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