dummy entry to sys.modules, marking the absence of a submodule by the
same name.
Thus, if module foo.bar executes the statement "import time",
sys.modules['foo.time'] will be set to None, once the absence of a
module foo.time is confirmed (by looking for it in foo's path).
The next time when foo.bar (or any other submodule of foo) executes
"import time", no I/O is necessary to determine that there is no
module foo.time.
(Justification: It may seem strange to pollute sys.modules. However,
since we're doing the lookup anyway it's definitely the fastest
solution. This is the same convention that 'ni' uses and I haven't
heard any complaints.)
right thing.
Still to do:
- Make reload() of a submodule work.
- Performance tweaks -- currently, a submodule that tries to import a
global module *always* searches the package directory first, even if
the global module was already imported. Not sure how to solve this
one; probably need to record misses per package.
- Documentation!
This doesn't yet support "import a.b.c" or "from a.b.c import x", but
it does recognize directories. When importing a directory, it
initializes __path__ to a list containing the directory name, and
loads the __init__ module if found.
The (internal) find_module() and load_module() functions are
restructured so that they both also handle built-in and frozen modules
and Mac resources (and directories of course). The imp module's
find_module() and (new) load_module() also have this functionality.
Moreover, imp unconditionally defines constants for all module types,
and has two more new functions: find_module_in_package() and
find_module_in_directory().
There's also a new API function, PyImport_ImportModuleEx(), which
takes all four __import__ arguments (name, globals, locals, fromlist).
The last three may be NULL. This is currently the same as
PyImport_ImportModule() but in the future it will be able to do
relative dotted-path imports.
Other changes:
- bltinmodule.c: in __import__, call PyImport_ImportModuleEx().
- ceval.c: always pass the fromlist to __import__, even if it is a C
function, so PyImport_ImportModuleEx() is useful.
- getmtime.c: the function has a second argument, the FILE*, on which
it applies fstat(). According to Sjoerd this is much faster. The
first (pathname) argument is ignored, but remains for backward
compatibility (so the Mac version still works without changes).
By cleverly combining the new imp functionality, the full support for
dotted names in Python (mini.py, not checked in) is now about 7K,
lavishly commented (vs. 14K for ni plus 11K for ihooks, also lavishly
commented).
Good night!
- Changed semantics for initialized flag (again); forget the ref
counting, forget the fatal errors -- redundant calls to
Py_Initialize() or Py_Finalize() calls are simply ignored.
- Automatically import site.py on initialization, unless a flag is set
not to do this by main().
Added PyErr_MemoryErrorInst to hold the pre-instantiated instance when
using class based exceptions.
Simplified the creation of all built-in exceptions, both class based
and string based. Actually, for class based exceptions, the string
ones are still created just in case there's a problem creating the
class based ones (so you still get *some* exception handling!). Now
the init and fini functions run through a list of structure elements,
creating the strings (and optionally classes) for every entry.
initerrors(): the new base class exceptions StandardError,
LookupError, and NumberError are initialized when using string
exceptions, to tuples containing the list of derived string
exceptions. This GvR trick enables forward compatibility! One bit of
nastiness is that the C code has to know the inheritance tree embodied
in exceptions.py.
Added the two phase init and fini functions.
the -X command line option.
Py_Initialize(): Handle the two phase initialization of the built-in
module.
Py_Finalize(): Handle the two phase finalization of the built-in
module.
parse_syntax_error(): New function which parses syntax errors that
PyErr_Print() will catch. This correctly parses such errors
regardless of whether PyExc_SyntaxError is an old-style string
exception or new-fangled class exception.
PyErr_Print(): Many changes:
1. Normalize the exception.
2. Handle SystemExit exceptions which might be class based. Digs
the exit code out of the "code" attribute. String based
SystemExit is handled the same as before.
3. Handle SyntaxError exceptions which might be class based. Digs
the various information bits out of the instance's attributes
(see parse_syntax_error() for details). String based
SyntaxError still works too.
4. Don't write the `:' after the exception if the exception is
class based and has an empty string str() value.
(PyExc_MemoryErrorInst) raise this instead of PyExc_MemoryError. This
only happens when exception classes are enabled (e.g. when Python is
started with -X).
former rather than the latter, since PyErr_NormalizeException takes
PyObject** and I didn't want to change the interface for set_exc_info
(but I did want the changes propagated to eval_code2!).
UNPACK_LIST byte codes and added a third code path that allows
generalized sequence unpacking. Now both syntaxes:
a, b, c = seq
[a, b, c] = seq
can be used to unpack any sequence with the exact right number of
items.
unpack_sequence(): out-lined implementation of generalized sequence
unpacking. tuple and list unpacking are still inlined.
