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Jeremy Hylton4db62b12001-02-27 19:07:02 +00001#include "Python.h"
2#include "node.h"
3#include "token.h"
4#include "graminit.h"
5#include "compile.h"
6#include "symtable.h"
7
8#define UNDEFINED_FUTURE_FEATURE "future feature %.100s is not defined"
Jeremy Hyltonad3d3f22001-02-28 17:47:12 +00009#define FUTURE_IMPORT_STAR "future statement does not support import *"
Jeremy Hylton4db62b12001-02-27 19:07:02 +000010
Jeremy Hylton1e35ce52001-08-20 20:32:33 +000011/* FUTURE_POSSIBLE() is provided to accomodate doc strings, which is
12 the only statement that can occur before a future statement.
13*/
Jeremy Hylton39e2f3f2001-02-28 01:58:08 +000014#define FUTURE_POSSIBLE(FF) ((FF)->ff_last_lineno == -1)
15
Jeremy Hylton4db62b12001-02-27 19:07:02 +000016static int
Jeremy Hyltonad3d3f22001-02-28 17:47:12 +000017future_check_features(PyFutureFeatures *ff, node *n, char *filename)
Jeremy Hylton4db62b12001-02-27 19:07:02 +000018{
19 int i;
20 char *feature;
Jeremy Hyltonad3d3f22001-02-28 17:47:12 +000021 node *ch;
Jeremy Hylton4db62b12001-02-27 19:07:02 +000022
23 REQ(n, import_stmt); /* must by from __future__ import ... */
24
Fred Drake198457a2001-03-10 02:15:37 +000025 for (i = 3; i < NCH(n); i += 2) {
Jeremy Hyltonad3d3f22001-02-28 17:47:12 +000026 ch = CHILD(n, i);
27 if (TYPE(ch) == STAR) {
28 PyErr_SetString(PyExc_SyntaxError,
29 FUTURE_IMPORT_STAR);
30 PyErr_SyntaxLocation(filename, ch->n_lineno);
31 return -1;
32 }
33 REQ(ch, import_as_name);
34 feature = STR(CHILD(ch, 0));
Jeremy Hylton4db62b12001-02-27 19:07:02 +000035 if (strcmp(feature, FUTURE_NESTED_SCOPES) == 0) {
Jeremy Hyltonb857ba22001-08-10 21:41:33 +000036 continue;
Guido van Rossumb09f7ed2001-07-15 21:08:29 +000037 } else if (strcmp(feature, FUTURE_GENERATORS) == 0) {
Tim Peters2bbdba32002-04-12 01:20:10 +000038 continue;
Guido van Rossum4668b002001-08-08 05:00:18 +000039 } else if (strcmp(feature, FUTURE_DIVISION) == 0) {
Jeremy Hyltonb857ba22001-08-10 21:41:33 +000040 ff->ff_features |= CO_FUTURE_DIVISION;
Jeremy Hyltonad3d3f22001-02-28 17:47:12 +000041 } else if (strcmp(feature, "braces") == 0) {
42 PyErr_SetString(PyExc_SyntaxError,
43 "not a chance");
44 PyErr_SyntaxLocation(filename, CHILD(ch, 0)->n_lineno);
45 return -1;
Jeremy Hylton4db62b12001-02-27 19:07:02 +000046 } else {
47 PyErr_Format(PyExc_SyntaxError,
48 UNDEFINED_FUTURE_FEATURE, feature);
Jeremy Hyltonad3d3f22001-02-28 17:47:12 +000049 PyErr_SyntaxLocation(filename, CHILD(ch, 0)->n_lineno);
Jeremy Hylton4db62b12001-02-27 19:07:02 +000050 return -1;
51 }
52 }
53 return 0;
54}
55
Jeremy Hylton39e2f3f2001-02-28 01:58:08 +000056static void
57future_error(node *n, char *filename)
58{
59 PyErr_SetString(PyExc_SyntaxError,
60 "from __future__ imports must occur at the "
61 "beginning of the file");
Jeremy Hyltonad3d3f22001-02-28 17:47:12 +000062 PyErr_SyntaxLocation(filename, n->n_lineno);
Jeremy Hylton39e2f3f2001-02-28 01:58:08 +000063}
64
Jeremy Hylton4db62b12001-02-27 19:07:02 +000065/* Relevant portions of the grammar:
66
67single_input: NEWLINE | simple_stmt | compound_stmt NEWLINE
68file_input: (NEWLINE | stmt)* ENDMARKER
69stmt: simple_stmt | compound_stmt
70simple_stmt: small_stmt (';' small_stmt)* [';'] NEWLINE
Jeremy Hyltonad3d3f22001-02-28 17:47:12 +000071small_stmt: expr_stmt | print_stmt | del_stmt | pass_stmt | flow_stmt
72 | import_stmt | global_stmt | exec_stmt | assert_stmt
73import_stmt: 'import' dotted_as_name (',' dotted_as_name)*
74 | 'from' dotted_name 'import' ('*' | import_as_name (',' import_as_name)*)
Jeremy Hylton4db62b12001-02-27 19:07:02 +000075import_as_name: NAME [NAME NAME]
76dotted_as_name: dotted_name [NAME NAME]
77dotted_name: NAME ('.' NAME)*
78*/
79
Jeremy Hylton1e35ce52001-08-20 20:32:33 +000080/* future_parse() finds future statements at the beginnning of a
81 module. The function calls itself recursively, rather than
82 factoring out logic for different kinds of statements into
83 different routines.
