TPL is short for "Text Processing Library". It is a spirit/xpressive like library. I used spirit/xpressive. But the codes based on spirit or xpressive was compiled slowly. Here are some hints of TPL: * It is simple. * It will always be compiled fast. * It is based on Boost-Memory (still is a sandbox library). Here is an example of TPL: #include <stack> #include <tpl/RegExp.h> #include <tpl/ext/Calculator.h> #include <cmath> using namespace tpl; void calculate2() { typedef SimpleImplementation impl; // ---- define rules ---- impl::Allocator alloc; std::stack<double> stk; impl::Grammar::Var rFactor; impl::Grammar rMul( alloc, '*' + rFactor/calc<std::multiplies>(stk) ); impl::Grammar rDiv( alloc, '/' + rFactor/calc<std::divides>(stk) ); impl::Grammar rTerm( alloc, rFactor + *(rMul | rDiv) ); impl::Grammar rAdd( alloc, '+' + rTerm/calc<std::plus>(stk) ); impl::Grammar rSub( alloc, '-' + rTerm/calc<std::minus>(stk) ); impl::Grammar rExpr( alloc, rTerm + *(rAdd | rSub) ); impl::Rule rFun( alloc, "sin"/calc(stk, sin) | "cos"/calc(stk, cos) | "pow"/calc(stk, pow) ); rFactor.assign( alloc, real()/assign(stk) | '-' + rFactor/calc<std::negate>(stk) | '(' + rExpr + ')' | (gr(c_symbol()) + '(' + rExpr % ',' + ')')/(gr(rFun) + '(') | '+' + rFactor ); // ---- do match ---- for (;;) { std::string strExp; std::cout << "input an expression (q to quit): "; if (!std::getline(std::cin, strExp) || strExp == "q") { std::cout << '\n'; break; } try { while ( !stk.empty() ) stk.pop(); if ( !impl::match(strExp.c_str(), rExpr + eos(), skipws(), alloc) ) std::cout << ">>> ERROR: invalid expression!\n"; else std::cout << stk.top() << '\n'; } catch (const std::logic_error& e) { std::cout << ">>> ERROR: " << e.what() << '\n'; } } } // ------------------------------------------------------------------------- If you are interested in TPL, you can check out its source code from SVN: svn checkout http://libtpl.googlecode.com/svn/trunk/