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101 lines
3.0 KiB
C++
101 lines
3.0 KiB
C++
/**
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* Alee Forth: A portable and concise Forth implementation in modern C++.
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* Copyright (C) 2023 Clyne Sullivan <clyne@bitgloo.com>
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*
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* This program is free software: you can redistribute it and/or modify
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* it under the terms of the GNU Lesser General Public License as published by
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* the Free Software Foundation, either version 3 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public License
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* along with this program. If not, see <https://www.gnu.org/licenses/>.
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*/
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#include "corewords.hpp"
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#include "parser.hpp"
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#include <cctype>
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#include <cstdlib>
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ParseStatus Parser::parse(State& state, std::string_view& str)
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{
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auto addr = Dictionary::Input;
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state.dict.write(addr, str.size() + 1);
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addr += sizeof(Cell) + Dictionary::InputCells - str.size() - 1;
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for (char c : str)
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state.dict.writebyte(addr++, c);
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state.dict.writebyte(addr, '\0');
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return parseSource(state);
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}
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ParseStatus Parser::parseSource(State& state)
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{
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auto word = state.dict.input();
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while (word.size() > 0) {
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if (auto ret = parseWord(state, word); ret != ParseStatus::Finished)
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return ret;
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word = state.dict.input();
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}
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return ParseStatus::Finished;
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}
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ParseStatus Parser::parseWord(State& state, Word word)
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{
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if (auto i = CoreWords::findi(state, word); i >= 0) {
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if (state.compiling())
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state.dict.add(i & ~CoreWords::CoreImmediate);
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else if (state.dict.equal(word, ":"))
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state.compiling(true);
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if (!state.compiling() || (i & CoreWords::CoreImmediate))
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CoreWords::run(i & ~CoreWords::CoreImmediate, state);
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} else if (auto j = state.dict.find(word); j > 0) {
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auto e = state.dict.getexec(j);
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if (state.compiling()) {
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if (state.dict.read(j) & CoreWords::Immediate) {
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state.compiling(false);
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state.execute(e);
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state.compiling(true);
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} else {
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state.dict.add(CoreWords::HiddenWordJump);
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state.dict.add(e);
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}
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} else {
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state.execute(e);
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}
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} else {
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char buf[word.size() + 1];
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for (unsigned i = 0; i < word.size(); ++i)
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buf[i] = state.dict.readbyte(word.start + i);
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buf[word.size()] = '\0';
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char *p;
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const auto base = state.dict.read(0);
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const Cell l = std::strtol(buf, &p, base);
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if (std::distance(buf, p) == word.size()) {
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if (state.compiling()) {
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state.dict.add(CoreWords::HiddenWordLiteral);
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state.dict.add(l);
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} else {
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state.push(l);
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}
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} else {
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return ParseStatus::NotAWord;
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}
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}
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return ParseStatus::Finished;
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}
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