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/Objects/frameobject.c b/Objects/frameobject.c
index f541f1e..0f6372b 100644
--- a/Objects/frameobject.c
+++ b/Objects/frameobject.c
@@ -79,6 +79,7 @@
Py_XDECREF(f->f_builtins);
Py_XDECREF(f->f_globals);
Py_XDECREF(f->f_locals);
+ Py_XDECREF(f->f_closure);
Py_XDECREF(f->f_trace);
Py_XDECREF(f->f_exc_type);
Py_XDECREF(f->f_exc_value);
@@ -106,14 +107,14 @@
};
PyFrameObject *
-PyFrame_New(PyThreadState *tstate, PyCodeObject *code,
- PyObject *globals, PyObject *locals)
+PyFrame_New(PyThreadState *tstate, PyCodeObject *code, PyObject *globals,
+ PyObject *locals, PyObject *closure)
{
PyFrameObject *back = tstate->frame;
static PyObject *builtin_object;
PyFrameObject *f;
PyObject *builtins;
- int extras;
+ int extras, ncells;
if (builtin_object == NULL) {
builtin_object = PyString_InternFromString("__builtins__");
@@ -128,6 +129,7 @@
return NULL;
}
extras = code->co_stacksize + code->co_nlocals;
+ ncells = PyTuple_GET_SIZE(code->co_cellvars);
if (back == NULL || back->f_globals != globals) {
builtins = PyDict_GetItem(globals, builtin_object);
if (builtins != NULL && PyModule_Check(builtins))
@@ -197,6 +199,22 @@
locals = globals;
Py_INCREF(locals);
}
+ if (closure || ncells) {
+ int i, size;
+ size = ncells;
+ if (closure)
+ size += PyTuple_GET_SIZE(closure);
+ f->f_closure = PyTuple_New(size);
+ for (i = 0; i < ncells; ++i)
+ PyTuple_SET_ITEM(f->f_closure, i, PyCell_New(NULL));
+ for (i = ncells; i < size; ++i) {
+ PyObject *o = PyTuple_GET_ITEM(closure, i - ncells);
+ Py_INCREF(o);
+ PyTuple_SET_ITEM(f->f_closure, i, o);
+ }
+ }
+ else
+ f->f_closure = NULL;
f->f_locals = locals;
f->f_trace = NULL;
f->f_exc_type = f->f_exc_value = f->f_exc_traceback = NULL;