PEP 227 implementation
The majority of the changes are in the compiler. The mainloop changes
primarily to implement the new opcodes and to pass a function's
closure to eval_code2(). Frames and functions got new slots to hold
the closure.
Include/compile.h
Add co_freevars and co_cellvars slots to code objects.
Update PyCode_New() to take freevars and cellvars as arguments
Include/funcobject.h
Add func_closure slot to function objects.
Add GetClosure()/SetClosure() functions (and corresponding
macros) for getting at the closure.
Include/frameobject.h
PyFrame_New() now takes a closure.
Include/opcode.h
Add four new opcodes: MAKE_CLOSURE, LOAD_CLOSURE, LOAD_DEREF,
STORE_DEREF.
Remove comment about old requirement for opcodes to fit in 7
bits.
compile.c
Implement changes to code objects for co_freevars and co_cellvars.
Modify symbol table to use st_cur_name (string object for the name
of the current scope) and st_cur_children (list of nested blocks).
Also define st_nested, which might more properly be called
st_cur_nested. Add several DEF_XXX flags to track def-use
information for free variables.
New or modified functions of note:
com_make_closure(struct compiling *, PyCodeObject *)
Emit LOAD_CLOSURE opcodes as needed to pass cells for free
variables into nested scope.
com_addop_varname(struct compiling *, int, char *)
Emits opcodes for LOAD_DEREF and STORE_DEREF.
get_ref_type(struct compiling *, char *name)
Return NAME_CLOSURE if ref type is FREE or CELL
symtable_load_symbols(struct compiling *)
Decides what variables are cell or free based on def-use info.
Can now raise SyntaxError if nested scopes are mixed with
exec or from blah import *.
make_scope_info(PyObject *, PyObject *, int, int)
Helper functions for symtable scope stack.
symtable_update_free_vars(struct symtable *)
After a code block has been analyzed, it must check each of
its children for free variables that are not defined in the
block. If a variable is free in a child and not defined in
the parent, then it is defined by block the enclosing the
current one or it is a global. This does the right logic.
symtable_add_use() is now a macro for symtable_add_def()
symtable_assign(struct symtable *, node *)
Use goto instead of for (;;)
Fixed bug in symtable where name of keyword argument in function
call was treated as assignment in the scope of the call site. Ex:
def f():
g(a=2) # a was considered a local of f
ceval.c
eval_code2() now take one more argument, a closure.
Implement LOAD_CLOSURE, LOAD_DEREF, STORE_DEREF, MAKE_CLOSURE>
Also: When name error occurs for global variable, report that the
name was global in the error mesage.
Objects/frameobject.c
Initialize f_closure to be a tuple containing space for cellvars
and freevars. f_closure is NULL if neither are present.
Objects/funcobject.c
Add support for func_closure.
Python/import.c
Change the magic number.
Python/marshal.c
Track changes to code objects.
diff --git a/Python/ceval.c b/Python/ceval.c
index 199272c..c7b5696 100644
--- a/Python/ceval.c
+++ b/Python/ceval.c
@@ -33,13 +33,16 @@
typedef PyObject *(*callproc)(PyObject *, PyObject *, PyObject *);
+#define REPR(ob) PyString_AS_STRING(PyObject_Repr(ob))
+
/* Forward declarations */
static PyObject *eval_code2(PyCodeObject *,
PyObject *, PyObject *,
PyObject **, int,
PyObject **, int,
- PyObject **, int);
+ PyObject **, int,
+ PyObject *);
static PyObject *call_object(PyObject *, PyObject *, PyObject *);
