A JSONPath parser written in C++, targeting C++17.
This project is a work in progress. So far we have a lexer producing a std::vector<Token>, and a parser that parses those tokens into a std::vector<std::variant<Segment, RecursiveSegment>>. When a segment includes a filter selector, that filter selector's expression member is effectively the root of a parse tree for the filter expression. See include/libjsonpath/selectors.hpp for a description of segment, selector and filter expression nodes.
This example parses a JSONPath query string from the command line and prints a canonical representation of the resulting structure.
#include "libjsonpath/jsonpath.hpp"
#include <iostream>
int main(int argc, const char* argv[]) {
if (argc != 2) {
std::cout << "usage: " << argv[0] << " <path>" << std::endl;
std::exit(1);
}
auto path{libjsonpath::parse(argv[1])};
std::cout << libjsonpath::to_string(path) << std::endl;
return 0;
}Given the query $.foo.bar[?@.some > $.thing], we get the following printed to the terminal.
$['foo']['bar'][?@['some'] > $['thing']]
Benchmarks are excluded from the ALL target and should be built in "Release" mode.
$ cmake -DLIBJSONPATH_BUILD_BENCHMARKS=ON -DCMAKE_BUILD_TYPE=Release -S . -B build_bench
$ cmake --build build_bench --config Release --target lexer_benchmarks --target parser_benchmarks
$ cd build_bench
$ ./lexer_benchmark
$ ./parser_benchmark