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gh-97933: (PEP 709) inline list/dict/set comprehensions (#101441)

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Co-authored-by: Irit Katriel <1055913+iritkatriel@users.noreply.github.com>
Co-authored-by: Erlend E. Aasland <erlend.aasland@protonmail.com>
This commit is contained in:
Carl Meyer 2023-05-09 11:02:14 -06:00 • committed by GitHub
parent 0aeda29793
commit c3b595e73e
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GPG key ID: 4AEE18F83AFDEB23
27 changed files with 1243 additions and 695 deletions
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136
Python/symtable.c
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@ -103,6 +103,7 @@ ste_new(struct symtable *st, identifier name, _Py_block_ty block,
ste->ste_comprehension = NoComprehension;
ste->ste_returns_value = 0;
ste->ste_needs_class_closure = 0;
ste->ste_comp_inlined = 0;
ste->ste_comp_iter_target = 0;
ste->ste_comp_iter_expr = 0;
@ -558,6 +559,67 @@ analyze_name(PySTEntryObject *ste, PyObject *scopes, PyObject *name, long flags,
return 1;
}
static int
is_free_in_any_child(PySTEntryObject *entry, PyObject *key)
{
for (Py_ssize_t i = 0; i < PyList_GET_SIZE(entry->ste_children); i++) {
PySTEntryObject *child_ste = (PySTEntryObject *)PyList_GET_ITEM(
entry->ste_children, i);
long scope = _PyST_GetScope(child_ste, key);
if (scope == FREE) {
return 1;
}
}
return 0;
}
static int
inline_comprehension(PySTEntryObject *ste, PySTEntryObject *comp,
PyObject *scopes, PyObject *comp_free)
{
PyObject *k, *v;
Py_ssize_t pos = 0;
while (PyDict_Next(comp->ste_symbols, &pos, &k, &v)) {
// skip comprehension parameter
long comp_flags = PyLong_AS_LONG(v);
if (comp_flags & DEF_PARAM) {
assert(_PyUnicode_EqualToASCIIString(k, ".0"));
continue;
}
int scope = (comp_flags >> SCOPE_OFFSET) & SCOPE_MASK;
int only_flags = comp_flags & ((1 << SCOPE_OFFSET) - 1);
PyObject *existing = PyDict_GetItemWithError(ste->ste_symbols, k);
if (existing == NULL && PyErr_Occurred()) {
return 0;
}
if (!existing) {
// name does not exist in scope, copy from comprehension
assert(scope != FREE || PySet_Contains(comp_free, k) == 1);
PyObject *v_flags = PyLong_FromLong(only_flags);
if (v_flags == NULL) {
return 0;
}
int ok = PyDict_SetItem(ste->ste_symbols, k, v_flags);
Py_DECREF(v_flags);
if (ok < 0) {
return 0;
}
SET_SCOPE(scopes, k, scope);
}
else {
// free vars in comprehension that are locals in outer scope can
// now simply be locals, unless they are free in comp children
if ((PyLong_AsLong(existing) & DEF_BOUND) &&
!is_free_in_any_child(comp, k)) {
if (PySet_Discard(comp_free, k) < 0) {
return 0;
}
}
}
}
return 1;
}
#undef SET_SCOPE
/* If a name is defined in free and also in locals, then this block
@ -727,17 +789,17 @@ error:
static int
analyze_child_block(PySTEntryObject *entry, PyObject *bound, PyObject *free,
PyObject *global, PyObject* child_free);
PyObject *global, PyObject **child_free);
static int
analyze_block(PySTEntryObject *ste, PyObject *bound, PyObject *free,
PyObject *global)
{
PyObject *name, *v, *local = NULL, *scopes = NULL, *newbound = NULL;
PyObject *newglobal = NULL, *newfree = NULL, *allfree = NULL;
PyObject *newglobal = NULL, *newfree = NULL;
PyObject *temp;
int i, success = 0;
Py_ssize_t pos = 0;
int success = 0;
Py_ssize_t i, pos = 0;
local = PySet_New(NULL); /* collect new names bound in block */
if (!local)
@ -746,8 +808,8 @@ analyze_block(PySTEntryObject *ste, PyObject *bound, PyObject *free,
if (!scopes)
goto error;
/* Allocate new global and bound variable dictionaries. These
dictionaries hold the names visible in nested blocks. For
/* Allocate new global, bound and free variable sets. These
sets hold the names visible in nested blocks. For
ClassBlocks, the bound and global names are initialized
before analyzing names, because class bindings aren't
visible in methods. For other blocks, they are initialized
@ -826,28 +888,55 @@ analyze_block(PySTEntryObject *ste, PyObject *bound, PyObject *free,
newbound, newglobal now contain the names visible in
nested blocks. The free variables in the children will
be collected in allfree.
be added to newfree.
