ClearParse is a flexible engine that can be used for any parsing task including interpreting or compiling programming languages, analyzing or converting data files, processing command line parameters and user input, implementing markup languages and scripts, natural language processing (NLP), and more.
tkscript is a JIT-accelerated C-like scripting language with bindings for OpenGL, SDL, SDL_net, libpng, and zlib. A plugin SDK can be used to dynamically extend the script engine with custom C functions and C++ classes. It can be used to create portable, 3D, OpenGL-accelerated multimedia applications.
regexp-engine is a regexp engine written entirely in Ruby that makes it possible to search in text with advanced search patterns. It supports Perl 5 and some Perl 6 syntax and is fairly compatible with Ruby's native regexp engine, passing almost 98% of the Rubicon tests. The implementation is simple and contains no optimizations.
PyBison is a sophisticated yet easy-to-use parser creation toolkit for Python that interfaces directly to Bison (yacc)-based parsers. It provides full LALR(1) grammar support, allowing for simple parsing tasks through to writing compilers for high-level languages. Parser code is automatically generated from rules within user-created Parser classes (written in Python), and then, compiled, yacc'ed and linked into a shared library, which is loaded into the running process. All this happens automatically. When the parser runs, it connects directly with the yyparse() routine, and takes event callbacks upon parse targets being reached.
Kelbt generates backtracking LALR parsers. A distinguishing characteristic of Kelbt is that it introduces a class of actions called undo actions which are invoked as the backtracker undoes parsing. These allow the user to revert any side effects of forward parsing. Kelbt enables a user-controlled parsing strategy approximating that of generalized recursive-descent parsing. This makes it easy to resolve language ambiguities by ordering the grammar productions of a nonterminal according to precedence.
Absimpa is a Java class library that provides a recursive decent parser. It is an experiment in abstraction and Java generics. It tries to include only the essentials of what makes out a parser and to leave out, or rather leave free for specification, what is not relevant for the parsing process.