static PyObject *call_cfunction(PyObject *, PyObject *, PyObject *);
@@ -78,6 +81,8 @@
#define NAME_ERROR_MSG \
"name '%.200s' is not defined"
+#define GLOBAL_NAME_ERROR_MSG \
+ "global name '%.200s' is not defined"
#define UNBOUNDLOCAL_ERROR_MSG \
"local variable '%.200s' referenced before assignment"
@@ -335,7 +340,8 @@
globals, locals,
(PyObject **)NULL, 0,
(PyObject **)NULL, 0,
- (PyObject **)NULL, 0);
+ (PyObject **)NULL, 0,
+ NULL);
}
@@ -344,7 +350,7 @@
static PyObject *
eval_code2(PyCodeObject *co, PyObject *globals, PyObject *locals,
PyObject **args, int argcount, PyObject **kws, int kwcount,
- PyObject **defs, int defcount)
+ PyObject **defs, int defcount, PyObject *closure)
{
#ifdef DXPAIRS
int lastopcode = 0;
@@ -425,11 +431,9 @@
lltrace = PyDict_GetItemString(globals, "__lltrace__") != NULL;
#endif
- f = PyFrame_New(
- tstate, /*back*/
+ f = PyFrame_New(tstate, /*back*/
co, /*code*/
- globals, /*globals*/
- locals); /*locals*/
+ globals, locals, closure);
if (f == NULL)
return NULL;
@@ -1535,7 +1539,7 @@
w = GETNAMEV(oparg);
if ((err = PyDict_DelItem(f->f_globals, w)) != 0)
format_exc_check_arg(
- PyExc_NameError, NAME_ERROR_MSG ,w);
+ PyExc_NameError, GLOBAL_NAME_ERROR_MSG, w);
break;
case LOAD_CONST:
@@ -1577,7 +1581,7 @@
if (x == NULL) {
format_exc_check_arg(
PyExc_NameError,
- NAME_ERROR_MSG ,w);
+ GLOBAL_NAME_ERROR_MSG ,w);
break;
}
}
@@ -1618,6 +1622,25 @@
SETLOCAL(oparg, NULL);
continue;
+ case LOAD_CLOSURE:
+ x = PyTuple_GET_ITEM(f->f_closure, oparg);
+ Py_INCREF(x);
+ PUSH(x);
+ break;
+
+ case LOAD_DEREF:
+ x = PyTuple_GET_ITEM(f->f_closure, oparg);
+ w = PyCell_Get(x);
+ Py_INCREF(w);
+ PUSH(w);
+ break;
+
+ case STORE_DEREF:
+ w = POP();
+ x = PyTuple_GET_ITEM(f->f_closure, oparg);
+ PyCell_Set(x, w);
+ continue;
+
case BUILD_TUPLE:
x = PyTuple_New(oparg);
if (x != NULL) {
@@ -1939,6 +1962,46 @@
PUSH(x);
break;
+ case MAKE_CLOSURE:
+ {
+ int nfree;
+ v = POP(); /* code object */
+ x = PyFunction_New(v, f->f_globals);
+ nfree = PyTuple_GET_SIZE(((PyCodeObject *)v)->co_freevars);
+ Py_DECREF(v);
+ /* XXX Maybe this should be a separate opcode? */
+ if (x != NULL && nfree > 0) {
+ v = PyTuple_New(nfree);
+ if (v == NULL) {
+ Py_DECREF(x);
+ x = NULL;
+ break;
+ }
+ while (--nfree >= 0) {
+ w = POP();
+ PyTuple_SET_ITEM(v, nfree, w);
+ }
+ err = PyFunction_SetClosure(x, v);
+ Py_DECREF(v);
+ }
+ if (x != NULL && oparg > 0) {
+ v = PyTuple_New(oparg);
+ if (v == NULL) {
+ Py_DECREF(x);
+ x = NULL;
+ break;
+ }
+ while (--oparg >= 0) {
+ w = POP();
+ PyTuple_SET_ITEM(v, oparg, w);
+ }
+ err = PyFunction_SetDefaults(x, v);
+ Py_DECREF(v);
+ }
+ PUSH(x);
+ break;
+ }
+
case BUILD_SLICE:
if (oparg == 3)
w = POP();
@@ -2761,8 +2824,8 @@
(PyCodeObject *)PyFunction_GET_CODE(func),
PyFunction_GET_GLOBALS(func), (PyObject *)NULL,
&PyTuple_GET_ITEM(arg, 0), PyTuple_Size(arg),
- k, nk,
- d, nd);
+ k, nk, d, nd,
+ PyFunction_GET_CLOSURE(func));
if (k != NULL)
PyMem_DEL(k);
@@ -2805,6 +2868,7 @@
PyObject *co = PyFunction_GET_CODE(func);
PyObject *globals = PyFunction_GET_GLOBALS(func);
PyObject *argdefs = PyFunction_GET_DEFAULTS(func);
+ PyObject *closure = PyFunction_GET_CLOSURE(func);
PyObject **d = NULL;
int nd = 0;
@@ -2814,7 +2878,8 @@
}
return eval_code2((PyCodeObject *)co, globals,
(PyObject *)NULL, (*pp_stack)-n, na,
- (*pp_stack)-2*nk, nk, d, nd);
+ (*pp_stack)-2*nk, nk, d, nd,
+ closure);
}
static PyObject *