mirror of
https://github.com/python/cpython
synced 2024-09-05 00:05:39 +00:00
![Guido van Rossum](/assets/img/avatar_default.png)
This adds a `feature_version` flag to `ast.parse()` (documented) and `compile()` (hidden) that allow tweaking the parser to support older versions of the grammar. In particular if `feature_version` is 5 or 6, the hacks for the `async` and `await` keyword from PEP 492 are reinstated. (For 7 or higher, these are unconditionally treated as keywords, but they are still special tokens rather than `NAME` tokens that the parser driver recognizes.) https://bugs.python.org/issue35975
474 lines
13 KiB
C
474 lines
13 KiB
C
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/* Parser-tokenizer link implementation */
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#include "pgenheaders.h"
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#include "tokenizer.h"
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#include "node.h"
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#include "grammar.h"
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#include "parser.h"
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#include "parsetok.h"
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#include "errcode.h"
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#include "graminit.h"
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/* Forward */
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static node *parsetok(struct tok_state *, grammar *, int, perrdetail *, int *);
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static int initerr(perrdetail *err_ret, PyObject * filename);
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typedef struct {
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int *items;
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size_t size;
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size_t num_items;
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} growable_int_array;
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static int
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growable_int_array_init(growable_int_array *arr, size_t initial_size) {
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assert(initial_size > 0);
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arr->items = malloc(initial_size * sizeof(*arr->items));
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arr->size = initial_size;
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arr->num_items = 0;
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return arr->items != NULL;
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}
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static int
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growable_int_array_add(growable_int_array *arr, int item) {
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if (arr->num_items >= arr->size) {
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arr->size *= 2;
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arr->items = realloc(arr->items, arr->size * sizeof(*arr->items));
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if (!arr->items) {
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return 0;
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}
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}
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arr->items[arr->num_items] = item;
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arr->num_items++;
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return 1;
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}
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static void
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growable_int_array_deallocate(growable_int_array *arr) {
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free(arr->items);
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}
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/* Parse input coming from a string. Return error code, print some errors. */
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node *
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PyParser_ParseString(const char *s, grammar *g, int start, perrdetail *err_ret)
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{
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return PyParser_ParseStringFlagsFilename(s, NULL, g, start, err_ret, 0);
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}
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node *
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PyParser_ParseStringFlags(const char *s, grammar *g, int start,
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perrdetail *err_ret, int flags)
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{
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return PyParser_ParseStringFlagsFilename(s, NULL,
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g, start, err_ret, flags);
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}
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node *
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PyParser_ParseStringFlagsFilename(const char *s, const char *filename,
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grammar *g, int start,
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perrdetail *err_ret, int flags)
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{
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int iflags = flags;
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return PyParser_ParseStringFlagsFilenameEx(s, filename, g, start,
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err_ret, &iflags);
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}
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node *
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PyParser_ParseStringObject(const char *s, PyObject *filename,
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grammar *g, int start,
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perrdetail *err_ret, int *flags)
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{
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struct tok_state *tok;
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int exec_input = start == file_input;
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if (initerr(err_ret, filename) < 0)
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return NULL;
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if (*flags & PyPARSE_IGNORE_COOKIE)
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tok = PyTokenizer_FromUTF8(s, exec_input);
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else
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tok = PyTokenizer_FromString(s, exec_input);
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if (tok == NULL) {
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err_ret->error = PyErr_Occurred() ? E_DECODE : E_NOMEM;
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return NULL;
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}
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if (*flags & PyPARSE_TYPE_COMMENTS) {
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tok->type_comments = 1;
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}
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Py_INCREF(err_ret->filename);
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tok->filename = err_ret->filename;
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if (*flags & PyPARSE_ASYNC_HACKS)
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tok->async_hacks = 1;
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return parsetok(tok, g, start, err_ret, flags);
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}
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node *
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PyParser_ParseStringFlagsFilenameEx(const char *s, const char *filename_str,
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grammar *g, int start,
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perrdetail *err_ret, int *flags)
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{
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node *n;
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PyObject *filename = NULL;
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if (filename_str != NULL) {
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filename = PyUnicode_DecodeFSDefault(filename_str);
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if (filename == NULL) {
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err_ret->error = E_ERROR;
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return NULL;
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}
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}
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n = PyParser_ParseStringObject(s, filename, g, start, err_ret, flags);
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Py_XDECREF(filename);
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return n;
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}
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/* Parse input coming from a file. Return error code, print some errors. */
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node *
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PyParser_ParseFile(FILE *fp, const char *filename, grammar *g, int start,
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const char *ps1, const char *ps2,
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perrdetail *err_ret)
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{
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return PyParser_ParseFileFlags(fp, filename, NULL,
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g, start, ps1, ps2, err_ret, 0);
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}
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node *
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PyParser_ParseFileFlags(FILE *fp, const char *filename, const char *enc,
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grammar *g, int start,
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const char *ps1, const char *ps2,
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perrdetail *err_ret, int flags)
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{
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int iflags = flags;
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return PyParser_ParseFileFlagsEx(fp, filename, enc, g, start, ps1,
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ps2, err_ret, &iflags);
