How Data Files Work

Figure 1: Call structure of three simple project schemes: driver, chain, and pyramid.

In brief, data files are plain text files containing program commands. They are created in the i Editor pane, and they are run in any one of the following ways.

• using the program call command at the command prompt,

• using the Execute button on the toolbar ( ) from the i Editor pane containing the file,

• running a selected excerpt of the data file using the Execute Selected button on the toolbar ( ), or

• using the i Open Item dialog and specifying the option “Data File: Call”.

In addition, the program call command offers additional refinements, including the ability to run a file from a specific line, or from a label within the file, or to run a set of files specified within a single command.

Data files may call one another, though recursive calls are not allowed. There is no limit to the amount of nesting possible. As the illustration begins to suggest, there are innumerable ways to relate data files to one another and to structure a project — this is one of the great strengths of the command-driven design of the program.