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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 "ctype.hpp"
#include "parser.hpp"
#include <cstring>
Error Parser::parse(State& state, const char *str)
{
auto addr = Dictionary::Input;
state.dict.write(addr, 0);
state.dict.write(Dictionary::SourceLen, std::strlen(str));
addr += sizeof(Cell);
while (*str)
state.dict.writebyte(addr++, *str++);
while (addr < Dictionary::Input + Dictionary::InputCells)
state.dict.writebyte(addr++, '\0');
return parseSource(state);
}
Error Parser::parseSource(State& state)
{
auto word = state.dict.input();
while (word.size() > 0) {
if (auto ret = parseWord(state, word); ret != Error::none)
return ret;
word = state.dict.input();
}
return Error::none;
}
Error 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::Semicolon;
} else {
imm = state.dict.read(ins) & Dictionary::Immediate;
ins = state.dict.getexec(ins);
}
if (state.compiling() && !imm)
state.dict.add(ins);
else if (auto stat = state.execute(ins); stat != Error::none)
return stat;
return Error::none;
}
Error Parser::parseNumber(State& state, Word word)
{
const auto base = state.dict.read(Dictionary::Base);
DoubleCell result = 0;
auto i = word.start;
bool inv;
char c;
c = state.dict.readbyte(i);
if (inv = c == '-'; inv)
c = state.dict.readbyte(++i);
do {
if (isdigit(c)) {
result *= base;
result += c - '0';
} else if (isalpha(c) && base > 10) {
result *= base;
result += 10 + (c > 'a' ? c - 'a' : c - 'A');
} else {
return Error::noword;
}
if (++i < word.wend)
c = state.dict.readbyte(i);
} while (i < word.wend);
if (inv)
result *= -1;
Cell value = static_cast<Cell>(result);
if (state.compiling()) {
auto ins = CoreWords::findi("_lit");
if (value >= 0 && value < static_cast<Cell>(Dictionary::Begin - CoreWords::WordCount)) {
state.dict.add(value + CoreWords::WordCount);
} else {
state.dict.add(ins);
state.dict.add(value);
}
} else {
state.push(value);
}
return Error::none;
}
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