Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 1 | |
| 2 | :mod:`inspect` --- Inspect live objects |
| 3 | ======================================= |
| 4 | |
| 5 | .. module:: inspect |
| 6 | :synopsis: Extract information and source code from live objects. |
| 7 | .. moduleauthor:: Ka-Ping Yee <ping@lfw.org> |
| 8 | .. sectionauthor:: Ka-Ping Yee <ping@lfw.org> |
| 9 | |
| 10 | |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 11 | The :mod:`inspect` module provides several useful functions to help get |
| 12 | information about live objects such as modules, classes, methods, functions, |
| 13 | tracebacks, frame objects, and code objects. For example, it can help you |
| 14 | examine the contents of a class, retrieve the source code of a method, extract |
| 15 | and format the argument list for a function, or get all the information you need |
| 16 | to display a detailed traceback. |
| 17 | |
| 18 | There are four main kinds of services provided by this module: type checking, |
| 19 | getting source code, inspecting classes and functions, and examining the |
| 20 | interpreter stack. |
| 21 | |
| 22 | |
| 23 | .. _inspect-types: |
| 24 | |
| 25 | Types and members |
| 26 | ----------------- |
| 27 | |
| 28 | The :func:`getmembers` function retrieves the members of an object such as a |
Christian Heimes | 7864476 | 2008-03-04 23:39:23 +0000 | [diff] [blame] | 29 | class or module. The sixteen functions whose names begin with "is" are mainly |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 30 | provided as convenient choices for the second argument to :func:`getmembers`. |
| 31 | They also help you determine when you can expect to find the following special |
| 32 | attributes: |
| 33 | |
Georg Brandl | 55ac8f0 | 2007-09-01 13:51:09 +0000 | [diff] [blame] | 34 | +-----------+-----------------+---------------------------+ |
| 35 | | Type | Attribute | Description | |
| 36 | +===========+=================+===========================+ |
| 37 | | module | __doc__ | documentation string | |
| 38 | +-----------+-----------------+---------------------------+ |
| 39 | | | __file__ | filename (missing for | |
| 40 | | | | built-in modules) | |
| 41 | +-----------+-----------------+---------------------------+ |
| 42 | | class | __doc__ | documentation string | |
| 43 | +-----------+-----------------+---------------------------+ |
| 44 | | | __module__ | name of module in which | |
| 45 | | | | this class was defined | |
| 46 | +-----------+-----------------+---------------------------+ |
| 47 | | method | __doc__ | documentation string | |
| 48 | +-----------+-----------------+---------------------------+ |
| 49 | | | __name__ | name with which this | |
| 50 | | | | method was defined | |
| 51 | +-----------+-----------------+---------------------------+ |
Christian Heimes | ff73795 | 2007-11-27 10:40:20 +0000 | [diff] [blame] | 52 | | | __func__ | function object | |
Georg Brandl | 55ac8f0 | 2007-09-01 13:51:09 +0000 | [diff] [blame] | 53 | | | | containing implementation | |
| 54 | | | | of method | |
| 55 | +-----------+-----------------+---------------------------+ |
Christian Heimes | ff73795 | 2007-11-27 10:40:20 +0000 | [diff] [blame] | 56 | | | __self__ | instance to which this | |
Georg Brandl | 55ac8f0 | 2007-09-01 13:51:09 +0000 | [diff] [blame] | 57 | | | | method is bound, or | |
| 58 | | | | ``None`` | |
| 59 | +-----------+-----------------+---------------------------+ |
| 60 | | function | __doc__ | documentation string | |
| 61 | +-----------+-----------------+---------------------------+ |
| 62 | | | __name__ | name with which this | |
| 63 | | | | function was defined | |
| 64 | +-----------+-----------------+---------------------------+ |
| 65 | | | __code__ | code object containing | |
| 66 | | | | compiled function | |
Georg Brandl | 9afde1c | 2007-11-01 20:32:30 +0000 | [diff] [blame] | 67 | | | | :term:`bytecode` | |
Georg Brandl | 55ac8f0 | 2007-09-01 13:51:09 +0000 | [diff] [blame] | 68 | +-----------+-----------------+---------------------------+ |
| 69 | | | __defaults__ | tuple of any default | |
| 70 | | | | values for arguments | |
| 71 | +-----------+-----------------+---------------------------+ |
| 72 | | | __globals__ | global namespace in which | |
| 73 | | | | this function was defined | |
| 74 | +-----------+-----------------+---------------------------+ |
