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pythongh-97933: inline sync list/dict/set comprehensions
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17 files changed

Lines changed: 391 additions & 77 deletions

‎Doc/library/dis.rst‎

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@@ -1214,6 +1214,16 @@ iterations of the loop.
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.. versionadded:: 3.12
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.. opcode:: LOAD_FAST_OR_NULL (var_num)
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Pushes a reference to the local ``co_varnames[var_num]`` onto the stack, or
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pushes ``NULL`` onto the stack if the local variable has not been
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initialized. This opcode has the same runtime effect as ``LOAD_FAST``; it
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exists to maintain the invariant that ``LOAD_FAST`` will never load ``NULL``
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and may appear only where the variable is guaranteed to be initialized.
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.. versionadded:: 3.12
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.. opcode:: STORE_FAST (var_num)
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Stores ``STACK.pop()`` into the local ``co_varnames[var_num]``.

‎Include/internal/pycore_opcode.h‎

Lines changed: 4 additions & 4 deletions
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‎Include/internal/pycore_symtable.h‎

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@@ -64,6 +64,7 @@ typedef struct _symtable_entry {
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unsigned ste_needs_class_closure : 1; /* for class scopes, true if a
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closure over __class__
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should be created */
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unsigned ste_comp_inlined : 1; /* true if this comprehension is inlined */
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unsigned ste_comp_iter_target : 1; /* true if visiting comprehension target */
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int ste_comp_iter_expr; /* non-zero if visiting a comprehension range expression */
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int ste_lineno; /* first line of block */

‎Include/opcode.h‎

Lines changed: 7 additions & 6 deletions
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‎Lib/importlib/_bootstrap_external.py‎

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@@ -431,6 +431,7 @@ def _write_atomic(path, data, mode=0o666):
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# Python 3.12a5 3515 (Embed jump mask in COMPARE_OP oparg)
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# Python 3.12a5 3516 (Add COMPARE_AND_BRANCH instruction)
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# Python 3.12a5 3517 (Change YIELD_VALUE oparg to exception block depth)
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# Python 3.12a5 3518 (Inline sync list/dict/set comprehensions in the calling function)
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# Python 3.13 will start with 3550
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@@ -443,7 +444,7 @@ def _write_atomic(path, data, mode=0o666):
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# Whenever MAGIC_NUMBER is changed, the ranges in the magic_values array
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# in PC/launcher.c must also be updated.
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MAGIC_NUMBER = (3517).to_bytes(2, 'little') + b'\r\n'
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MAGIC_NUMBER = (3518).to_bytes(2, 'little') + b'\r\n'
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_RAW_MAGIC_NUMBER = int.from_bytes(MAGIC_NUMBER, 'little') # For import.c
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‎Lib/opcode.py‎

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@@ -196,6 +196,8 @@ def pseudo_op(name, op, real_ops):
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hascompare.append(141)
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def_op('CALL_FUNCTION_EX', 142) # Flags
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def_op('LOAD_FAST_OR_NULL', 143) # Local variable number, may load NULL if undefined
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haslocal.append(143)
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def_op('EXTENDED_ARG', 144)
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EXTENDED_ARG = 144

