PSPZap uses five files (including source construct and target construct) as follows:

The source construct file identifies constructs in the input data file. The target construct file identifies constructs in the output data file. A construct file may be used as source in one PSPZap run, then as target in another run. The usage (source or target) does not usually change the content of the file itself.

All construct files have the same layout, and can be edited using any text editor. Each record in a construct file has four components: description, length, levels (3x) and formula. A typical record looks like this:

Briefly, in the above record the construct Comp has a maximum length of one line (in the input data file), has the first construct level set to 10 and has a construct formula which references four other constructs - F1, IF, Relop and F2.

There is quite a bit of flexibility in construct records, particularly in the construct formula component. The PSPZap User Guide provides much more detail on how you define construct records and their components. Both construct files and transform files may include comments and blank lines, so can be quite easy to read.