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}
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node *
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PyParser_ParseFileObject(FILE *fp, PyObject *filename,
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const char *enc, grammar *g, int start,
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const char *ps1, const char *ps2,
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perrdetail *err_ret, int *flags)
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{
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struct tok_state *tok;
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if (initerr(err_ret, filename) < 0)
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return NULL;
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if ((tok = PyTokenizer_FromFile(fp, enc, ps1, ps2)) == NULL) {
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err_ret->error = E_NOMEM;
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return NULL;
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}
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if (*flags & PyPARSE_TYPE_COMMENTS) {
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tok->type_comments = 1;
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}
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Py_INCREF(err_ret->filename);
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tok->filename = err_ret->filename;
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return parsetok(tok, g, start, err_ret, flags);
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}
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node *
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PyParser_ParseFileFlagsEx(FILE *fp, const char *filename,
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const char *enc, grammar *g, int start,
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const char *ps1, const char *ps2,
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perrdetail *err_ret, int *flags)
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{
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node *n;
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PyObject *fileobj = NULL;
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if (filename != NULL) {
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fileobj = PyUnicode_DecodeFSDefault(filename);
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if (fileobj == NULL) {
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err_ret->error = E_ERROR;
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return NULL;
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}
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}
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n = PyParser_ParseFileObject(fp, fileobj, enc, g,
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start, ps1, ps2, err_ret, flags);
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Py_XDECREF(fileobj);
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return n;
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}
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#ifdef PY_PARSER_REQUIRES_FUTURE_KEYWORD
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#if 0
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static const char with_msg[] =
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"%s:%d: Warning: 'with' will become a reserved keyword in Python 2.6\n";
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static const char as_msg[] =
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"%s:%d: Warning: 'as' will become a reserved keyword in Python 2.6\n";
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static void
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warn(const char *msg, const char *filename, int lineno)
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{
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if (filename == NULL)
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filename = "<string>";
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PySys_WriteStderr(msg, filename, lineno);
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}
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#endif
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#endif
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/* Parse input coming from the given tokenizer structure.
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Return error code. */
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static node *
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parsetok(struct tok_state *tok, grammar *g, int start, perrdetail *err_ret,
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int *flags)
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{
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parser_state *ps;
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node *n;
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int started = 0;
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int col_offset, end_col_offset;
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growable_int_array type_ignores;
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if (!growable_int_array_init(&type_ignores, 10)) {
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err_ret->error = E_NOMEM;
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PyTokenizer_Free(tok);
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return NULL;
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}
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if ((ps = PyParser_New(g, start)) == NULL) {
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err_ret->error = E_NOMEM;
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PyTokenizer_Free(tok);
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return NULL;
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}
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#ifdef PY_PARSER_REQUIRES_FUTURE_KEYWORD
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if (*flags & PyPARSE_BARRY_AS_BDFL)
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ps->p_flags |= CO_FUTURE_BARRY_AS_BDFL;
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if (*flags & PyPARSE_TYPE_COMMENTS)
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ps->p_flags |= PyCF_TYPE_COMMENTS;
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#endif
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for (;;) {
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char *a, *b;
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int type;
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size_t len;
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char *str;
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col_offset = -1;
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int lineno;
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const char *line_start;
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type = PyTokenizer_Get(tok, &a, &b);
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if (type == ERRORTOKEN) {
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err_ret->error = tok->done;
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break;
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}
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if (type == ENDMARKER && started) {
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type = NEWLINE; /* Add an extra newline */
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started = 0;
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/* Add the right number of dedent tokens,
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except if a certain flag is given --
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codeop.py uses this. */
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if (tok->indent &&
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!(*flags & PyPARSE_DONT_IMPLY_DEDENT))
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{
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tok->pendin = -tok->indent;
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tok->indent = 0;
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}
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}
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else
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started = 1;
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len = (a != NULL && b != NULL) ? b - a : 0;
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str = (char *) PyObject_MALLOC(len + 1);
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if (str == NULL) {
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err_ret->error = E_NOMEM;
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break;
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}
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if (len > 0)
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strncpy(str, a, len);
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str[len] = '\0';
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#ifdef PY_PARSER_REQUIRES_FUTURE_KEYWORD
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if (type == NOTEQUAL) {
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if (!(ps->p_flags & CO_FUTURE_BARRY_AS_BDFL) &&
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strcmp(str, "!=")) {
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PyObject_FREE(str);
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err_ret->error = E_SYNTAX;
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break;
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}
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else if ((ps->p_flags & CO_FUTURE_BARRY_AS_BDFL) &&
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strcmp(str, "<>")) {
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PyObject_FREE(str);
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err_ret->expected = NOTEQUAL;
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err_ret->error = E_SYNTAX;
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break;
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}
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}
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#endif
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/* Nodes of type STRING, especially multi line strings
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must be handled differently in order to get both
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the starting line number and the column offset right.
