This is a parser combinator library for C++. As a quick example of use, here is a complete program that parses one or more doubles separated by commas, ignoring whitespace:

#include <boost/parser/parser.hpp>

#include <iostream>
#include <string>


namespace bp = boost::parser;

int main()
{
    std::cout << "Enter a list of doubles, separated by commas.  No pressure. ";
    std::string input;
    std::getline(std::cin, input);

    auto const result = bp::parse(
        input, bp::double_ >> *(',' >> bp::double_), bp::ws);

    if (result) {
        std::cout << "Great! It looks like you entered:\n";
        for (double x : *result) {
            std::cout << x << "\n";
        }
    } else {
        std::cout
            << "Good job!  Please proceed to the recovery annex for cake.\n";
    }
}

This library is header-only, and has no Boost dependencies by default.

Features:

• Parsers that parse a variety of things.
• Combining operations that make complex parsers out of simpler ones.
• Multiple ways of getting data out of the parse, including via callbacks.
• Sentinel- and range-friendly.
• Very Unicode friendliness.
• Excellent error reporting, via diagnostics like those produced by GCC and Clang.
• Trace support for debugging your parsers.
• Clever hacks to make compile time errors easier to deal with. (These are totally optional.)

This library first appeared in Boost 1.87.0

Master status:

Develop status: