Improved __future__ parser; still more to do
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
diff --git a/Include/compile.h b/Include/compile.h
index 5d65c5d..ecc1575 100644
--- a/Include/compile.h
+++ b/Include/compile.h
@@ -7,9 +7,6 @@
extern "C" {
#endif
-#define NESTED_SCOPES_DEFAULT 0
-#define FUTURE_NESTED_SCOPES "nested_scopes"
-
/* Bytecode object */
typedef struct {
PyObject_HEAD
@@ -51,6 +48,19 @@
/* same as struct above */
DL_IMPORT(int) PyCode_Addr2Line(PyCodeObject *, int);
+/* Future feature support */
+
+typedef struct {
+ int ff_last_lineno;
+ int ff_n_simple_stmt;
+ int ff_nested_scopes;
+} PyFutureFeatures;
+
+DL_IMPORT(PyFutureFeatures *) PyNode_Future(struct _node *, char *);
+
+#define NESTED_SCOPES_DEFAULT 0
+#define FUTURE_NESTED_SCOPES "nested_scopes"
+
/* for internal use only */
#define _PyCode_GETCODEPTR(co, pp) \
((*(co)->co_code->ob_type->tp_as_buffer->bf_getreadbuffer) \
diff --git a/Include/symtable.h b/Include/symtable.h
index eb0be1a..7d1e0c3 100644
--- a/Include/symtable.h
+++ b/Include/symtable.h
@@ -30,6 +30,7 @@
int st_errors; /* number of errors */
char *st_private; /* name of current class or NULL */
int st_tmpname; /* temporary name counter */
+ PyFutureFeatures *st_future; /* module's future features */
};
typedef struct _symtable_entry {
diff --git a/Makefile.pre.in b/Makefile.pre.in
index 43a7f79..94aa576 100644
--- a/Makefile.pre.in
+++ b/Makefile.pre.in
@@ -200,6 +200,7 @@
Python/errors.o \
Python/frozen.o \
Python/frozenmain.o \
+ Python/future.o \
Python/getargs.o \
Python/getcompiler.o \
Python/getcopyright.o \
diff --git a/Python/compile.c b/Python/compile.c
index 5de2362..0830855 100644
--- a/Python/compile.c
+++ b/Python/compile.c
@@ -55,9 +55,6 @@
#define ILLEGAL_DYNAMIC_SCOPE \
"%.100s: exec or 'import *' makes names ambiguous in nested scope"
-#define UNDEFINED_FUTURE_FEATURE \
-"future feature %.100s is not defined"
-
#define GLOBAL_AFTER_ASSIGN \
"name '%.400s' is assigned to before global declaration"
@@ -368,6 +365,7 @@
int c_nested; /* Is block nested funcdef or lamdef? */
int c_closure; /* Is nested w/freevars? */
struct symtable *c_symtable; /* pointer to module symbol table */
+ PyFutureFeatures *c_future; /* pointer to module's __future__ */
};
int is_free(int v)
@@ -3864,7 +3862,8 @@
sc.c_nested = 1;
} else {
sc.c_private = NULL;
- if (symtable_build(&sc, n) < 0) {
+ sc.c_future = PyNode_Future(n, filename);
+ if (sc.c_future == NULL || symtable_build(&sc, n) < 0) {
com_free(&sc);
return NULL;
}
@@ -3996,6 +3995,8 @@
{
if ((c->c_symtable = symtable_init()) == NULL)
return -1;
+ if (c->c_future->ff_nested_scopes)
+ c->c_symtable->st_nested_scopes = 1;
c->c_symtable->st_filename = c->c_filename;
symtable_enter_scope(c->c_symtable, TOP, TYPE(n), n->n_lineno);
if (c->c_symtable->st_errors > 0)
@@ -4280,44 +4281,6 @@
PyMem_Free((void *)st);
}
-/* XXX this code is a placeholder for correct code.
- from __future__ import name set language options */
-
-static int
-symtable_check_future(struct symtable *st, node *n)
-{
- int i;
- node *name = CHILD(n, 1);
-
- if (strcmp(STR(CHILD(name, 0)), "__future__") != 0)
- return 0;
- /* It is only legal to define __future__ features at the top
- of a module. If the current scope is not the module level
- or if there are any symbols defined, it is too late. */
- if (st->st_cur->ste_symbols != st->st_global
- || PyDict_Size(st->st_cur->ste_symbols) != 0) {
- PyErr_SetString(PyExc_SyntaxError,
- "imports from __future__ are only legal at the beginning of a module");
- return -1;
- }
- for (i = 3; i < NCH(n); ++i) {
- char *feature = STR(CHILD(CHILD(n, i), 0));
- /* Do a linear search through the defined features,
- assuming there aren't very many of them. */
- if (strcmp(feature, FUTURE_NESTED_SCOPES) == 0) {
- st->st_nested_scopes = 1;
- } else {
- PyErr_Format(PyExc_SyntaxError,
- UNDEFINED_FUTURE_FEATURE, feature);
- set_error_location(st->st_filename,
- st->st_cur->ste_lineno);
- st->st_errors++;
- return -1;
- }
- }
- return 1;
-}
-
/* When the compiler exits a scope, it must should update the scope's
free variable information with the list of free variables in its
children.
@@ -4910,7 +4873,6 @@
import_as_name: NAME [NAME NAME]
*/
if (STR(CHILD(n, 0))[0] == 'f') { /* from */
- symtable_check_future(st, n);
if (TYPE(CHILD(n, 3)) == STAR) {
st->st_cur->ste_optimized |= OPT_IMPORT_STAR;
} else {
diff --git a/Python/future.c b/Python/future.c
new file mode 100644
index 0000000..f67abc9
--- /dev/null
+++ b/Python/future.c
@@ -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;
+}
+
diff --git a/Python/symtable.c b/Python/symtable.c
index 3ec129d..aed8908 100644
--- a/Python/symtable.c
+++ b/Python/symtable.c
@@ -1,4 +1,5 @@
#include "Python.h"
+#include "compile.h"
#include "symtable.h"
#include "graminit.h"
#include "structmember.h"