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// sprit-forth: A portable subroutine-threaded Forth.
// Copyright (C) 2024 Clyne Sullivan <clyne@bitgloo.com>
//
// This library is free software; you can redistribute it and/or modify it
// under the terms of the GNU Library General Public License as published by
// the Free Software Foundation; either version 2 of the License, or (at your
// option) any later version.
//
// This library 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 Library General Public License for
// more details.
//
// You should have received a copy of the GNU Library General Public License
// along with this library; if not, write to the Free Software Foundation, Inc.,
// 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA.
#include "core.hpp"
#include "executor.hpp"
#include "state.hpp"
#include "types.hpp"
#include <cctype>
#include <cstdlib>
__attribute__((weak))
int findword(const char *, int)
{
return -1;
}
[[nodiscard]]
static Error parseword(const char *start, const char *end)
{
auto result = Error::none;
if (start != end) {
if (auto word = Forth.find(start, end - start); word) {
if (!word->immediate() && Forth.state) {
comma((Cell)word->list);
} else {
result = Exec.execute1(word);
}
} else if (isdigit(*start) || (*start == '-' && isdigit(*(start + 1)))) {
Forth.push(std::atoi(start));
if (Forth.state)
compileliteral();
} else if (findword(start, end - start)) {
return Error::noword;
}
}
return result;
}
[[nodiscard]]
static Error parseSource()
{
auto result = Error::none;
char *start = (char *)Forth.source;
char *end = start;
auto& i = *((char *)&Forth.sourcei);
while (result == Error::none && i < Forth.sourceu) {
if (isspace(*end) || *end == '\0') {
if (end - start < 1) {
start = ++end;
++i;
} else {
++i; // discard the space
result = parseword(start, end);
start = (char *)Forth.source + i;
end = start;
}
} else {
++end;
++i;
}
}
return result;
}
[[nodiscard]]
Error parse()
{
// Reset source buffer and try to fill it with getinput().
Forth.source = (Cell)&Forth.sourcei + 1;
Forth.sourceu = 0;
Forth.sourcei = 0;
getinput();
addkey('\0');
return parseSource();
}
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