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#include "Python.h"
#include "Python-ast.h"
#include "node.h"
#include "token.h"
#include "graminit.h"
#include "code.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 *"
static int
future_check_features(PyFutureFeatures *ff, stmt_ty s, const char *filename)
{
int i;
const char *feature;
asdl_seq *names;
assert(s->kind == ImportFrom_kind);
names = s->v.ImportFrom.names;
for (i = 0; i < asdl_seq_LEN(names); i++) {
alias_ty name = asdl_seq_GET(names, i);
feature = PyString_AsString(name->name);
if (!feature)
return 0;
if (strcmp(feature, FUTURE_NESTED_SCOPES) == 0) {
continue;
} else if (strcmp(feature, FUTURE_GENERATORS) == 0) {
continue;
} else if (strcmp(feature, FUTURE_DIVISION) == 0) {
ff->ff_features |= CO_FUTURE_DIVISION;
} else if (strcmp(feature, "braces") == 0) {
PyErr_SetString(PyExc_SyntaxError,
"not a chance");
PyErr_SyntaxLocation(filename, s->lineno);
return 0;
} else {
PyErr_Format(PyExc_SyntaxError,
UNDEFINED_FUTURE_FEATURE, feature);
PyErr_SyntaxLocation(filename, s->lineno);
return 0;
}
}
return 1;
}
static int
future_parse(PyFutureFeatures *ff, mod_ty mod, const char *filename)
{
int i, found_docstring = 0, done = 0, prev_line = 0;
static PyObject *future;
if (!future) {
future = PyString_InternFromString("__future__");
if (!future)
return 0;
}
if (!(mod->kind == Module_kind || mod->kind == Interactive_kind))
return 1;
/* A subsequent pass will detect future imports that don't
appear at the beginning of the file. There's one case,
however, that is easier to handl here: A series of imports
joined by semi-colons, where the first import is a future
statement but some subsequent import has the future form
but is preceded by a regular import.
*/
for (i = 0; i < asdl_seq_LEN(mod->v.Module.body); i++) {
stmt_ty s = asdl_seq_GET(mod->v.Module.body, i);
if (done && s->lineno > prev_line)
return 1;
prev_line = s->lineno;
/* The tests below will return from this function unless it is
still possible to find a future statement. The only things
that can precede a future statement are another future
statement and a doc string.
*/
if (s->kind == ImportFrom_kind) {
if (s->v.ImportFrom.module == future) {
if (done) {
PyErr_SetString(PyExc_SyntaxError,
ERR_LATE_FUTURE);
PyErr_SyntaxLocation(filename,
s->lineno);
return 0;
}
if (!future_check_features(ff, s, filename))
return 0;
ff->ff_lineno = s->lineno;
}
else
done = 1;
}
else if (s->kind == Expr_kind && !found_docstring) {
expr_ty e = s->v.Expr.value;
if (e->kind != Str_kind)
done = 1;
else
found_docstring = 1;
}
else
done = 1;
}
return 1;
}
PyFutureFeatures *
PyFuture_FromAST(mod_ty mod, const char *filename)
{
PyFutureFeatures *ff;
ff = (PyFutureFeatures *)PyMem_Malloc(sizeof(PyFutureFeatures));
if (ff == NULL)
return NULL;
ff->ff_features = 0;
ff->ff_lineno = -1;
if (!future_parse(ff, mod, filename)) {
PyMem_Free((void *)ff);
return NULL;
}
return ff;
}
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