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113 lines
3.0 KiB
C++
113 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 <charconv>
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#include <cstring>
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int Parser::parse(State& state, const char *str)
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{
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auto addr = Dictionary::Input;
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state.dict.write(addr, 0);
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state.dict.write(Dictionary::SourceLen, std::strlen(str));
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addr += sizeof(Cell);
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while (*str)
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state.dict.writebyte(addr++, *str++);
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while (addr < Dictionary::Input + Dictionary::InputCells)
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state.dict.writebyte(addr++, '\0');
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return parseSource(state);
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}
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int 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)
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return ret;
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word = state.dict.input();
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}
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return 0;
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}
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int Parser::parseWord(State& state, Word word)
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{
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int ins, imm;
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ins = state.dict.find(word);
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if (ins <= 0) {
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ins = CoreWords::findi(state, word);
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if (ins < 0)
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return parseNumber(state, word);
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else
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imm = ins == CoreWords::Semicolon;
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} else {
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imm = state.dict.read(ins) & CoreWords::Immediate;
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ins = state.dict.getexec(ins);
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}
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if (state.compiling() && !imm)
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state.dict.add(ins);
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else if (auto stat = state.execute(ins); stat != State::Error::none)
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return static_cast<int>(stat);
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return 0;
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}
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int Parser::parseNumber(State& state, Word word)
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{
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char buf[MaxCellNumberChars + 1];
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unsigned i;
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for (i = 0; i < std::min(MaxCellNumberChars, word.size()); ++i)
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buf[i] = state.dict.readbyte(word.start + i);
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buf[i] = '\0';
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auto base = state.dict.read(0);
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DoubleCell dl;
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auto [ptr, ec] = std::from_chars(buf, buf + i, dl, base);
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Cell l = static_cast<Cell>(dl);
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if (ec == std::errc() && ptr == buf + i) {
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if (state.compiling()) {
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auto ins = CoreWords::findi("_lit");
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//if (l >= 0 && l < 0xFF) {
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// state.dict.add(ins | ((l + 1) << 8));
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//} else {
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state.dict.add(ins);
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state.dict.add(l);
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//}
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} else {
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state.push(l);
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}
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return 0;
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} else {
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return UnknownWord;
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}
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}
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