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(cf. issue 16806) */
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lineno = type == STRING ? tok->first_lineno : tok->lineno;
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line_start = type == STRING ? tok->multi_line_start : tok->line_start;
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if (a != NULL && a >= line_start) {
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col_offset = Py_SAFE_DOWNCAST(a - line_start,
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intptr_t, int);
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}
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else {
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col_offset = -1;
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}
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if (b != NULL && b >= tok->line_start) {
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end_col_offset = Py_SAFE_DOWNCAST(b - tok->line_start,
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intptr_t, int);
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}
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else {
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end_col_offset = -1;
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}
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if (type == TYPE_IGNORE) {
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PyObject_FREE(str);
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if (!growable_int_array_add(&type_ignores, tok->lineno)) {
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err_ret->error = E_NOMEM;
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break;
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}
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continue;
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}
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if ((err_ret->error =
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PyParser_AddToken(ps, (int)type, str,
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lineno, col_offset, tok->lineno, end_col_offset,
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&(err_ret->expected))) != E_OK) {
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if (err_ret->error != E_DONE) {
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PyObject_FREE(str);
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err_ret->token = type;
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}
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break;
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}
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}
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if (err_ret->error == E_DONE) {
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n = ps->p_tree;
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ps->p_tree = NULL;
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if (n->n_type == file_input) {
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/* Put type_ignore nodes in the ENDMARKER of file_input. */
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int num;
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node *ch;
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size_t i;
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num = NCH(n);
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ch = CHILD(n, num - 1);
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REQ(ch, ENDMARKER);
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for (i = 0; i < type_ignores.num_items; i++) {
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PyNode_AddChild(ch, TYPE_IGNORE, NULL,
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type_ignores.items[i], 0,
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type_ignores.items[i], 0);
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}
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}
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/* Check that the source for a single input statement really
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is a single statement by looking at what is left in the
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buffer after parsing. Trailing whitespace and comments
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are OK. */
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if (start == single_input) {
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char *cur = tok->cur;
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char c = *tok->cur;
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for (;;) {
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while (c == ' ' || c == '\t' || c == '\n' || c == '\014')
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c = *++cur;
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if (!c)
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break;
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if (c != '#') {
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err_ret->error = E_BADSINGLE;
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PyNode_Free(n);
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n = NULL;
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break;
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}
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/* Suck up comment. */
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while (c && c != '\n')
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c = *++cur;
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}
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}
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}
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else
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n = NULL;
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growable_int_array_deallocate(&type_ignores);
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#ifdef PY_PARSER_REQUIRES_FUTURE_KEYWORD
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*flags = ps->p_flags;
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#endif
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PyParser_Delete(ps);
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if (n == NULL) {
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if (tok->done == E_EOF)
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err_ret->error = E_EOF;
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err_ret->lineno = tok->lineno;
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if (tok->buf != NULL) {
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size_t len;
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assert(tok->cur - tok->buf < INT_MAX);
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/* if we've managed to parse a token, point the offset to its start,
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* else use the current reading position of the tokenizer
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*/
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err_ret->offset = col_offset != -1 ? col_offset + 1 : ((int)(tok->cur - tok->buf));
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len = tok->inp - tok->buf;
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err_ret->text = (char *) PyObject_MALLOC(len + 1);
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if (err_ret->text != NULL) {
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if (len > 0)
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strncpy(err_ret->text, tok->buf, len);
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err_ret->text[len] = '\0';
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}
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}
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} else if (tok->encoding != NULL) {
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/* 'nodes->n_str' uses PyObject_*, while 'tok->encoding' was
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* allocated using PyMem_
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*/
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node* r = PyNode_New(encoding_decl);
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if (r)
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r->n_str = PyObject_MALLOC(strlen(tok->encoding)+1);
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if (!r || !r->n_str) {
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err_ret->error = E_NOMEM;
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if (r)
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PyObject_FREE(r);
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n = NULL;
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goto done;
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}
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strcpy(r->n_str, tok->encoding);
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PyMem_FREE(tok->encoding);
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tok->encoding = NULL;
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r->n_nchildren = 1;
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r->n_child = n;
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n = r;
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}
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done:
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PyTokenizer_Free(tok);
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if (n != NULL) {
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_PyNode_FinalizeEndPos(n);
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}
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return n;
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}
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static int
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initerr(perrdetail *err_ret, PyObject *filename)
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{
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err_ret->error = E_OK;
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err_ret->lineno = 0;
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err_ret->offset = 0;
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err_ret->text = NULL;
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err_ret->token = -1;
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err_ret->expected = -1;
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if (filename) {
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Py_INCREF(filename);
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err_ret->filename = filename;
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}
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else {
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err_ret->filename = PyUnicode_FromString("<string>");
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if (err_ret->filename == NULL) {
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err_ret->error = E_ERROR;
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return -1;
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}
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}
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return 0;
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}
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