Line data Source code
1 : #include "Python.h"
2 : #include "Python-ast.h"
3 : #include "node.h"
4 : #include "token.h"
5 : #include "graminit.h"
6 : #include "code.h"
7 : #include "compile.h"
8 : #include "symtable.h"
9 :
10 : #define UNDEFINED_FUTURE_FEATURE "future feature %.100s is not defined"
11 : #define ERR_LATE_FUTURE \
12 : "from __future__ imports must occur at the beginning of the file"
13 :
14 : static int
15 12 : future_check_features(PyFutureFeatures *ff, stmt_ty s, const char *filename)
16 : {
17 : int i;
18 : asdl_seq *names;
19 :
20 : assert(s->kind == ImportFrom_kind);
21 :
22 12 : names = s->v.ImportFrom.names;
23 24 : for (i = 0; i < asdl_seq_LEN(names); i++) {
24 12 : alias_ty name = (alias_ty)asdl_seq_GET(names, i);
25 12 : const char *feature = PyString_AsString(name->name);
26 12 : if (!feature)
27 0 : return 0;
28 12 : if (strcmp(feature, FUTURE_NESTED_SCOPES) == 0) {
29 0 : continue;
30 12 : } else if (strcmp(feature, FUTURE_GENERATORS) == 0) {
31 0 : continue;
32 12 : } else if (strcmp(feature, FUTURE_DIVISION) == 0) {
33 0 : ff->ff_features |= CO_FUTURE_DIVISION;
34 12 : } else if (strcmp(feature, FUTURE_ABSOLUTE_IMPORT) == 0) {
35 0 : ff->ff_features |= CO_FUTURE_ABSOLUTE_IMPORT;
36 12 : } else if (strcmp(feature, FUTURE_WITH_STATEMENT) == 0) {
37 0 : ff->ff_features |= CO_FUTURE_WITH_STATEMENT;
38 12 : } else if (strcmp(feature, FUTURE_PRINT_FUNCTION) == 0) {
39 12 : ff->ff_features |= CO_FUTURE_PRINT_FUNCTION;
40 0 : } else if (strcmp(feature, FUTURE_UNICODE_LITERALS) == 0) {
41 0 : ff->ff_features |= CO_FUTURE_UNICODE_LITERALS;
42 0 : } else if (strcmp(feature, "braces") == 0) {
43 0 : PyErr_SetString(PyExc_SyntaxError,
44 : "not a chance");
45 0 : PyErr_SyntaxLocation(filename, s->lineno);
46 0 : return 0;
47 : } else {
48 0 : PyErr_Format(PyExc_SyntaxError,
49 : UNDEFINED_FUTURE_FEATURE, feature);
50 0 : PyErr_SyntaxLocation(filename, s->lineno);
51 0 : return 0;
52 : }
53 : }
54 12 : return 1;
55 : }
56 :
57 : static int
58 63 : future_parse(PyFutureFeatures *ff, mod_ty mod, const char *filename)
59 : {
60 63 : int i, found_docstring = 0, done = 0, prev_line = 0;
61 :
62 63 : if (!(mod->kind == Module_kind || mod->kind == Interactive_kind))
63 0 : return 1;
64 :
65 : /* A subsequent pass will detect future imports that don't
66 : appear at the beginning of the file. There's one case,
67 : however, that is easier to handle here: A series of imports
68 : joined by semi-colons, where the first import is a future
69 : statement but some subsequent import has the future form
70 : but is preceded by a regular import.
71 : */
72 :
73 :
74 167 : for (i = 0; i < asdl_seq_LEN(mod->v.Module.body); i++) {
75 137 : stmt_ty s = (stmt_ty)asdl_seq_GET(mod->v.Module.body, i);
76 :
77 137 : if (done && s->lineno > prev_line)
78 33 : return 1;
79 104 : prev_line = s->lineno;
80 :
81 : /* The tests below will return from this function unless it is
82 : still possible to find a future statement. The only things
83 : that can precede a future statement are another future
84 : statement and a doc string.
85 : */
86 :
87 104 : if (s->kind == ImportFrom_kind) {
88 18 : identifier modname = s->v.ImportFrom.module;
89 30 : if (modname && PyString_GET_SIZE(modname) == 10 &&
90 12 : !strcmp(PyString_AS_STRING(modname), "__future__")) {
91 12 : if (done) {
92 0 : PyErr_SetString(PyExc_SyntaxError,
93 : ERR_LATE_FUTURE);
94 0 : PyErr_SyntaxLocation(filename,
95 : s->lineno);
96 0 : return 0;
97 : }
98 12 : if (!future_check_features(ff, s, filename))
99 0 : return 0;
100 12 : ff->ff_lineno = s->lineno;
101 : }
102 : else
103 6 : done = 1;
104 : }
105 118 : else if (s->kind == Expr_kind && !found_docstring) {
106 32 : expr_ty e = s->v.Expr.value;
107 32 : if (e->kind != Str_kind)
108 0 : done = 1;
109 : else
110 32 : found_docstring = 1;
111 : }
112 : else
113 54 : done = 1;
114 : }
115 30 : return 1;
116 : }
117 :
118 :
119 : PyFutureFeatures *
120 63 : PyFuture_FromAST(mod_ty mod, const char *filename)
121 : {
122 : PyFutureFeatures *ff;
123 :
124 63 : ff = (PyFutureFeatures *)PyObject_Malloc(sizeof(PyFutureFeatures));
125 63 : if (ff == NULL) {
126 0 : PyErr_NoMemory();
127 0 : return NULL;
128 : }
129 63 : ff->ff_features = 0;
130 63 : ff->ff_lineno = -1;
131 :
132 63 : if (!future_parse(ff, mod, filename)) {
133 0 : PyObject_Free(ff);
134 0 : return NULL;
135 : }
136 63 : return ff;
137 : }
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