sforth/main.cpp

/// sforth, an implementation of forth
/// Copyright (C) 2024  Clyne Sullivan <clyne@bitgloo.com>
///
/// This program is free software: you can redistribute it and/or modify it
/// under the terms of the GNU General Public License as published by the Free
/// Software Foundation, either version 3 of the License, or (at your option)
/// any later version.
///
/// This program is distributed in the hope that it will be useful, but WITHOUT
/// ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
/// FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
/// more details.
///
/// You should have received a copy of the GNU General Public License along
/// with this program.  If not, see <http://www.gnu.org/licenses/>.

#include "sforth/forth.hpp"

#include <array>
#include <fstream>
#include <iostream>
#include <span>
#include <string>

constinit static sforth::forth<4096> forth {sforth::initialize<&forth>()};

static void putu(sforth::addr v)
{
    char buf[32] = {};
    auto ptr = buf + sizeof(buf);
    *--ptr = '\0';
    do {
        *--ptr = "0123456789abcdefghijklmnopqrstuvwxyz"[v % forth.base];
    } while (v /= forth.base);
    std::cout << ptr << ' ';
}

constinit static sforth::native_word<".", [](auto) {
    sforth::addr v = forth.pop();
    if (v & (1 << (8 * sizeof(sforth::cell) - 1)))
        std::cout << '-';
    putu(v);
}> dot;
constinit static sforth::native_word<"U.", [](auto) {
    putu(forth.pop());
}, &dot> udot;
constinit static sforth::native_word<"EMIT", [](auto) {
    std::cout << static_cast<char>(forth.pop());
}, &udot> emit;
constinit static sforth::native_word<"TYPE", [](auto) {
    const unsigned u = forth.pop();
    const auto caddr = reinterpret_cast<const char *>(forth.pop());
    std::cout << std::string_view{caddr, u};
}, &emit> type;

static bool parse_stream(auto&, std::istream&, bool say_okay = false);

int main(int argc, const char *argv[])
{
    std::span args (argv + 1, argc - 1);

    dot.next = std::exchange(forth.next, &type);

    for (auto arg : args) {
        if (std::ifstream file {arg}; parse_stream(forth, file))
            return 0;
    }

    parse_stream(forth, std::cin, true);
}

bool parse_stream(auto &fth, std::istream& str, bool say_okay)
{
    std::string line;

    while (str.good()) {
        std::getline(str, line);
        if (!line.empty()) {
            for (auto& ch : line) {
                if (ch >= 'a' && ch <= 'z')
                    ch = ch - 'a' + 'A';
            }

            if (line == "BYE")
                return true;

            try {
                fth.parse_line(line);
            } catch (sforth::error e) {
                std::cerr << sforth::error_string(e) << " in " << line << std::endl;
                continue;
            }
        }

        if (say_okay)
            std::cout << (fth.compiling ? "compiled" : "ok") << std::endl;
    }

    return false;
}