| 75 | | traceback | tb_frame | frame object at this | |
| 76 | | | | level | |
| 77 | +-----------+-----------------+---------------------------+ |
| 78 | | | tb_lasti | index of last attempted | |
| 79 | | | | instruction in bytecode | |
| 80 | +-----------+-----------------+---------------------------+ |
| 81 | | | tb_lineno | current line number in | |
| 82 | | | | Python source code | |
| 83 | +-----------+-----------------+---------------------------+ |
| 84 | | | tb_next | next inner traceback | |
| 85 | | | | object (called by this | |
| 86 | | | | level) | |
| 87 | +-----------+-----------------+---------------------------+ |
| 88 | | frame | f_back | next outer frame object | |
| 89 | | | | (this frame's caller) | |
| 90 | +-----------+-----------------+---------------------------+ |
| 91 | | | f_builtins | built-in namespace seen | |
| 92 | | | | by this frame | |
| 93 | +-----------+-----------------+---------------------------+ |
| 94 | | | f_code | code object being | |
| 95 | | | | executed in this frame | |
| 96 | +-----------+-----------------+---------------------------+ |
Georg Brandl | 55ac8f0 | 2007-09-01 13:51:09 +0000 | [diff] [blame] | 97 | | | f_globals | global namespace seen by | |
| 98 | | | | this frame | |
| 99 | +-----------+-----------------+---------------------------+ |
| 100 | | | f_lasti | index of last attempted | |
| 101 | | | | instruction in bytecode | |
| 102 | +-----------+-----------------+---------------------------+ |
| 103 | | | f_lineno | current line number in | |
| 104 | | | | Python source code | |
| 105 | +-----------+-----------------+---------------------------+ |
| 106 | | | f_locals | local namespace seen by | |
| 107 | | | | this frame | |
| 108 | +-----------+-----------------+---------------------------+ |
| 109 | | | f_restricted | 0 or 1 if frame is in | |
| 110 | | | | restricted execution mode | |
| 111 | +-----------+-----------------+---------------------------+ |
| 112 | | | f_trace | tracing function for this | |
| 113 | | | | frame, or ``None`` | |
| 114 | +-----------+-----------------+---------------------------+ |
| 115 | | code | co_argcount | number of arguments (not | |
| 116 | | | | including \* or \*\* | |
| 117 | | | | args) | |
| 118 | +-----------+-----------------+---------------------------+ |
| 119 | | | co_code | string of raw compiled | |
| 120 | | | | bytecode | |
| 121 | +-----------+-----------------+---------------------------+ |
| 122 | | | co_consts | tuple of constants used | |
| 123 | | | | in the bytecode | |
| 124 | +-----------+-----------------+---------------------------+ |
| 125 | | | co_filename | name of file in which | |
| 126 | | | | this code object was | |
| 127 | | | | created | |
| 128 | +-----------+-----------------+---------------------------+ |
| 129 | | | co_firstlineno | number of first line in | |
| 130 | | | | Python source code | |
| 131 | +-----------+-----------------+---------------------------+ |
| 132 | | | co_flags | bitmap: 1=optimized ``|`` | |
| 133 | | | | 2=newlocals ``|`` 4=\*arg | |
| 134 | | | | ``|`` 8=\*\*arg | |
| 135 | +-----------+-----------------+---------------------------+ |
| 136 | | | co_lnotab | encoded mapping of line | |
| 137 | | | | numbers to bytecode | |
| 138 | | | | indices | |
| 139 | +-----------+-----------------+---------------------------+ |
| 140 | | | co_name | name with which this code | |
| 141 | | | | object was defined | |
| 142 | +-----------+-----------------+---------------------------+ |
| 143 | | | co_names | tuple of names of local | |
| 144 | | | | variables | |
| 145 | +-----------+-----------------+---------------------------+ |
| 146 | | | co_nlocals | number of local variables | |
| 147 | +-----------+-----------------+---------------------------+ |
| 148 | | | co_stacksize | virtual machine stack | |
| 149 | | | | space required | |
| 150 | +-----------+-----------------+---------------------------+ |
| 151 | | | co_varnames | tuple of names of | |
| 152 | | | | arguments and local | |
| 153 | | | | variables | |
| 154 | +-----------+-----------------+---------------------------+ |
| 155 | | builtin | __doc__ | documentation string | |
| 156 | +-----------+-----------------+---------------------------+ |
| 157 | | | __name__ | original name of this | |
| 158 | | | | function or method | |
| 159 | +-----------+-----------------+---------------------------+ |