84
85 Return values:
Jeremy Hylton4db62b12001-02-27 19:07:02 +000086 -1 indicates an error occurred, e.g. unknown feature name
87 0 indicates no feature was found
88 1 indicates a feature was found
89*/
90
91static int
Jeremy Hylton39e2f3f2001-02-28 01:58:08 +000092future_parse(PyFutureFeatures *ff, node *n, char *filename)
Jeremy Hylton4db62b12001-02-27 19:07:02 +000093{
Jeremy Hylton39e2f3f2001-02-28 01:58:08 +000094 int i, r;
Jeremy Hylton4db62b12001-02-27 19:07:02 +000095 loop:
96
Jeremy Hylton4db62b12001-02-27 19:07:02 +000097 switch (TYPE(n)) {
98
Jeremy Hylton280c81a2001-02-28 02:26:14 +000099 case single_input:
100 if (TYPE(CHILD(n, 0)) == simple_stmt) {
101 n = CHILD(n, 0);
102 goto loop;
103 }
104 return 0;
105
Jeremy Hylton4db62b12001-02-27 19:07:02 +0000106 case file_input:
Jeremy Hylton1e35ce52001-08-20 20:32:33 +0000107 /* Check each statement in the file, starting with the
108 first, and continuing until the first statement
109 that isn't a future statement.
110 */
Jeremy Hylton4db62b12001-02-27 19:07:02 +0000111 for (i = 0; i < NCH(n); i++) {
112 node *ch = CHILD(n, i);
113 if (TYPE(ch) == stmt) {
Jeremy Hylton39e2f3f2001-02-28 01:58:08 +0000114 r = future_parse(ff, ch, filename);
Jeremy Hylton1e35ce52001-08-20 20:32:33 +0000115 /* Need to check both conditions below
116 to accomodate doc strings, which
117 causes r < 0.
118 */
119 if (r < 1 && !FUTURE_POSSIBLE(ff))
Jeremy Hylton39e2f3f2001-02-28 01:58:08 +0000120 return r;
Jeremy Hylton4db62b12001-02-27 19:07:02 +0000121 }
122 }
123 return 0;
124
125 case simple_stmt:
Jeremy Hylton39e2f3f2001-02-28 01:58:08 +0000126 if (NCH(n) == 2) {
Jeremy Hylton4db62b12001-02-27 19:07:02 +0000127 REQ(CHILD(n, 0), small_stmt);
128 n = CHILD(n, 0);
129 goto loop;
Jeremy Hylton39e2f3f2001-02-28 01:58:08 +0000130 } else {
131 /* Deal with the special case of a series of
132 small statements on a single line. If a
133 future statement follows some other
134 statement, the SyntaxError is raised here.
135 In all other cases, the symtable pass
136 raises the exception.
137 */
138 int found = 0, end_of_future = 0;
139
140 for (i = 0; i < NCH(n); i += 2) {
141 if (TYPE(CHILD(n, i)) == small_stmt) {
142 r = future_parse(ff, CHILD(n, i),
143 filename);
144 if (r < 1)
145 end_of_future = 1;
146 else {
147 found = 1;
148 if (end_of_future) {
149 future_error(n,
150 filename);
151 return -1;
152 }
153 }
154 }
Jeremy Hylton4db62b12001-02-27 19:07:02 +0000155 }
Jeremy Hylton39e2f3f2001-02-28 01:58:08 +0000156
157 /* If we found one and only one, then the
158 current lineno is legal.
