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
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
|
/* -*- c++ -*- */
/*
* Copyright © 2010 Intel Corporation
*
* Permission is hereby granted, free of charge, to any person obtaining a
* copy of this software and associated documentation files (the "Software"),
* to deal in the Software without restriction, including without limitation
* the rights to use, copy, modify, merge, publish, distribute, sublicense,
* and/or sell copies of the Software, and to permit persons to whom the
* Software is furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice (including the next
* paragraph) shall be included in all copies or substantial portions of the
* Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
* DEALINGS IN THE SOFTWARE.
*/
#include <assert.h>
#include <limits>
#include "s_expression.h"
s_symbol::s_symbol(const char *str, size_t n)
{
/* Assume the given string is already nul-terminated and in memory that
* will live as long as this node.
*/
assert(str[n] == '\0');
this->str = str;
}
s_list::s_list()
{
}
static void
skip_whitespace(const char *&src, char *&symbol_buffer)
{
size_t n = strspn(src, " \v\t\r\n");
src += n;
symbol_buffer += n;
/* Also skip Scheme-style comments: semi-colon 'til end of line */
if (src[0] == ';') {
n = strcspn(src, "\n");
src += n;
symbol_buffer += n;
skip_whitespace(src, symbol_buffer);
}
}
static s_expression *
read_atom(void *ctx, const char *&src, char *&symbol_buffer)
{
s_expression *expr = NULL;
skip_whitespace(src, symbol_buffer);
size_t n = strcspn(src, "( \v\t\r\n);");
if (n == 0)
return NULL; // no atom
// Check for the special symbol '+INF', which means +Infinity. Note: C99
// requires strtof to parse '+INF' as +Infinity, but we still support some
// non-C99-compliant compilers (e.g. MSVC).
if (n == 4 && strncmp(src, "+INF", 4) == 0) {
expr = new(ctx) s_float(std::numeric_limits<float>::infinity());
} else {
// Check if the atom is a number.
char *float_end = NULL;
float f = glsl_strtof(src, &float_end);
if (float_end != src) {
char *int_end = NULL;
int i = strtol(src, &int_end, 10);
// If strtof matched more characters, it must have a decimal part
if (float_end > int_end)
expr = new(ctx) s_float(f);
else
expr = new(ctx) s_int(i);
} else {
// Not a number; return a symbol.
symbol_buffer[n] = '\0';
expr = new(ctx) s_symbol(symbol_buffer, n);
}
}
src += n;
symbol_buffer += n;
return expr;
}
static s_expression *
__read_expression(void *ctx, const char *&src, char *&symbol_buffer)
{
s_expression *atom = read_atom(ctx, src, symbol_buffer);
if (atom != NULL)
return atom;
skip_whitespace(src, symbol_buffer);
if (src[0] == '(') {
++src;
++symbol_buffer;
s_list *list = new(ctx) s_list;
s_expression *expr;
while ((expr = __read_expression(ctx, src, symbol_buffer)) != NULL) {
list->subexpressions.push_tail(expr);
}
skip_whitespace(src, symbol_buffer);
if (src[0] != ')') {
printf("Unclosed expression (check your parenthesis).\n");
return NULL;
}
++src;
++symbol_buffer;
return list;
}
return NULL;
}
s_expression *
s_expression::read_expression(void *ctx, const char *&src)
{
assert(src != NULL);
/* When we encounter a Symbol, we need to save a nul-terminated copy of
* the string. However, ralloc_strndup'ing every individual Symbol is
* extremely expensive. We could avoid this by simply overwriting the
* next character (guaranteed to be whitespace, parens, or semicolon) with
* a nul-byte. But overwriting non-whitespace would mess up parsing.
*
* So, just copy the whole buffer ahead of time. Walk both, leaving the
* original source string unmodified, and altering the copy to contain the
* necessary nul-bytes whenever we encounter a symbol.
*/
char *symbol_buffer = ralloc_strdup(ctx, src);
return __read_expression(ctx, src, symbol_buffer);
}
void s_int::print()
{
printf("%d", this->val);
}
void s_float::print()
{
printf("%f", this->val);
}
void s_symbol::print()
{
printf("%s", this->str);
}
void s_list::print()
{
printf("(");
foreach_list(n, &this->subexpressions) {
s_expression *expr = (s_expression *) n;
expr->print();
if (!expr->next->is_tail_sentinel())
printf(" ");
}
printf(")");
}
// --------------------------------------------------
bool
s_pattern::match(s_expression *expr)
{
switch (type)
{
case EXPR: *p_expr = expr; break;
case LIST: if (expr->is_list()) *p_list = (s_list *) expr; break;
case SYMBOL: if (expr->is_symbol()) *p_symbol = (s_symbol *) expr; break;
case NUMBER: if (expr->is_number()) *p_number = (s_number *) expr; break;
case INT: if (expr->is_int()) *p_int = (s_int *) expr; break;
case STRING:
s_symbol *sym = SX_AS_SYMBOL(expr);
if (sym != NULL && strcmp(sym->value(), literal) == 0)
return true;
return false;
};
return *p_expr == expr;
}
bool
s_match(s_expression *top, unsigned n, s_pattern *pattern, bool partial)
{
s_list *list = SX_AS_LIST(top);
if (list == NULL)
return false;
unsigned i = 0;
foreach_list(node, &list->subexpressions) {
if (i >= n)
return partial; /* More actual items than the pattern expected */
s_expression *expr = (s_expression *) node;
if (expr == NULL || !pattern[i].match(expr))
return false;
i++;
}
if (i < n)
return false; /* Less actual items than the pattern expected */
return true;
}
|
