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98 lines
2.6 KiB
C++
98 lines
2.6 KiB
C++
// sprit-forth: A portable subroutine-threaded Forth.
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// Copyright (C) 2024 Clyne Sullivan <clyne@bitgloo.com>
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//
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// This library is free software; you can redistribute it and/or modify it
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// under the terms of the GNU Library General Public License as published by
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// the Free Software Foundation; either version 2 of the License, or (at your
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// option) any later version.
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//
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// This library is distributed in the hope that it will be useful, but WITHOUT
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// ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
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// FOR A PARTICULAR PURPOSE. See the GNU Library General Public License for
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// more details.
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//
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// You should have received a copy of the GNU Library General Public License
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// along with this library; if not, write to the Free Software Foundation, Inc.,
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// 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA.
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#include "core.hpp"
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#include "executor.hpp"
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#include "state.hpp"
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#include "types.hpp"
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#include <cctype>
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#include <cstdlib>
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__attribute__((weak))
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int findword(const char *, int)
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{
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return -1;
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}
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[[nodiscard]]
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static Error parseword(const char *start, const char *end)
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{
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auto result = Error::none;
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if (start != end) {
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if (auto word = Forth.find(start, end - start); word) {
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if (!word->immediate() && Forth.state) {
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comma((Cell)word->list);
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} else {
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result = Exec.execute1(word);
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}
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} else if (isdigit(*start) || (*start == '-' && isdigit(*(start + 1)))) {
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Forth.push(std::atoi(start));
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if (Forth.state)
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compileliteral();
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} else if (findword(start, end - start)) {
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return Error::noword;
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}
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}
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return result;
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}
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[[nodiscard]]
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static Error parseSource()
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{
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auto result = Error::none;
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char *start = (char *)Forth.source;
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char *end = start;
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auto& i = *((char *)&Forth.sourcei);
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while (result == Error::none && i < Forth.sourceu) {
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if (isspace(*end) || *end == '\0') {
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if (end - start < 1) {
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start = ++end;
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++i;
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} else {
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++i; // discard the space
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result = parseword(start, end);
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start = (char *)Forth.source + i;
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end = start;
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}
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} else {
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++end;
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++i;
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}
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}
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return result;
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}
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[[nodiscard]]
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Error parse()
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{
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// Reset source buffer and try to fill it with getinput().
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Forth.source = (Cell)&Forth.sourcei + 1;
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Forth.sourceu = 0;
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Forth.sourcei = 0;
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getinput();
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addkey('\0');
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return parseSource();
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}
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