| 160 | | | __self__ | instance to which a | |
| 161 | | | | method is bound, or | |
| 162 | | | | ``None`` | |
| 163 | +-----------+-----------------+---------------------------+ |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 164 | |
| 165 | |
| 166 | .. function:: getmembers(object[, predicate]) |
| 167 | |
| 168 | Return all the members of an object in a list of (name, value) pairs sorted by |
| 169 | name. If the optional *predicate* argument is supplied, only members for which |
| 170 | the predicate returns a true value are included. |
| 171 | |
Christian Heimes | 7f04431 | 2008-01-06 17:05:40 +0000 | [diff] [blame] | 172 | .. note:: |
| 173 | |
| 174 | :func:`getmembers` does not return metaclass attributes when the argument |
| 175 | is a class (this behavior is inherited from the :func:`dir` function). |
| 176 | |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 177 | |
| 178 | .. function:: getmoduleinfo(path) |
| 179 | |
Christian Heimes | 25bb783 | 2008-01-11 16:17:00 +0000 | [diff] [blame] | 180 | Returns a :term:`named tuple` ``ModuleInfo(name, suffix, mode, |
| 181 | module_type)`` of values that describe how Python will interpret the file |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 182 | identified by *path* if it is a module, or ``None`` if it would not be |
| 183 | identified as a module. The return tuple is ``(name, suffix, mode, mtype)``, |
| 184 | where *name* is the name of the module without the name of any enclosing |
| 185 | package, *suffix* is the trailing part of the file name (which may not be a |
| 186 | dot-delimited extension), *mode* is the :func:`open` mode that would be used |
| 187 | (``'r'`` or ``'rb'``), and *mtype* is an integer giving the type of the |
| 188 | module. *mtype* will have a value which can be compared to the constants |
| 189 | defined in the :mod:`imp` module; see the documentation for that module for |
| 190 | more information on module types. |
| 191 | |
| 192 | |
| 193 | .. function:: getmodulename(path) |
| 194 | |
| 195 | Return the name of the module named by the file *path*, without including the |
| 196 | names of enclosing packages. This uses the same algorithm as the interpreter |
| 197 | uses when searching for modules. If the name cannot be matched according to the |
| 198 | interpreter's rules, ``None`` is returned. |
| 199 | |
| 200 | |
| 201 | .. function:: ismodule(object) |
| 202 | |
| 203 | Return true if the object is a module. |
| 204 | |
| 205 | |
| 206 | .. function:: isclass(object) |
| 207 | |
| 208 | Return true if the object is a class. |
| 209 | |
| 210 | |
| 211 | .. function:: ismethod(object) |
| 212 | |
| 213 | Return true if the object is a method. |
| 214 | |
| 215 | |
| 216 | .. function:: isfunction(object) |
| 217 | |
Christian Heimes | d8654cf | 2007-12-02 15:22:16 +0000 | [diff] [blame] | 218 | Return true if the object is a Python function or unnamed (:term:`lambda`) function. |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 219 | |
| 220 | |
Christian Heimes | 7131fd9 | 2008-02-19 14:21:46 +0000 | [diff] [blame] | 221 | .. function:: isgeneratorfunction(object) |
| 222 | |
| 223 | Return true if the object is a Python generator function. |
| 224 | |
| 225 | |
| 226 | .. function:: isgenerator(object) |
| 227 | |
| 228 | Return true if the object is a generator. |
| 229 | |
| 230 | |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 231 | .. function:: istraceback(object) |
| 232 | |
| 233 | Return true if the object is a traceback. |
| 234 | |
| 235 | |
| 236 | .. function:: isframe(object) |
| 237 | |
| 238 | Return true if the object is a frame. |
| 239 | |
| 240 | |
| 241 | .. function:: iscode(object) |
| 242 | |
| 243 | Return true if the object is a code. |
| 244 | |
| 245 | |
| 246 | .. function:: isbuiltin(object) |
| 247 | |
| 248 | Return true if the object is a built-in function. |
| 249 | |
| 250 | |
| 251 | .. function:: isroutine(object) |
| 252 | |
| 253 | Return true if the object is a user-defined or built-in function or method. |
| 254 | |
Christian Heimes | be5b30b | 2008-03-03 19:18:51 +0000 | [diff] [blame] | 255 | .. function:: isabstract(object) |
| 256 | |
| 257 | Return true if the object is an abstract base class. |
| 258 | |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 259 | |
| 260 | .. function:: ismethoddescriptor(object) |
| 261 | |
