btparse is a C library for parsing and processing BibTeX files.
It provides a lexical scanner and LR parser (constructed by PCCTS),
both of which are efficient and offer good error detection and
recovery; a set of functions for traversing the AST (abstract
syntax tree) generated by the parser; and utility functions for
manipulating strings according to BibTeX conventions.

WWW: http://www.gerg.ca/software/btOOL