*/
allfree = PySet_New(NULL);
if (!allfree)
goto error;
for (i = 0; i < PyList_GET_SIZE(ste->ste_children); ++i) {
PyObject *child_free = NULL;
PyObject *c = PyList_GET_ITEM(ste->ste_children, i);
PySTEntryObject* entry;
assert(c && PySTEntry_Check(c));
entry = (PySTEntryObject*)c;
// we inline all non-generator-expression comprehensions
int inline_comp =
entry->ste_comprehension &&
!entry->ste_generator;
if (!analyze_child_block(entry, newbound, newfree, newglobal,
allfree))
&child_free))
{
goto error;
}
if (inline_comp) {
if (!inline_comprehension(ste, entry, scopes, child_free)) {
Py_DECREF(child_free);
goto error;
}
entry->ste_comp_inlined = 1;
}
temp = PyNumber_InPlaceOr(newfree, child_free);
Py_DECREF(child_free);
if (!temp)
goto error;
Py_DECREF(temp);
/* Check if any children have free variables */
if (entry->ste_free || entry->ste_child_free)
ste->ste_child_free = 1;
}
temp = PyNumber_InPlaceOr(newfree, allfree);
if (!temp)
goto error;
Py_DECREF(temp);
/* Splice children of inlined comprehensions into our children list */
for (i = PyList_GET_SIZE(ste->ste_children) - 1; i >= 0; --i) {
PyObject* c = PyList_GET_ITEM(ste->ste_children, i);
PySTEntryObject* entry;
assert(c && PySTEntry_Check(c));
entry = (PySTEntryObject*)c;
if (entry->ste_comp_inlined &&
PyList_SetSlice(ste->ste_children, i, i + 1,
entry->ste_children) < 0)
{
goto error;
}
}
/* Check if any local variables must be converted to cell variables */
if (ste->ste_type == FunctionBlock && !analyze_cells(scopes, newfree))
@ -870,7 +959,6 @@ analyze_block(PySTEntryObject *ste, PyObject *bound, PyObject *free,
Py_XDECREF(newbound);
Py_XDECREF(newglobal);
Py_XDECREF(newfree);
Py_XDECREF(allfree);
if (!success)
assert(PyErr_Occurred());
return success;
@ -878,16 +966,15 @@ analyze_block(PySTEntryObject *ste, PyObject *bound, PyObject *free,
static int
analyze_child_block(PySTEntryObject *entry, PyObject *bound, PyObject *free,
PyObject *global, PyObject* child_free)
PyObject *global, PyObject** child_free)
{
PyObject *temp_bound = NULL, *temp_global = NULL, *temp_free = NULL;
PyObject *temp;
/* Copy the bound and global dictionaries.
/* Copy the bound/global/free sets.
These dictionaries are used by all blocks enclosed by the
These sets are used by all blocks enclosed by the
current block. The analyze_block() call modifies these
dictionaries.
sets.
*/
temp_bound = PySet_New(bound);
@ -902,12 +989,8 @@ analyze_child_block(PySTEntryObject *entry, PyObject *bound, PyObject *free,
if (!analyze_block(entry, temp_bound, temp_free, temp_global))
goto error;
temp = PyNumber_InPlaceOr(child_free, temp_free);
if (!temp)
goto error;
Py_DECREF(temp);
*child_free = temp_free;
Py_DECREF(temp_bound);
Py_DECREF(temp_free);
Py_DECREF(temp_global);
return 1;
error:
@ -2216,4 +2299,3 @@ _Py_Mangle(PyObject *privateobj, PyObject *ident)
assert(_PyUnicode_CheckConsistency(result, 1));
return result;
}