alee-forth/alee.cpp

/**
 * Alee Forth: A portable and concise Forth implementation in modern C++.
 * Copyright (C) 2023  Clyne Sullivan <clyne@bitgloo.com>
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Lesser 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 Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License
 * along with this program.  If not, see <https://www.gnu.org/licenses/>.
 */

#include "libalee/alee.hpp"
#include "memdict.hpp"

#include <charconv>
#include <fstream>
#include <iostream>
#include <vector>

#ifdef ALEE_MSP430
#include "lzss.h"
static const
#include "msp430fr2476_all.h"
static Error findword(State&, Word);
#endif // ALEE_MSP430

static bool okay = false;

static void readchar(State&);
static void parseLine(State&, const std::string&);
static void parseFile(State&, std::istream&);

int main(int argc, char *argv[])
{
    MemDict dict;
    State state (dict, readchar);
#ifdef ALEE_MSP430
    Parser::customParse = findword;
#endif // ALEE_MSP430

    dict.initialize();
    CoreWords::initialize(state);

    {
        std::vector args (argv + 1, argv + argc);
        for (const auto& a : args) {
            std::ifstream file (a);
            parseFile(state, file);
        }
    }

    okay = true;
    parseFile(state, std::cin);

    return 0;
}

static void readchar(State& state)
{
    auto idx = state.dict.read(Dictionary::Input);
    auto addr = static_cast<Addr>(Dictionary::Input + sizeof(Cell) + idx);

    auto c = static_cast<char>(std::cin.get());
    if (isupper(c))
        c += 32;
    state.dict.writebyte(addr, c ? c : ' ');
}

static void save(State& state)
{
    std::ofstream file ("alee.dat", std::ios::binary);

    if (file.good()) {
        for (Addr i = 0; i < state.dict.here(); ++i)
            file.put(state.dict.readbyte(i));
    }
}

static void load(State& state)
{
    std::ifstream file ("alee.dat", std::ios::binary);

    for (Addr i = 0; file.good(); i++)
        state.dict.writebyte(i, file.get() & 0xFFu);
}

void user_sys(State& state)
{
    char buf[32] = {0};

    switch (state.pop()) {
    case 0: // .
        std::to_chars(buf, buf + sizeof(buf), state.pop(),
                      state.dict.read(Dictionary::Base));
        std::cout << buf << ' ';
        break;
    case 1: // unused
        state.push(static_cast<Addr>(state.dict.capacity() - state.dict.here()));
        break;
    case 2: // emit
        std::cout << static_cast<char>(state.pop());
        break;
    case 3: // save
        save(state);
        break;
    case 4: // load
        load(state);
        break;
    default:
        break;
    }
}

void parseLine(State& state, const std::string& line)
{
    if (auto r = Parser::parse(state, line.c_str()); r == Error::none) {
        if (okay)
            std::cout << (state.compiling() ? " compiled" : " ok") << std::endl;
    } else {
        switch (r) {
        case Error::noword:
            std::cout << "word not found in: " << line << std::endl;
            break;
        case Error::push:
            std::cout << "stack overflow" << std::endl;
            break;
        case Error::pushr:
            std::cout << "return stack overflow" << std::endl;
            break;
        case Error::popr:
            std::cout << "return stack underflow" << std::endl;
            break;
        case Error::pop:
        case Error::top:
        case Error::pick:
            std::cout << "stack underflow" << std::endl;
            break;
        default:
            std::cout << "unknown error" << std::endl;
            break;
        }

        state.reset();
    }
}

void parseFile(State& state, std::istream& file)
{
    while (file.good()) {
        std::string line;
        std::getline(file, line);

        if (line == "bye")
            exit(0);

        parseLine(state, line);
    }
}

#ifdef ALEE_MSP430
#define LZSS_MAGIC_SEPARATOR (0xFB)

static char lzword[32];
static int lzwlen;
static char lzbuf[32];
static char *lzptr;

Error findword(State& state, Word word)
{
    char *ptr = lzword;
    for (auto it = word.begin(&state.dict); it != word.end(&state.dict); ++it) {
        *ptr = *it;
        if (islower(*ptr))
            *ptr -= 32;
        ++ptr;
    }
    lzwlen = (int)(ptr - lzword);

    lzptr = lzbuf;
    lzssinit(msp430fr2476_all_lzss, msp430fr2476_all_lzss_len);

    auto ret = decode([](int c) {
        if (c != LZSS_MAGIC_SEPARATOR) {
            *lzptr++ = (char)c;
        } else {
            if (lzwlen == lzptr - lzbuf - 2 && std::equal(lzbuf, lzptr - 2, lzword)) {
                lzwlen = (*(lzptr - 2) << 8) | *(lzptr - 1);
                return 1;
            } else {
                lzptr = lzbuf;
            }
        }
        return 0;
    });

    if (ret == EOF) {
        return Error::noword;
    } else {
        Parser::processLiteral(state, (Cell)lzwlen);
        return Error::none;
    }
}
#endif // ALEE_MSP430