Georg Brandl | 9afde1c | 2007-11-01 20:32:30 +0000 | [diff] [blame] | 262 | Return true if the object is a method descriptor, but not if :func:`ismethod` |
| 263 | or :func:`isclass` or :func:`isfunction` are true. |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 264 | |
Georg Brandl | e6bcc91 | 2008-05-12 18:05:20 +0000 | [diff] [blame] | 265 | This, for example, is true of ``int.__add__``. An object passing this test |
| 266 | has a :attr:`__get__` attribute but not a :attr:`__set__` attribute, but |
| 267 | beyond that the set of attributes varies. :attr:`__name__` is usually |
| 268 | sensible, and :attr:`__doc__` often is. |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 269 | |
Georg Brandl | 9afde1c | 2007-11-01 20:32:30 +0000 | [diff] [blame] | 270 | Methods implemented via descriptors that also pass one of the other tests |
| 271 | return false from the :func:`ismethoddescriptor` test, simply because the |
| 272 | other tests promise more -- you can, e.g., count on having the |
Christian Heimes | ff73795 | 2007-11-27 10:40:20 +0000 | [diff] [blame] | 273 | :attr:`__func__` attribute (etc) when an object passes :func:`ismethod`. |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 274 | |
| 275 | |
| 276 | .. function:: isdatadescriptor(object) |
| 277 | |
| 278 | Return true if the object is a data descriptor. |
| 279 | |
Georg Brandl | 9afde1c | 2007-11-01 20:32:30 +0000 | [diff] [blame] | 280 | Data descriptors have both a :attr:`__get__` and a :attr:`__set__` attribute. |
| 281 | Examples are properties (defined in Python), getsets, and members. The |
| 282 | latter two are defined in C and there are more specific tests available for |
| 283 | those types, which is robust across Python implementations. Typically, data |
| 284 | descriptors will also have :attr:`__name__` and :attr:`__doc__` attributes |
| 285 | (properties, getsets, and members have both of these attributes), but this is |
| 286 | not guaranteed. |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 287 | |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 288 | |
| 289 | .. function:: isgetsetdescriptor(object) |
| 290 | |
| 291 | Return true if the object is a getset descriptor. |
| 292 | |
| 293 | getsets are attributes defined in extension modules via ``PyGetSetDef`` |
| 294 | structures. For Python implementations without such types, this method will |
| 295 | always return ``False``. |
| 296 | |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 297 | |
| 298 | .. function:: ismemberdescriptor(object) |
| 299 | |
| 300 | Return true if the object is a member descriptor. |
| 301 | |
| 302 | Member descriptors are attributes defined in extension modules via |
Georg Brandl | 9afde1c | 2007-11-01 20:32:30 +0000 | [diff] [blame] | 303 | ``PyMemberDef`` structures. For Python implementations without such types, |
| 304 | this method will always return ``False``. |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 305 | |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 306 | |
| 307 | .. _inspect-source: |
| 308 | |
| 309 | Retrieving source code |
| 310 | ---------------------- |
| 311 | |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 312 | .. function:: getdoc(object) |
| 313 | |
Georg Brandl | 0c77a82 | 2008-06-10 16:37:50 +0000 | [diff] [blame] | 314 | Get the documentation string for an object, cleaned up with :func:`cleandoc`. |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 315 | |
| 316 | |
| 317 | .. function:: getcomments(object) |
| 318 | |
| 319 | Return in a single string any lines of comments immediately preceding the |
| 320 | object's source code (for a class, function, or method), or at the top of the |
| 321 | Python source file (if the object is a module). |
| 322 | |
| 323 | |
| 324 | .. function:: getfile(object) |
| 325 | |
| 326 | Return the name of the (text or binary) file in which an object was defined. |
| 327 | This will fail with a :exc:`TypeError` if the object is a built-in module, |
| 328 | class, or function. |
| 329 | |
| 330 | |
| 331 | .. function:: getmodule(object) |
| 332 | |
| 333 | Try to guess which module an object was defined in. |
| 334 | |
| 335 | |
| 336 | .. function:: getsourcefile(object) |
| 337 | |
| 338 | Return the name of the Python source file in which an object was defined. This |
| 339 | will fail with a :exc:`TypeError` if the object is a built-in module, class, or |
| 340 | function. |
