This library contains functionality for parsing and pretty-printing
S-expressions. In addition to that it contains an extremely useful
preprocessing module for Camlp4, which can be used to automatically
generate code from type definitions for efficiently converting
OCaml-values to S-expressions and vice versa. In combination with the
parsing and pretty-printing functionality this frees users from having
to write their own I/O-routines for datastructures they
define. Possible errors during automatic conversions from
S-expressions to OCaml-values are reported in a very human-readable
way. Another module in the library allows you to extract and replace
sub-expressions in S-expressions.