifications to parameters to accomodate return parameters and dataset handling.
Swift/karajan library layer
Some Swift functionality is provided in the form of Karajan libraries that are used at runtime by the Karajan workflows that the Swift compiler generates.