| 341 | |
| 342 | |
| 343 | .. function:: getsourcelines(object) |
| 344 | |
| 345 | Return a list of source lines and starting line number for an object. The |
| 346 | argument may be a module, class, method, function, traceback, frame, or code |
| 347 | object. The source code is returned as a list of the lines corresponding to the |
| 348 | object and the line number indicates where in the original source file the first |
| 349 | line of code was found. An :exc:`IOError` is raised if the source code cannot |
| 350 | be retrieved. |
| 351 | |
| 352 | |
| 353 | .. function:: getsource(object) |
| 354 | |
| 355 | Return the text of the source code for an object. The argument may be a module, |
| 356 | class, method, function, traceback, frame, or code object. The source code is |
| 357 | returned as a single string. An :exc:`IOError` is raised if the source code |
| 358 | cannot be retrieved. |
| 359 | |
| 360 | |
Georg Brandl | 0c77a82 | 2008-06-10 16:37:50 +0000 | [diff] [blame] | 361 | .. function:: cleandoc(doc) |
| 362 | |
| 363 | Clean up indentation from docstrings that are indented to line up with blocks |
| 364 | of code. Any whitespace that can be uniformly removed from the second line |
| 365 | onwards is removed. Also, all tabs are expanded to spaces. |
| 366 | |
Georg Brandl | 0c77a82 | 2008-06-10 16:37:50 +0000 | [diff] [blame] | 367 | |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 368 | .. _inspect-classes-functions: |
| 369 | |
| 370 | Classes and functions |
| 371 | --------------------- |
| 372 | |
| 373 | |
| 374 | .. function:: getclasstree(classes[, unique]) |
| 375 | |
| 376 | Arrange the given list of classes into a hierarchy of nested lists. Where a |
| 377 | nested list appears, it contains classes derived from the class whose entry |
| 378 | immediately precedes the list. Each entry is a 2-tuple containing a class and a |
| 379 | tuple of its base classes. If the *unique* argument is true, exactly one entry |
| 380 | appears in the returned structure for each class in the given list. Otherwise, |
| 381 | classes using multiple inheritance and their descendants will appear multiple |
| 382 | times. |
| 383 | |
| 384 | |
| 385 | .. function:: getargspec(func) |
| 386 | |
Christian Heimes | 25bb783 | 2008-01-11 16:17:00 +0000 | [diff] [blame] | 387 | Get the names and default values of a function's arguments. A |
| 388 | :term:`named tuple` ``ArgSpec(args, varargs, keywords, |
| 389 | defaults)`` is returned. *args* is a list of |
Georg Brandl | 138bcb5 | 2007-09-12 19:04:21 +0000 | [diff] [blame] | 390 | the argument names. *varargs* and *varkw* are the names of the ``*`` and |
| 391 | ``**`` arguments or ``None``. *defaults* is a tuple of default argument |
| 392 | values or None if there are no default arguments; if this tuple has *n* |
| 393 | elements, they correspond to the last *n* elements listed in *args*. |
| 394 | |
| 395 | .. deprecated:: 3.0 |
| 396 | Use :func:`getfullargspec` instead, which provides information about |
Benjamin Peterson | 3e8e9cc | 2008-11-12 21:26:46 +0000 | [diff] [blame^] | 397 | keyword-only arguments and annotations. |
Georg Brandl | 138bcb5 | 2007-09-12 19:04:21 +0000 | [diff] [blame] | 398 | |
| 399 | |
| 400 | .. function:: getfullargspec(func) |
| 401 | |
Christian Heimes | 25bb783 | 2008-01-11 16:17:00 +0000 | [diff] [blame] | 402 | Get the names and default values of a function's arguments. A :term:`named tuple` |
| 403 | is returned: |
Georg Brandl | 138bcb5 | 2007-09-12 19:04:21 +0000 | [diff] [blame] | 404 | |
Christian Heimes | 25bb783 | 2008-01-11 16:17:00 +0000 | [diff] [blame] | 405 | ``FullArgSpec(args, varargs, varkw, defaults, kwonlyargs, kwonlydefaults, annotations)`` |
Georg Brandl | 138bcb5 | 2007-09-12 19:04:21 +0000 | [diff] [blame] | 406 | |
| 407 | *args* is a list of the argument names. *varargs* and *varkw* are the names |
| 408 | of the ``*`` and ``**`` arguments or ``None``. *defaults* is an n-tuple of |
| 409 | the default values of the last n arguments. *kwonlyargs* is a list of |
| 410 | keyword-only argument names. *kwonlydefaults* is a dictionary mapping names |
| 411 | from kwonlyargs to defaults. *annotations* is a dictionary mapping argument |
| 412 | names to annotations. |
| 413 | |
| 414 | The first four items in the tuple correspond to :func:`getargspec`. |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 415 | |
