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Presumed correct compiler pass for future statements

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XXX still need to integrate into symtable API

compile.h: Remove ff_n_simple_stmt; obsolete.

           Add ff_found_docstring used internally to skip one and only
           one string at the beginning of a module.

compile.c: Add check for from __future__ imports to far into the file.

 	   In symtable_global() check for -1 returned from
	   symtable_lookup(), which signifies name not defined.

	   Add missing DECERF in symtable_add_def.

           Free c->c_future.

future.c:  Add special handling for multiple statements joined on a
	   single line using one or more semicolons; this form can
           include an illegal future statement that would otherwise be
           hard to detect.

	   Add support for detecting and skipping doc strings.
This commit is contained in:
Jeremy Hylton 2001-02-28 01:58:08 +00:00
parent 8e43cd7929
commit 39e2f3f824
3 changed files with 129 additions and 30 deletions
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123
Python/future.c
View file

@ -7,6 +7,8 @@
#define UNDEFINED_FUTURE_FEATURE "future feature %.100s is not defined"
#define FUTURE_POSSIBLE(FF) ((FF)->ff_last_lineno == -1)
static int
future_check_features(PyFutureFeatures *ff, node *n)
{
@ -28,6 +30,15 @@ future_check_features(PyFutureFeatures *ff, node *n)
return 0;
}
static void
future_error(node *n, char *filename)
{
PyErr_SetString(PyExc_SyntaxError,
"from __future__ imports must occur at the "
"beginning of the file");
/* XXX set filename and lineno */
}
/* Relevant portions of the grammar:
single_input: NEWLINE | simple_stmt | compound_stmt NEWLINE
@ -48,52 +59,82 @@ dotted_name: NAME ('.' NAME)*
*/
static int
future_parse(PyFutureFeatures *ff, node *n)
future_parse(PyFutureFeatures *ff, node *n, char *filename)
{
int i, r, found;
int i, r;
loop:
/* fprintf(stderr, "future_parse(%d, %d, %s)\n",
TYPE(n), NCH(n), (n == NULL) ? "NULL" : STR(n));
/* fprintf(stderr, "future_parse(%d, %d, %s, %d)\n",
TYPE(n), NCH(n), (n == NULL) ? "NULL" : STR(n),
n->n_lineno);
*/
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;
r = future_parse(ff, ch, filename);
if (!FUTURE_POSSIBLE(ff))
return r;
}
}
return 0;
case simple_stmt:
if (NCH(n) == 1) {
if (NCH(n) == 2) {
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++;
} else {
/* Deal with the special case of a series of
small statements on a single line. If a
future statement follows some other
statement, the SyntaxError is raised here.
In all other cases, the symtable pass
raises the exception.
*/
int found = 0, end_of_future = 0;
for (i = 0; i < NCH(n); i += 2) {
if (TYPE(CHILD(n, i)) == small_stmt) {
r = future_parse(ff, CHILD(n, i),
filename);
if (r < 1)
end_of_future = 1;
else {
found = 1;
if (end_of_future) {
future_error(n,
filename);
return -1;
}
}
}
}
if (found)
return 1;
else
return 0;
/* If we found one and only one, then the
current lineno is legal.
*/
if (found)
ff->ff_last_lineno = n->n_lineno + 1;
else
ff->ff_last_lineno = n->n_lineno;
if (end_of_future && found)
return 1;
else
return 0;
}
case stmt:
if (TYPE(CHILD(n, 0)) == simple_stmt) {
n = CHILD(n, 0);
goto loop;
} else if (TYPE(CHILD(n, 0)) == expr_stmt) {
n = CHILD(n, 0);
goto loop;
} else {
REQ(CHILD(n, 0), compound_stmt);
ff->ff_last_lineno = n->n_lineno;
@ -119,10 +160,42 @@ future_parse(PyFutureFeatures *ff, node *n)
return 1;
}
/* The cases below -- all of them! -- are necessary to find
and skip doc strings. */
case expr_stmt:
case testlist:
case test:
case and_test:
case not_test:
case comparison:
case expr:
case xor_expr:
case and_expr:
case shift_expr:
case arith_expr:
case term:
case factor:
case power:
if (NCH(n) == 1) {
n = CHILD(n, 0);
goto loop;
}
break;
case atom:
if (TYPE(CHILD(n, 0)) == STRING
&& ff->ff_found_docstring == 0) {
ff->ff_found_docstring = 1;
return 0;
}
ff->ff_last_lineno = n->n_lineno;
return 0;
default:
ff->ff_last_lineno = n->n_lineno;
return 0;
}
return 0;
}
PyFutureFeatures *
@ -133,11 +206,11 @@ PyNode_Future(node *n, char *filename)
ff = (PyFutureFeatures *)PyMem_Malloc(sizeof(PyFutureFeatures));
if (ff == NULL)
return NULL;
ff->ff_last_lineno = 0;
ff->ff_n_simple_stmt = -1;
ff->ff_found_docstring = 0;
ff->ff_last_lineno = -1;
ff->ff_nested_scopes = 0;
if (future_parse(ff, n) < 0) {
if (future_parse(ff, n, filename) < 0) {
PyMem_Free((void *)ff);
return NULL;
}