mirror of https://github.com/python/cpython.git
137 lines
4.3 KiB
C
137 lines
4.3 KiB
C
#include "Python.h"
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#include "pycore_ast.h" // _PyAST_GetDocString()
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#define UNDEFINED_FUTURE_FEATURE "future feature %.100s is not defined"
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#define ERR_LATE_FUTURE \
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"from __future__ imports must occur at the beginning of the file"
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static int
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future_check_features(PyFutureFeatures *ff, stmt_ty s, PyObject *filename)
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{
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int i;
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assert(s->kind == ImportFrom_kind);
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asdl_alias_seq *names = s->v.ImportFrom.names;
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for (i = 0; i < asdl_seq_LEN(names); i++) {
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alias_ty name = (alias_ty)asdl_seq_GET(names, i);
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const char *feature = PyUnicode_AsUTF8(name->name);
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if (!feature)
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return 0;
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if (strcmp(feature, FUTURE_NESTED_SCOPES) == 0) {
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continue;
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} else if (strcmp(feature, FUTURE_GENERATORS) == 0) {
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continue;
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} else if (strcmp(feature, FUTURE_DIVISION) == 0) {
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continue;
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} else if (strcmp(feature, FUTURE_ABSOLUTE_IMPORT) == 0) {
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continue;
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} else if (strcmp(feature, FUTURE_WITH_STATEMENT) == 0) {
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continue;
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} else if (strcmp(feature, FUTURE_PRINT_FUNCTION) == 0) {
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continue;
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} else if (strcmp(feature, FUTURE_UNICODE_LITERALS) == 0) {
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continue;
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} else if (strcmp(feature, FUTURE_BARRY_AS_BDFL) == 0) {
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ff->ff_features |= CO_FUTURE_BARRY_AS_BDFL;
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} else if (strcmp(feature, FUTURE_GENERATOR_STOP) == 0) {
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continue;
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} else if (strcmp(feature, FUTURE_ANNOTATIONS) == 0) {
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ff->ff_features |= CO_FUTURE_ANNOTATIONS;
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} else if (strcmp(feature, "braces") == 0) {
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PyErr_SetString(PyExc_SyntaxError,
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"not a chance");
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PyErr_SyntaxLocationObject(filename, s->lineno, s->col_offset + 1);
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return 0;
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} else {
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PyErr_Format(PyExc_SyntaxError,
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UNDEFINED_FUTURE_FEATURE, feature);
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PyErr_SyntaxLocationObject(filename, s->lineno, s->col_offset + 1);
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return 0;
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}
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}
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return 1;
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}
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static int
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future_parse(PyFutureFeatures *ff, mod_ty mod, PyObject *filename)
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{
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int i, done = 0, prev_line = 0;
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if (!(mod->kind == Module_kind || mod->kind == Interactive_kind))
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return 1;
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if (asdl_seq_LEN(mod->v.Module.body) == 0)
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return 1;
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/* A subsequent pass will detect future imports that don't
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appear at the beginning of the file. There's one case,
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however, that is easier to handle here: A series of imports
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joined by semi-colons, where the first import is a future
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statement but some subsequent import has the future form
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but is preceded by a regular import.
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*/
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i = 0;
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if (_PyAST_GetDocString(mod->v.Module.body) != NULL)
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i++;
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for (; i < asdl_seq_LEN(mod->v.Module.body); i++) {
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stmt_ty s = (stmt_ty)asdl_seq_GET(mod->v.Module.body, i);
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if (done && s->lineno > prev_line)
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return 1;
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prev_line = s->lineno;
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/* The tests below will return from this function unless it is
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still possible to find a future statement. The only things
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that can precede a future statement are another future
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statement and a doc string.
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*/
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if (s->kind == ImportFrom_kind) {
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identifier modname = s->v.ImportFrom.module;
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if (modname &&
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_PyUnicode_EqualToASCIIString(modname, "__future__")) {
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if (done) {
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PyErr_SetString(PyExc_SyntaxError,
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ERR_LATE_FUTURE);
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PyErr_SyntaxLocationObject(filename, s->lineno, s->col_offset);
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return 0;
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}
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if (!future_check_features(ff, s, filename))
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return 0;
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ff->ff_lineno = s->lineno;
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}
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else {
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done = 1;
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}
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}
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else {
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done = 1;
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}
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}
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return 1;
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}
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PyFutureFeatures *
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_PyFuture_FromAST(mod_ty mod, PyObject *filename)
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{
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PyFutureFeatures *ff;
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ff = (PyFutureFeatures *)PyObject_Malloc(sizeof(PyFutureFeatures));
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if (ff == NULL) {
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PyErr_NoMemory();
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return NULL;
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}
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ff->ff_features = 0;
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ff->ff_lineno = -1;
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if (!future_parse(ff, mod, filename)) {
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PyObject_Free(ff);
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return NULL;
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}
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return ff;
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}
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