FSML takes advantage of the eXtensible Markup Language's hierarchical structure. This hierarchical structure gives XML and consequently FSML the ability to easily represent data structures as well as describe processes. FSML uses these capabilities to capture file parameters, data types, and semantics, as well as the process to be used for reading and writing data to the file.
Figure 1 shows how the information captured in an FSML document might be used. In the figure, a legacy application generates output files (A and B) whose structures have been described by the corresponding FSML documents. An FSML Processor (software that interprets FSML to read and write file structures described by FSML) can then read the files generated by the application and stores that information in memory. The processor can next be directed to write input files (C and D) for another application based on the corresponding FSML documents using data from the read output files, and data supplied by other means (user, database, etc.). Another legacy application can then run using those generated input files.
Any number of applications - legacy or current - could communicate in this way. In addition, the FSML Processor could be linked to databases and other non-legacy applications that use the data extracted from the output files of a legacy application, and/or supply input for another legacy application.
It is vital that the user understand FSML's basic progression. The processor reads a file, stores that data in memory, (optionally) manipulates that data, and then (optionally) writes another file. That means that all data to be written must either reside in memory (after being read from the first file) or be hardcoded in the FSML file. Always remember that FSML simultaneously describes how to read and how to write.
