Imagine you need to apply the same sequence of tools to a set of data files, and possibly want to be able to repeat the experiment later, i.e. sometime in future you will want recall how precisely the processing would be invoked. One example is a shared task in processing of similarly formatted data in many languages. One may want to use make and Makefiles where the sequence of application of the various scripts can be well described. However, dealing with some phenomena of such sort of processing is rather tricky in classical Makefiles.

The most prominent phenomenon that is difficult to capture is what I call multidimensionality of the data. Every data file undergoes a sequence of processing steps, i.e. it appears in many different states (and intermediate data formats). Some processing tools may have alternative implementations, so you may have the same piece of data in the same stage of processing (e.g. syntactically parsed) but with different processing results (e.g. parsed either by Malt parser, or MST parser).