From the webpage:
tm (shorthand for Text Mining Infrastructure in R) provides a framework for text mining applications within R.
The tm package offers functionality for managing text documents, abstracts the process of document manipulation and eases the usage of heterogeneous text formats in R. The package has integrated database backend support to minimize memory demands. An advanced meta data management is implemented for collections of text documents to alleviate the usage of large and with meta data enriched document sets.
With the package ships native support for handling the Reuters-21578 data set, Gmane RSS feeds, e-mails, and several classic file formats (e.g. plain text, CSV text, or PDFs).
Admittedly, the “tm” caught my attention but a quick review confirmed that the package could be useful to topic map authors.