Combining programs to perform more powerful actions using scripting languagesseems a good idea, until portability and parallel execution on computingclusters become the main concerns of the script. GNU Guix used GNU Guile as adomain-specific language to describe software packages. In the same way, thecomponents that make up a workflow description can be expressed using GNUGuile. In this talk I would like to present the work I have done to implement asimple workflow language and a workflow execution engine (both in GNU Guile)to run programs on computing clusters.