main.cpp

// To view the license please visit
// https://github.com/IDNI/parser/blob/main/LICENSE.md

// CSV parser tutorial - part 4
//
// In this part we enhance the parser for parsing also negative integers.

#include <optional>
#include <limits>

#include "parser.h"

#ifdef min
#	undef min
#endif
#ifdef max
#	undef max
#endif

using namespace std;
using namespace idni;

struct csv_parser {
	csv_parser() :
		cc(predefined_char_classes({ "digit" }, nts)),
		start(nts("start")), digit(nts("digit")),
		// add digits nonterminal which represents a sequence of digits
		digits(nts("digits")),
		g(nts, rules(), start, cc), p(g) {}
	optional<int_t> parse(const char* data, size_t size) {
		auto res = p.parse(data, size);
		optional<int_t> i{};
		if (!res.found)	return cerr << res.parse_error << '\n', i;
		i = res.get_terminals_to_int(res.get_forest()->root());
		if (!i)	return cerr << "out of range, allowed range is from: "
				<< numeric_limits<int_t>::min() << " to: "
				<< numeric_limits<int_t>::max() << '\n', i;
		return i;
	}
private:
	nonterminals<> nts;
	char_class_fns<> cc;
	prods<> start, digit, digits;
	grammar<> g;
	parser<> p;
	prods<> rules() {
		prods<> r, minus('-'); // create a minus terminal for '-'
		// digits is a sequence of digits (was start in previous part)
		r(digits, digit | (digit + digits));
		// start now can be a sequence of digits or the minus terminal
		// followed by a sequence of digits
		r(start,  digits | (minus + digits));
		return r;
	}
};

int main() {
	cout << "Validator for integers. "
		<< "Enter an integer per line or Ctrl-D to quit\n";
	csv_parser p;
	string line;
	while (getline(cin, line)) {
		cout << "entered: `" << line << "`\n";
		auto i = p.parse(line.c_str(), line.size());
		if (i) cout << "parsed integer: " << i.value() << '\n';
	}
}