[plt-scheme] String functions in Dr. Scheme

After installing the PLT release, the doc folder contains all of the
related documentation (the documentation on the website is convenient
too, because you can download PDFs that are ready for printing if so
desired).

What I always do after installing PLT is to bookmarks the most useful bookmarks:

/doc/r5rs/index.htm          Revised^5 Report on the Algorithmic Language Scheme
/doc/mzscheme/index.htm PLT MzScheme: Language Manual
/doc/mzlib/index.htm        PLT MzLib: Libraries Manual

The ones most interesting to you, to answer your questions about
string functions, would be the R5rs and the the mzscheme docs.