PyErr_GivenExceptionMatches().
set_exc_info(): make sure to normalize exceptions.
do_raise(): Use PyErr_NormalizeException() if type is a class.
loop_subscript(): Use PyErr_ExceptionMatches() instead of raw pointer
compare for PyExc_IndexError.
- int PyErr_GivenExceptionMatches(obj1, obj2)
Returns 1 if obj1 and obj2 are the same object, or if obj1 is an
instance of type obj2, or of a class derived from obj2
- int PyErr_ExceptionMatches(obj)
Higher level wrapper around PyErr_GivenExceptionMatches() which uses
PyErr_Occurred() as obj1. This will be the more commonly called
function.
- void PyErr_NormalizeException(typeptr, valptr, tbptr)
Normalizes exceptions, and places the normalized values in the
arguments. If type is not a class, this does nothing. If type is a
class, then it makes sure that value is an instance of the class by:
1. if instance is of the type, or a class derived from type, it does
nothing.
2. otherwise it instantiates the class, using the value as an
argument. If value is None, it uses an empty arg tuple, and if
the value is a tuple, it uses just that.
classes as their second arguments. The former takes a class as the
first argument and returns true iff first is second, or is a subclass
of second.
The latter takes any object as the first argument and returns true iff
first is an instance of the second, or any subclass of second.
Also, change all occurances of pointer compares against
PyExc_IndexError with PyErr_ExceptionMatches() calls.
ExitThread(). As discussed in c.l.p, this takes care of
initialization and finalization of thread-local storage allocated by
the C runtime system. Not sure whether non-MS compilers grok this
though (but who cares :-).
scheme based on object's types, have a simple two-phase scheme based
on object's *names*:
/* To make the execution order of destructors for global
objects a bit more predictable, we first zap all objects
whose name starts with a single underscore, before we clear
the entire dictionary. We zap them by replacing them with
None, rather than deleting them from the dictionary, to
avoid rehashing the dictionary (to some extent). */
Py_Initmodule(), which is a macro wrapper around it).
The return value is now a NULL pointer if the initialization failed.
This may make old modules fail with a SEGFAULT, since they don't
expect this kind of failure. That's OK, since (a) it "never" happens,
and (b) they would fail with a fatal error otherwise, anyway.
Tons of extension modules should now check the return value of
Py_Initmodule*() -- that's on my TODO list.
importdl.c: the MAXSUFFIXSIZE macro is now defined in importdl.h, and
the modules dictionary is now passed using PyImport_GetModuleDict().
Also undefine USE_SHLIB for AIX -- in AIX 4.2 and up, dlfcn.h exists
but we don't want to use it.
- Got rid of inspection of some environment variables.
- Got rid of Py_GetProgramName() and related logic.
- Print the version header *after* successful initialization.
for more!).
- The global flags that can be set from environment variables are now
set in Py_Initialize (except the silly Py_SuppressPrint, which no
longer exists). This saves duplicate code in frozenmain.c and main.c.
- Py_GetProgramName() is now here; added Py_SetProgramName(). An
embedding program should no longer provide Py_GetProgramName(),
instead it should call Py_SetProgramName() *before* calling
Py_Initialize().
PyThreadState pointer instead of a (frame) PyObject pointer. This
makes much more sense. It is backward incompatible, but that's no
problem, because (a) the heaviest users are the Py_{BEGIN,END}_
ALLOW_THREADS macros here, which have been fixed too; (b) there are
very few direct users; (c) those who use it are there will probably
appreciate the change.
Also, added new functions PyEval_AcquireThread() and
PyEval_ReleaseThread() which allows the threads created by the thread
module as well threads created by others (!) to set/reset the current
thread, and at the same time acquire/release the interpreter lock.
Much saner.
int+int, int-int, int <compareop> int, and list[int].
(Unfortunately, int*int is way too much code to inline.)
Also corrected a NULL that should have been a zero.
replaces its own entry in sys.module, reference count errors ensue;
even if there is no reference count problem, it would be preferable
for the import to yield the new thing in sys.modules anyway (if only
because that's what later imports will yield). This opens the road to
an official hack to implement a __getattr__ like feature for modules:
stick an instance in sys.modules[__name__].
have a unique name, otherwise they get squished by locals2fast (or
fast2locals, I dunno) when the debugger is invoked before they have
been transferred to real locals.
get/set/del item). This removes a pile of duplication. There's no
abstract operator for 'not' but I removed the function call for it
anyway -- it's a little faster in-line.
Guido van Rossum
Barry Warsaw