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Improved __future__ parser; still more to do

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Makefile.pre.in: add target future.o

Include/compile.h: define PyFutureFeaters and PyNode_Future()
                   add c_future slot to struct compiling

Include/symtable.h: add st_future slot to struct symtable

Python/future.c: implementation of PyNode_Future()

Python/compile.c: use PyNode_Future() for nested_scopes support

Python/symtable.c: include compile.h to pick up PyFutureFeatures decl
This commit is contained in:
Jeremy Hylton 2001-02-27 19:07:02 +00:00
parent ed5e8234d7
commit 4db62b1e14
6 changed files with 167 additions and 46 deletions
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146
Python/future.c Normal file
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@ -0,0 +1,146 @@
#include "Python.h"
#include "node.h"
#include "token.h"
#include "graminit.h"
#include "compile.h"
#include "symtable.h"
#define UNDEFINED_FUTURE_FEATURE "future feature %.100s is not defined"
static int
future_check_features(PyFutureFeatures *ff, node *n)
{
int i;
char *feature;
REQ(n, import_stmt); /* must by from __future__ import ... */
for (i = 3; i < NCH(n); ++i) {
feature = STR(CHILD(CHILD(n, i), 0));
if (strcmp(feature, FUTURE_NESTED_SCOPES) == 0) {
ff->ff_nested_scopes = 1;
} else {
PyErr_Format(PyExc_SyntaxError,
UNDEFINED_FUTURE_FEATURE, feature);
return -1;
}
}
return 0;
}
/* Relevant portions of the grammar:
single_input: NEWLINE | simple_stmt | compound_stmt NEWLINE
file_input: (NEWLINE | stmt)* ENDMARKER
stmt: simple_stmt | compound_stmt
simple_stmt: small_stmt (';' small_stmt)* [';'] NEWLINE
small_stmt: expr_stmt | print_stmt | del_stmt | pass_stmt | flow_stmt | import_stmt | global_stmt | exec_stmt | assert_stmt
import_stmt: 'import' dotted_as_name (',' dotted_as_name)* | 'from' dotted_name 'import' ('*' | import_as_name (',' import_as_name)*)
import_as_name: NAME [NAME NAME]
dotted_as_name: dotted_name [NAME NAME]
dotted_name: NAME ('.' NAME)*
*/
/* future_parse() return values:
-1 indicates an error occurred, e.g. unknown feature name
0 indicates no feature was found
1 indicates a feature was found
*/
static int
future_parse(PyFutureFeatures *ff, node *n)
{
int i, r, found;
loop:
/* fprintf(stderr, "future_parse(%d, %d, %s)\n",
TYPE(n), NCH(n), (n == NULL) ? "NULL" : STR(n));
*/
switch (TYPE(n)) {
case file_input:
for (i = 0; i < NCH(n); i++) {
node *ch = CHILD(n, i);
if (TYPE(ch) == stmt) {
n = ch;
goto loop;
}
}
return 0;
case simple_stmt:
if (NCH(n) == 1) {
REQ(CHILD(n, 0), small_stmt);
n = CHILD(n, 0);
goto loop;
}
found = 0;
for (i = 0; i < NCH(n); ++i)
if (TYPE(CHILD(n, i)) == small_stmt) {
r = future_parse(ff, CHILD(n, i));
if (r < 1) {
ff->ff_last_lineno = n->n_lineno;
ff->ff_n_simple_stmt = i;
return r;
} else
found++;
}
if (found)
return 1;
else
return 0;
case stmt:
if (TYPE(CHILD(n, 0)) == simple_stmt) {
n = CHILD(n, 0);
goto loop;
} else {
REQ(CHILD(n, 0), compound_stmt);
ff->ff_last_lineno = n->n_lineno;
return 0;
}
case small_stmt:
n = CHILD(n, 0);
goto loop;
case import_stmt: {
node *name;
if (STR(CHILD(n, 0))[0] != 'f') { /* from */
ff->ff_last_lineno = n->n_lineno;
return 0;
}
name = CHILD(n, 1);
if (strcmp(STR(CHILD(name, 0)), "__future__") != 0)
return 0;
if (future_check_features(ff, n) < 0)
return -1;
return 1;
}
default:
ff->ff_last_lineno = n->n_lineno;
return 0;
}
}
PyFutureFeatures *
PyNode_Future(node *n, char *filename)
{
PyFutureFeatures *ff;
ff = (PyFutureFeatures *)PyMem_Malloc(sizeof(PyFutureFeatures));
if (ff == NULL)
return NULL;
ff->ff_last_lineno = 0;
ff->ff_n_simple_stmt = -1;
ff->ff_nested_scopes = 0;
if (future_parse(ff, n) < 0) {
PyMem_Free((void *)ff);
return NULL;
}
return ff;
}