sees it (test_iter.py is unchanged).
- Added a tp_iternext slot, which calls the iterator's next() method;
this is much faster for built-in iterators over built-in types
such as lists and dicts, speeding up pybench's ForLoop with about
25% compared to Python 2.1. (Now there's a good argument for
iterators. ;-)
- Renamed the built-in sequence iterator SeqIter, affecting the C API
functions for it. (This frees up the PyIter prefix for generic
iterator operations.)
- Added PyIter_Check(obj), which checks that obj's type has a
tp_iternext slot and that the proper feature flag is set.
- Added PyIter_Next(obj) which calls the tp_iternext slot. It has a
somewhat complex return condition due to the need for speed: when it
returns NULL, it may not have set an exception condition, meaning
the iterator is exhausted; when the exception StopIteration is set
(or a derived exception class), it means the same thing; any other
exception means some other error occurred.
new slot tp_iter in type object, plus new flag Py_TPFLAGS_HAVE_ITER
new C API PyObject_GetIter(), calls tp_iter
new builtin iter(), with two forms: iter(obj), and iter(function, sentinel)
new internal object types iterobject and calliterobject
new exception StopIteration
new opcodes for "for" loops, GET_ITER and FOR_ITER (also supported by dis.py)
new magic number for .pyc files
new special method for instances: __iter__() returns an iterator
iteration over dictionaries: "for x in dict" iterates over the keys
iteration over files: "for x in file" iterates over lines
TODO:
documentation
test suite
decide whether to use a different way to spell iter(function, sentinal)
decide whether "for key in dict" is a good idea
use iterators in map/filter/reduce, min/max, and elsewhere (in/not in?)
speed tuning (make next() a slot tp_next???)
now raises NameError instead of UnboundLocalError, because the var in
question is definitely not local. (This affects test_scope.py)
Also update the recent fix by Ping using get_func_name(). Replace
tests of get_func_name() return value with call to get_func_desc() to
match all the other uses.
Calling an unbound method on a C extension class without providing
an instance can yield a segfault. Try "Exception.__init__()" or
"ValueError.__init__()".
This is a simple fix. The error-reporting bits in call_method
mistakenly treat the misleadingly-named variable "func" as a
function, when in fact it is a method.
If we let get_func_name take care of the work, all is fine.
Fix based on patch #414750 by Michael Hudson.
New functions get_func_name() and get_func_desc() return reasonable
names and descriptions for all objects. XXX Even objects that aren't
actually callable.
pickle.py
The code implicitly assumed that all ints fit in 4 bytes, causing all
sorts of mischief (from nonsense results to corrupted pickles).
Repaired that.
marshal.c
The int marshaling code assumed that right shifts of signed longs
sign-extend. Repaired that.
Jeffery Collins pointed out that filterstring decrefs a character object
before it's done using it. This works by accident today because another
module always happens to have an active reference too at the time. The
accident doesn't work after his Pippy modifications, and since it *is*
an accident even in the mainline Python, it should work by design there too.
The patch accomplishes that.
but apparently he had to go to school, so I am checking it in for him.
This makes PyRun_HandleSystemExit() a static instead, called
handle_system_exit(), and let it use the current exception rather than
passing in an exception. This slightly simplifies the code.
Update docstring and library reference section on 'sys' module.
New API PyErr_Display, just for displaying errors, called by excepthook.
Uncaught exceptions now call sys.excepthook; if that fails, we fall back
to calling PyErr_Display directly.
Also comes with sys.__excepthook__ and sys.__displayhook__.
If a module has a future statement enabling nested scopes, they are
also enable for the exec statement and the functions compile() and
execfile() if they occur in the module.
If Python is run with the -i option, which enters interactive mode
after executing a script, and the script it runs enables nested
scopes, they are also enabled in interactive mode.
XXX The use of -i with -c "from __future__ import nested_scopes" is
not supported. What's the point?
To support these changes, many function variants have been added to
pythonrun.c. All the variants names end with Flags and they take an
extra PyCompilerFlags * argument. It is possible that this complexity
will be eliminated in a future version of the interpreter in which
nested scopes are not optional.
frees. Note there doesn't seem to be any way to test LocalsToFast(),
because the instructions that trigger it are illegal in nested scopes
with free variables.
Fix allocation strategy for cells that are also formal parameters.
Instead of emitting LOAD_FAST / STORE_DEREF pairs for each parameter,
have the argument handling code in eval_code2() do the right thing.
A side-effect of this change is that cell variables that are also
arguments are listed at the front of co_cellvars in the order they
appear in the argument list.
has a binding for the name. The fix is in two places:
- in symtable_update_free_vars, ignore a global stmt in a class scope
- in symtable_load_symbols, add extra handling for names that are
defined at class scope and free in a method
Closes SF bug 407800
with free variables. Thanks to Martin v. Loewis for finding two of
the problems. This fixes SF buf 405583.
There is also a C API change: PyFrame_New() is reverting to its
pre-2.1 signature. The change introduced by nested scopes was a
mistake. XXX Is this okay between beta releases?
cell_clear(), the GC helper, must decref its reference to break
cycles.
frame_dealloc() must dealloc all cell vars and free vars in addition
to locals.
eval_code2() setup code must INCREF cells it copies out of the
closure.
The STORE_DEREF opcode implementation must DECREF the object it passes
to PyCell_Set().
Made sure that the warnings issued by symtable_check_unoptimized()
(about import * and exec) contain the proper filename and line number,
and are transformed into SyntaxError exceptions with -Werror.
(Also remove warning about module-level global decl, because we can't
distinguish from code passed to exec.)
Define PyCompilerFlags type contains a single element,
cf_nested_scopes, that is true if a nested scopes future statement has
been entered at the interactive prompt.
New API functions:
PyNode_CompileFlags()
PyRun_InteractiveOneFlags()
-- same as their non Flags counterparts except that the take an
optional PyCompilerFlags pointer
compile.c: In jcompile() use PyCompilerFlags argument. If
cf_nested_scopes is true, compile code with nested scopes. If it
is false, but the code has a valid future nested scopes statement,
set it to true.
pythonrun.c: Create a new PyCompilerFlags object in
PyRun_InteractiveLoop() and thread it through to
PyRun_InteractiveOneFlags().
the more recent versions of that platform, so we use the value (time_t)(-1)
as the error value. This is the type used in the OpenVMS documentation:
http://www.openvms.compaq.com/commercial/c/5763p048.htm#inde
This closes SF tracker bug #404240.
Also clean up an exception message when detecting overflow of time_t values
beyond 4 bytes.
from __future__ import nested_scopes
x=7
def f():
x=1
def g():
global x
def i():
def h():
return x
return h()
return i()
return g()
print f()
print x
This kind of code didn't work correctly because x was treated as free
in i, leading to an attempt to load x in g to make a closure for i.
Solution is to make global decl apply to nested scopes unless their is
an assignment. Thus, x in h is global.
Jeremy Hylton
Guido van Rossum
Tim Peters
Fred Drake
Ka-Ping Yee
Jack Jansen
Martin v. Löwis