159 */
160 if (found)
161 ff->ff_last_lineno = n->n_lineno + 1;
162 else
163 ff->ff_last_lineno = n->n_lineno;
164
165 if (end_of_future && found)
166 return 1;
167 else
168 return 0;
169 }
Jeremy Hylton4db62b12001-02-27 19:07:02 +0000170
171 case stmt:
172 if (TYPE(CHILD(n, 0)) == simple_stmt) {
173 n = CHILD(n, 0);
174 goto loop;
Jeremy Hylton39e2f3f2001-02-28 01:58:08 +0000175 } else if (TYPE(CHILD(n, 0)) == expr_stmt) {
176 n = CHILD(n, 0);
177 goto loop;
Jeremy Hylton4db62b12001-02-27 19:07:02 +0000178 } else {
179 REQ(CHILD(n, 0), compound_stmt);
180 ff->ff_last_lineno = n->n_lineno;
181 return 0;
182 }
183
184 case small_stmt:
185 n = CHILD(n, 0);
186 goto loop;
187
188 case import_stmt: {
189 node *name;
190
191 if (STR(CHILD(n, 0))[0] != 'f') { /* from */
192 ff->ff_last_lineno = n->n_lineno;
193 return 0;
194 }
195 name = CHILD(n, 1);
196 if (strcmp(STR(CHILD(name, 0)), "__future__") != 0)
197 return 0;
Jeremy Hyltonad3d3f22001-02-28 17:47:12 +0000198 if (future_check_features(ff, n, filename) < 0)
Jeremy Hylton4db62b12001-02-27 19:07:02 +0000199 return -1;
Jeremy Hylton280c81a2001-02-28 02:26:14 +0000200 ff->ff_last_lineno = n->n_lineno + 1;
Jeremy Hylton4db62b12001-02-27 19:07:02 +0000201 return 1;
202 }
203
Jeremy Hylton39e2f3f2001-02-28 01:58:08 +0000204 /* The cases below -- all of them! -- are necessary to find
205 and skip doc strings. */
206 case expr_stmt:
207 case testlist:
208 case test:
209 case and_test:
210 case not_test:
211 case comparison:
212 case expr:
213 case xor_expr:
214 case and_expr:
215 case shift_expr:
216 case arith_expr:
217 case term:
218 case factor:
219 case power:
220 if (NCH(n) == 1) {
221 n = CHILD(n, 0);
222 goto loop;
223 }
224 break;
225
226 case atom:
227 if (TYPE(CHILD(n, 0)) == STRING
228 && ff->ff_found_docstring == 0) {
229 ff->ff_found_docstring = 1;
230 return 0;
231 }
232 ff->ff_last_lineno = n->n_lineno;
233 return 0;
234
Jeremy Hylton4db62b12001-02-27 19:07:02 +0000235 default:
236 ff->ff_last_lineno = n->n_lineno;
237 return 0;
238 }
Jeremy Hylton39e2f3f2001-02-28 01:58:08 +0000239 return 0;
Jeremy Hylton4db62b12001-02-27 19:07:02 +0000240}
241
242PyFutureFeatures *
243PyNode_Future(node *n, char *filename)
244{
245 PyFutureFeatures *ff;
246
247 ff = (PyFutureFeatures *)PyMem_Malloc(sizeof(PyFutureFeatures));
248 if (ff == NULL)
249 return NULL;
Jeremy Hylton39e2f3f2001-02-28 01:58:08 +0000250 ff->ff_found_docstring = 0;
251 ff->ff_last_lineno = -1;
Jeremy Hyltonb857ba22001-08-10 21:41:33 +0000252 ff->ff_features = 0;
Jeremy Hylton4db62b12001-02-27 19:07:02 +0000253
Jeremy Hylton39e2f3f2001-02-28 01:58:08 +0000254 if (future_parse(ff, n, filename) < 0) {
Jeremy Hylton4db62b12001-02-27 19:07:02 +0000255 PyMem_Free((void *)ff);
256 return NULL;
257 }
258 return ff;
259}
260