The Lean Mean C++ Option Parser handles program arguments (argc, argv). It supports the short and long option formats of getopt(), getopt_long(), and getopt_long_only(), but has a more convenient interface. It is a freestanding, header-only library with no dependencies, not even libc or STL. It comes with a usage message formatter which supports column alignment and line wrapping, making it ideal for localized messages with different lengths.
The Parsing Expression Grammar Template Library (PEGTL) is a C++0x library for creating parsers according to a Parsing Expression Grammar (PEG). Grammars are embedded as regular C++ code, created with template programming (not template meta programming). These hierarchies naturally correspond to the inductive definition of PEGs. The library extends on the subject of PEGs with new expression types, actions that can be attached to grammar rules, and mechanisms to ensure helpful diagnostics in case of parsing errors. PEGs are superficially similar to Context-Free Grammars (CFGs).
Piglet is a tool for parsing and lexing text for the .NET framework. The purpose of Piglet is to provide an easy-to-use tool for parsing text which can be easily included in any .NET project as a single assembly. In contrast to most parser generators, Piglet provides a fluent interface which enables you to express your grammar in a syntax which is accessible for users with no prior experience of parser generators. Piglet generates efficient, type safe, and reentrant LALR(1) parsers at runtime, which saves you from having a pre-compile step to generate your parsing tables. It also includes a lexical scanner generator which can be used independently of the parser generator.