mirror of https://github.com/python/cpython
147 lines
3.1 KiB
C
147 lines
3.1 KiB
C
#include "Python.h"
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#include "node.h"
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#include "token.h"
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#include "graminit.h"
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#include "compile.h"
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#include "symtable.h"
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#define UNDEFINED_FUTURE_FEATURE "future feature %.100s is not defined"
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static int
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future_check_features(PyFutureFeatures *ff, node *n)
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{
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int i;
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char *feature;
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REQ(n, import_stmt); /* must by from __future__ import ... */
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for (i = 3; i < NCH(n); ++i) {
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feature = STR(CHILD(CHILD(n, i), 0));
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if (strcmp(feature, FUTURE_NESTED_SCOPES) == 0) {
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ff->ff_nested_scopes = 1;
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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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return -1;
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}
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}
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return 0;
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}
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/* Relevant portions of the grammar:
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single_input: NEWLINE | simple_stmt | compound_stmt NEWLINE
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file_input: (NEWLINE | stmt)* ENDMARKER
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stmt: simple_stmt | compound_stmt
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simple_stmt: small_stmt (';' small_stmt)* [';'] NEWLINE
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small_stmt: expr_stmt | print_stmt | del_stmt | pass_stmt | flow_stmt | import_stmt | global_stmt | exec_stmt | assert_stmt
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import_stmt: 'import' dotted_as_name (',' dotted_as_name)* | 'from' dotted_name 'import' ('*' | import_as_name (',' import_as_name)*)
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import_as_name: NAME [NAME NAME]
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dotted_as_name: dotted_name [NAME NAME]
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dotted_name: NAME ('.' NAME)*
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*/
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/* future_parse() return values:
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-1 indicates an error occurred, e.g. unknown feature name
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0 indicates no feature was found
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1 indicates a feature was found
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*/
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static int
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future_parse(PyFutureFeatures *ff, node *n)
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{
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int i, r, found;
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loop:
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/* fprintf(stderr, "future_parse(%d, %d, %s)\n",
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TYPE(n), NCH(n), (n == NULL) ? "NULL" : STR(n));
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*/
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switch (TYPE(n)) {
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case file_input:
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for (i = 0; i < NCH(n); i++) {
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node *ch = CHILD(n, i);
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if (TYPE(ch) == stmt) {
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n = ch;
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goto loop;
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}
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}
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return 0;
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case simple_stmt:
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if (NCH(n) == 1) {
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REQ(CHILD(n, 0), small_stmt);
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n = CHILD(n, 0);
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goto loop;
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}
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found = 0;
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for (i = 0; i < NCH(n); ++i)
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if (TYPE(CHILD(n, i)) == small_stmt) {
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r = future_parse(ff, CHILD(n, i));
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if (r < 1) {
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ff->ff_last_lineno = n->n_lineno;
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ff->ff_n_simple_stmt = i;
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return r;
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} else
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found++;
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}
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if (found)
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return 1;
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else
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return 0;
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case stmt:
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if (TYPE(CHILD(n, 0)) == simple_stmt) {
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n = CHILD(n, 0);
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goto loop;
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} else {
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REQ(CHILD(n, 0), compound_stmt);
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ff->ff_last_lineno = n->n_lineno;
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return 0;
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}
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case small_stmt:
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n = CHILD(n, 0);
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goto loop;
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case import_stmt: {
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node *name;
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if (STR(CHILD(n, 0))[0] != 'f') { /* from */
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ff->ff_last_lineno = n->n_lineno;
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return 0;
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}
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name = CHILD(n, 1);
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if (strcmp(STR(CHILD(name, 0)), "__future__") != 0)
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return 0;
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if (future_check_features(ff, n) < 0)
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return -1;
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return 1;
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}
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default:
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ff->ff_last_lineno = n->n_lineno;
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return 0;
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}
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}
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PyFutureFeatures *
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PyNode_Future(node *n, char *filename)
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{
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PyFutureFeatures *ff;
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ff = (PyFutureFeatures *)PyMem_Malloc(sizeof(PyFutureFeatures));
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if (ff == NULL)
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return NULL;
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ff->ff_last_lineno = 0;
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ff->ff_n_simple_stmt = -1;
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ff->ff_nested_scopes = 0;
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if (future_parse(ff, n) < 0) {
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PyMem_Free((void *)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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