‎Lib/test/test_dis.py‎

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@@ -161,15 +161,15 @@ def bug708901():
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def bug1333982(x=[]):
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assert 0, ([s for s in x] +
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assert 0, ((s for s in x) +
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1)
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pass
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dis_bug1333982 = """\
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%3d RESUME 0
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%3d LOAD_ASSERTION_ERROR
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LOAD_CONST 1 (<code object <listcomp> at 0x..., file "%s", line %d>)
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LOAD_CONST 1 (<code object <genexpr> at 0x..., file "%s", line %d>)
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MAKE_FUNCTION 0
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LOAD_FAST 0 (x)
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GET_ITER
@@ -642,7 +642,7 @@ async def _co(x):
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def _h(y):
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def foo(x):
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'''funcdoc'''
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return [x + z for z in y]
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return list(x + z for z in y)
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return foo
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dis_nested_0 = """\
@@ -672,13 +672,15 @@ def foo(x):
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%3d RESUME 0
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%3d LOAD_CLOSURE 0 (x)
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%3d LOAD_GLOBAL 1 (NULL + list)
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LOAD_CLOSURE 0 (x)
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BUILD_TUPLE 1
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LOAD_CONST 1 (<code object <listcomp> at 0x..., file "%s", line %d>)
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LOAD_CONST 1 (<code object <genexpr> at 0x..., file "%s", line %d>)
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MAKE_FUNCTION 8 (closure)
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LOAD_DEREF 1 (y)
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GET_ITER
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CALL 0
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CALL 1
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RETURN_VALUE
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""" % (dis_nested_0,
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__file__,
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)
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dis_nested_2 = """%s
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Disassembly of <code object <listcomp> at 0x..., file "%s", line %d>:
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Disassembly of <code object <genexpr> at 0x..., file "%s", line %d>:
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COPY_FREE_VARS 1
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%3d RESUME 0
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BUILD_LIST 0
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%3d RETURN_GENERATOR
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POP_TOP
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RESUME 0
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LOAD_FAST 0 (.0)
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>> FOR_ITER 7 (to 26)
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>> FOR_ITER 9 (to 32)
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STORE_FAST 1 (z)
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LOAD_DEREF 2 (x)
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LOAD_FAST 1 (z)
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BINARY_OP 0 (+)
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LIST_APPEND 2
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JUMP_BACKWARD 9 (to 8)
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YIELD_VALUE 1
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RESUME 1
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POP_TOP
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JUMP_BACKWARD 11 (to 10)
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>> END_FOR
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LOAD_CONST 0 (None)
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RETURN_VALUE
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>> CALL_INTRINSIC_1 3
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RERAISE 1
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ExceptionTable:
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1 row
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""" % (dis_nested_1,
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__file__,
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_h.__code__.co_firstlineno + 3,

‎Lib/test/test_inspect.py‎

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@@ -4106,14 +4106,14 @@ def test(*args, **kwargs):
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@cpython_only
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def test_signature_bind_implicit_arg(self):
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# Issue #19611: getcallargs should work with set comprehensions
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# Issue #19611: getcallargs should work with comprehensions
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def make_set():
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return {z * z for z in range(5)}
4112-
setcomp_code = make_set.__code__.co_consts[1]
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setcomp_func = types.FunctionType(setcomp_code, {})
4111+
return set(z * z for z in range(5))
4112+
gencomp_code = make_set.__code__.co_consts[1]
4113+
gencomp_func = types.FunctionType(gencomp_code, {})
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41154115
iterator = iter(range(5))
4116-
self.assertEqual(self.call(setcomp_func, iterator), {0, 1, 4, 9, 16})
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self.assertEqual(set(self.call(gencomp_func, iterator)), {0, 1, 4, 9, 16})
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def test_signature_bind_posonly_kwargs(self):
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def foo(bar, /, **kwargs):

‎Lib/test/test_listcomps.py‎

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@@ -143,6 +143,48 @@
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>>> test_func()
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[2, 2, 2, 2, 2]
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A comprehension's iteration var, if in a cell, doesn't stomp on a previous value:
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>>> def test_func():
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... y = 10
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... items = [(lambda: y) for y in range(5)]
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... x = y
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... y = 20
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... return x, [z() for z in items]
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>>> test_func()
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(10, [4, 4, 4, 4, 4])
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A comprehension's iteration var doesn't shadow implicit globals for sibling scopes:
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>>> g = -1
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>>> def test_func():
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... def inner():
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... return g
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... [g for g in range(5)]
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... return inner
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>>> test_func()()
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-1
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A modification to a closed-over variable is visible in the outer scope:
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>>> def test_func():
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... x = -1
172+
... items = [(x:=y) for y in range(3)]
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... return x
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>>> test_func()
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2
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Comprehensions' scopes don't interact with each other:
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>>> def test_func():
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... lst = list(range(3))
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... ret = [lambda: x for x in lst]
182+
... inc = [x + 1 for x in lst]
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... [x for x in inc]
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... return ret
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>>> test_func()[0]()
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2
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"""
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‎Lib/test/test_trace.py‎

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@@ -187,9 +187,7 @@ def test_trace_list_comprehension(self):
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firstlineno_called = get_firstlineno(traced_doubler)
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expected = {
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(self.my_py_filename, firstlineno_calling + 1): 1,
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# List comprehensions work differently in 3.x, so the count
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# below changed compared to 2.x.
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(self.my_py_filename, firstlineno_calling + 2): 12,
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(self.my_py_filename, firstlineno_calling + 2): 11,
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(self.my_py_filename, firstlineno_calling + 3): 1,
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(self.my_py_filename, firstlineno_called + 1): 10,
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}

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