1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
|
/**
* 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"
Error Parser::parse(State& state, const char *str)
{
auto addr = Dictionary::Input;
Cell len = 0;
for (auto ptr = str; *ptr; ++ptr)
++len;
state.dict.write(addr, 0);
state.dict.write(Dictionary::SourceLen, len);
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)
{
bool imm;
Addr ins = state.dict.find(word);
if (ins == 0) {
auto cw = CoreWords::findi(state, word);
if (cw < 0) {
return parseNumber(state, word);
} else {
ins = cw;
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 - (isupper(c) ? 'A' : 'a');
} else {
return Error::noword;
}
if (++i < word.wend)
c = state.dict.readbyte(i);
} while (i < word.wend);
if (inv)
result *= -1;
auto value = static_cast<Cell>(result);
if (state.compiling()) {
auto ins = CoreWords::findi("_lit");
const Cell maxlit = Dictionary::Begin - CoreWords::WordCount;
if (value >= 0 && value < maxlit) {
state.dict.add(value + CoreWords::WordCount);
} else {
state.dict.add(ins);
state.dict.add(value);
}
} else {
state.push(value);
}
return Error::none;
}
|
