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
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
|
#include "Python.h"
#include "node.h"
#include "token.h"
#include "graminit.h"
#include "compile.h"
#include "symtable.h"
#define UNDEFINED_FUTURE_FEATURE "future feature %.100s is not defined"
#define FUTURE_IMPORT_STAR "future statement does not support import *"
#define FUTURE_POSSIBLE(FF) ((FF)->ff_last_lineno == -1)
static int
future_check_features(PyFutureFeatures *ff, node *n, char *filename)
{
int i;
char *feature;
node *ch;
REQ(n, import_stmt); /* must by from __future__ import ... */
for (i = 3; i < NCH(n); ++i) {
ch = CHILD(n, i);
if (TYPE(ch) == STAR) {
PyErr_SetString(PyExc_SyntaxError,
FUTURE_IMPORT_STAR);
PyErr_SyntaxLocation(filename, ch->n_lineno);
return -1;
}
REQ(ch, import_as_name);
feature = STR(CHILD(ch, 0));
if (strcmp(feature, FUTURE_NESTED_SCOPES) == 0) {
ff->ff_nested_scopes = 1;
} else if (strcmp(feature, "braces") == 0) {
PyErr_SetString(PyExc_SyntaxError,
"not a chance");
PyErr_SyntaxLocation(filename, CHILD(ch, 0)->n_lineno);
return -1;
} else {
PyErr_Format(PyExc_SyntaxError,
UNDEFINED_FUTURE_FEATURE, feature);
PyErr_SyntaxLocation(filename, CHILD(ch, 0)->n_lineno);
return -1;
}
}
return 0;
}
static void
future_error(node *n, char *filename)
{
PyErr_SetString(PyExc_SyntaxError,
"from __future__ imports must occur at the "
"beginning of the file");
PyErr_SyntaxLocation(filename, n->n_lineno);
/* XXX set filename and lineno */
}
/* Relevant portions of the grammar:
single_input: NEWLINE | simple_stmt | compound_stmt NEWLINE
file_input: (NEWLINE | stmt)* ENDMARKER
stmt: simple_stmt | compound_stmt
simple_stmt: small_stmt (';' small_stmt)* [';'] NEWLINE
small_stmt: expr_stmt | print_stmt | del_stmt | pass_stmt | flow_stmt
| import_stmt | global_stmt | exec_stmt | assert_stmt
import_stmt: 'import' dotted_as_name (',' dotted_as_name)*
| 'from' dotted_name 'import' ('*' | import_as_name (',' import_as_name)*)
import_as_name: NAME [NAME NAME]
dotted_as_name: dotted_name [NAME NAME]
dotted_name: NAME ('.' NAME)*
*/
/* future_parse() return values:
-1 indicates an error occurred, e.g. unknown feature name
0 indicates no feature was found
1 indicates a feature was found
*/
static int
future_parse(PyFutureFeatures *ff, node *n, char *filename)
{
int i, r;
loop:
switch (TYPE(n)) {
case single_input:
if (TYPE(CHILD(n, 0)) == simple_stmt) {
n = CHILD(n, 0);
goto loop;
}
return 0;
case file_input:
for (i = 0; i < NCH(n); i++) {
node *ch = CHILD(n, i);
if (TYPE(ch) == stmt) {
r = future_parse(ff, ch, filename);
if (!FUTURE_POSSIBLE(ff))
return r;
}
}
return 0;
case simple_stmt:
if (NCH(n) == 2) {
REQ(CHILD(n, 0), small_stmt);
n = CHILD(n, 0);
goto loop;
} else {
/* Deal with the special case of a series of
small statements on a single line. If a
future statement follows some other
statement, the SyntaxError is raised here.
In all other cases, the symtable pass
raises the exception.
*/
int found = 0, end_of_future = 0;
for (i = 0; i < NCH(n); i += 2) {
if (TYPE(CHILD(n, i)) == small_stmt) {
r = future_parse(ff, CHILD(n, i),
filename);
if (r < 1)
end_of_future = 1;
else {
found = 1;
if (end_of_future) {
future_error(n,
filename);
return -1;
}
}
}
}
/* If we found one and only one, then the
current lineno is legal.
*/
if (found)
ff->ff_last_lineno = n->n_lineno + 1;
else
ff->ff_last_lineno = n->n_lineno;
if (end_of_future && found)
return 1;
else
return 0;
}
case stmt:
if (TYPE(CHILD(n, 0)) == simple_stmt) {
n = CHILD(n, 0);
goto loop;
} else if (TYPE(CHILD(n, 0)) == expr_stmt) {
n = CHILD(n, 0);
goto loop;
} else {
REQ(CHILD(n, 0), compound_stmt);
ff->ff_last_lineno = n->n_lineno;
return 0;
}
case small_stmt:
n = CHILD(n, 0);
goto loop;
case import_stmt: {
node *name;
if (STR(CHILD(n, 0))[0] != 'f') { /* from */
ff->ff_last_lineno = n->n_lineno;
return 0;
}
name = CHILD(n, 1);
if (strcmp(STR(CHILD(name, 0)), "__future__") != 0)
return 0;
if (future_check_features(ff, n, filename) < 0)
return -1;
ff->ff_last_lineno = n->n_lineno + 1;
return 1;
}
/* The cases below -- all of them! -- are necessary to find
and skip doc strings. */
case expr_stmt:
case testlist:
case test:
case and_test:
case not_test:
case comparison:
case expr:
case xor_expr:
case and_expr:
case shift_expr:
case arith_expr:
case term:
case factor:
case power:
if (NCH(n) == 1) {
n = CHILD(n, 0);
goto loop;
}
break;
case atom:
if (TYPE(CHILD(n, 0)) == STRING
&& ff->ff_found_docstring == 0) {
ff->ff_found_docstring = 1;
return 0;
}
ff->ff_last_lineno = n->n_lineno;
return 0;
default:
ff->ff_last_lineno = n->n_lineno;
return 0;
}
return 0;
}
PyFutureFeatures *
PyNode_Future(node *n, char *filename)
{
PyFutureFeatures *ff;
ff = (PyFutureFeatures *)PyMem_Malloc(sizeof(PyFutureFeatures));
if (ff == NULL)
return NULL;
ff->ff_found_docstring = 0;
ff->ff_last_lineno = -1;
ff->ff_nested_scopes = 0;
if (future_parse(ff, n, filename) < 0) {
PyMem_Free((void *)ff);
return NULL;
}
return ff;
}
|
