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108 lines
3.4 KiB
C++
108 lines
3.4 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 "executor.hpp"
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#include "parser.hpp"
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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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const auto end = str.find_first_of(" \t\n\r");
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const auto sub = str.substr(0, end);
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if (sub.empty())
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return ParseStatus::Finished;
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if (state.pass != Pass::None) {
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switch (state.pass) {
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case Pass::Comment:
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if (str.front() == ')')
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state.pass = Pass::None;
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str = str.substr(1);
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break;
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case Pass::Colon:
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state.pass = Pass::None;
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state.compiling = true;
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state.dict.addDefinition(sub);
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break;
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case Pass::Constant:
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state.pass = Pass::None;
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state.compiling = true;
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state.dict.addDefinition(sub);
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state.dict.add(CoreWords::HiddenWordLiteral);
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state.dict.add(state.pop());
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state.dict.add(CoreWords::findi(";"));
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CoreWords::run(CoreWords::findi(";"), state);
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break;
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default:
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break;
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}
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} else {
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if (auto i = CoreWords::findi(sub); i >= 0) {
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if (state.compiling)
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state.dict.add(i);
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if (!state.compiling || sub.front() == ';')
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CoreWords::run(i, state);
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} else if (auto j = state.dict.find(sub); 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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Executor::fullexec(state, 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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Executor::fullexec(state, e);
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}
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} else {
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char *p;
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const auto l = static_cast<Cell>(std::strtol(sub.data(), &p, 10));
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if (p != sub.data()) {
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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::Error;
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}
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}
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if (end == std::string_view::npos)
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return ParseStatus::Finished;
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}
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const auto next = str.find_first_not_of(" \t\n\r", end);
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if (next == std::string_view::npos) {
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return ParseStatus::Finished;
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} else {
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str = str.substr(next);
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return ParseStatus::Continue;
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}
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}
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