#include "Python.h"

#include "pycore_ast.h" // _PyAST_GetDocString()

#define UNDEFINED_FUTURE_FEATURE "future feature %.100s is not defined"

#define ERR_LATE_FUTURE \

"from __future__ imports must occur at the beginning of the file"

static int

future_check_features(PyFutureFeatures *ff, stmt_ty s, PyObject *filename)

{

int i;

assert(s->kind == ImportFrom_kind);

asdl_alias_seq *names = s->v.ImportFrom.names;

for (i = 0; i < asdl_seq_LEN(names); i++) {

alias_ty name = (alias_ty)asdl_seq_GET(names, i);

const char *feature = PyUnicode_AsUTF8(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) {

continue;

} else if (strcmp(feature, FUTURE_ABSOLUTE_IMPORT) == 0) {

continue;

} else if (strcmp(feature, FUTURE_WITH_STATEMENT) == 0) {

continue;

} else if (strcmp(feature, FUTURE_PRINT_FUNCTION) == 0) {

continue;

} else if (strcmp(feature, FUTURE_UNICODE_LITERALS) == 0) {

continue;

} else if (strcmp(feature, FUTURE_BARRY_AS_BDFL) == 0) {

ff->ff_features |= CO_FUTURE_BARRY_AS_BDFL;

} else if (strcmp(feature, FUTURE_GENERATOR_STOP) == 0) {

continue;

} else if (strcmp(feature, FUTURE_ANNOTATIONS) == 0) {

ff->ff_features |= CO_FUTURE_ANNOTATIONS;

} else if (strcmp(feature, "braces") == 0) {

PyErr_SetString(PyExc_SyntaxError,

"not a chance");

PyErr_SyntaxLocationObject(filename, s->lineno, s->col_offset + 1);

return 0;

} else {

PyErr_Format(PyExc_SyntaxError,

UNDEFINED_FUTURE_FEATURE, feature);

PyErr_SyntaxLocationObject(filename, s->lineno, s->col_offset + 1);

return 0;

}

}

return 1;

}

static int

future_parse(PyFutureFeatures *ff, mod_ty mod, PyObject *filename)

{

int i, done = 0, prev_line = 0;

if (!(mod->kind == Module_kind || mod->kind == Interactive_kind))

return 1;

if (asdl_seq_LEN(mod->v.Module.body) == 0)

return 1;

/* A subsequent pass will detect future imports that don't

i = 0;

if (_PyAST_GetDocString(mod->v.Module.body) != NULL)

i++;

for (; i < asdl_seq_LEN(mod->v.Module.body); i++) {

stmt_ty s = (stmt_ty)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

if (s->kind == ImportFrom_kind) {

identifier modname = s->v.ImportFrom.module;

if (modname &&

_PyUnicode_EqualToASCIIString(modname, "__future__")) {

if (done) {

PyErr_SetString(PyExc_SyntaxError,

ERR_LATE_FUTURE);

PyErr_SyntaxLocationObject(filename, s->lineno, s->col_offset);

return 0;

}

if (!future_check_features(ff, s, filename))

return 0;

ff->ff_lineno = s->lineno;

}

else {

done = 1;

}

}

else {

done = 1;

}

}

return 1;

}

PyFutureFeatures *

_PyFuture_FromAST(mod_ty mod, PyObject *filename)

{

PyFutureFeatures *ff;

ff = (PyFutureFeatures *)PyObject_Malloc(sizeof(PyFutureFeatures));

if (ff == NULL) {

PyErr_NoMemory();

return NULL;

}

ff->ff_features = 0;

ff->ff_lineno = -1;

if (!future_parse(ff, mod, filename)) {

PyObject_Free(ff);

return NULL;

}

return ff;

}