| 416 | |
| 417 | .. function:: getargvalues(frame) |
| 418 | |
Christian Heimes | 25bb783 | 2008-01-11 16:17:00 +0000 | [diff] [blame] | 419 | Get information about arguments passed into a particular frame. A :term:`named tuple` |
| 420 | ``ArgInfo(args, varargs, keywords, locals)`` is returned. *args* is a list of the |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 421 | argument names (it may contain nested lists). *varargs* and *varkw* are the |
| 422 | names of the ``*`` and ``**`` arguments or ``None``. *locals* is the locals |
| 423 | dictionary of the given frame. |
| 424 | |
| 425 | |
| 426 | .. function:: formatargspec(args[, varargs, varkw, defaults, formatarg, formatvarargs, formatvarkw, formatvalue, join]) |
| 427 | |
| 428 | Format a pretty argument spec from the four values returned by |
| 429 | :func:`getargspec`. The format\* arguments are the corresponding optional |
| 430 | formatting functions that are called to turn names and values into strings. |
| 431 | |
| 432 | |
| 433 | .. function:: formatargvalues(args[, varargs, varkw, locals, formatarg, formatvarargs, formatvarkw, formatvalue, join]) |
| 434 | |
| 435 | Format a pretty argument spec from the four values returned by |
| 436 | :func:`getargvalues`. The format\* arguments are the corresponding optional |
| 437 | formatting functions that are called to turn names and values into strings. |
| 438 | |
| 439 | |
| 440 | .. function:: getmro(cls) |
| 441 | |
| 442 | Return a tuple of class cls's base classes, including cls, in method resolution |
| 443 | order. No class appears more than once in this tuple. Note that the method |
| 444 | resolution order depends on cls's type. Unless a very peculiar user-defined |
| 445 | metatype is in use, cls will be the first element of the tuple. |
| 446 | |
| 447 | |
| 448 | .. _inspect-stack: |
| 449 | |
| 450 | The interpreter stack |
| 451 | --------------------- |
| 452 | |
| 453 | When the following functions return "frame records," each record is a tuple of |
| 454 | six items: the frame object, the filename, the line number of the current line, |
| 455 | the function name, a list of lines of context from the source code, and the |
| 456 | index of the current line within that list. |
| 457 | |
| 458 | .. warning:: |
| 459 | |
| 460 | Keeping references to frame objects, as found in the first element of the frame |
| 461 | records these functions return, can cause your program to create reference |
| 462 | cycles. Once a reference cycle has been created, the lifespan of all objects |
| 463 | which can be accessed from the objects which form the cycle can become much |
| 464 | longer even if Python's optional cycle detector is enabled. If such cycles must |
| 465 | be created, it is important to ensure they are explicitly broken to avoid the |
| 466 | delayed destruction of objects and increased memory consumption which occurs. |
| 467 | |
| 468 | Though the cycle detector will catch these, destruction of the frames (and local |
| 469 | variables) can be made deterministic by removing the cycle in a |
| 470 | :keyword:`finally` clause. This is also important if the cycle detector was |
| 471 | disabled when Python was compiled or using :func:`gc.disable`. For example:: |
| 472 | |
| 473 | def handle_stackframe_without_leak(): |
| 474 | frame = inspect.currentframe() |
| 475 | try: |
| 476 | # do something with the frame |
| 477 | finally: |
| 478 | del frame |
| 479 | |
| 480 | The optional *context* argument supported by most of these functions specifies |
| 481 | the number of lines of context to return, which are centered around the current |
| 482 | line. |
| 483 | |
| 484 | |
| 485 | .. function:: getframeinfo(frame[, context]) |
| 486 | |
Christian Heimes | 25bb783 | 2008-01-11 16:17:00 +0000 | [diff] [blame] | 487 | Get information about a frame or traceback object. A :term:`named tuple` |
| 488 | ``Traceback(filename, lineno, function, code_context, index)`` is returned. |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 489 | |
| 490 | |
| 491 | .. function:: getouterframes(frame[, context]) |
| 492 | |
| 493 | Get a list of frame records for a frame and all outer frames. These frames |
| 494 | represent the calls that lead to the creation of *frame*. The first entry in the |
| 495 | returned list represents *frame*; the last entry represents the outermost call |
| 496 | on *frame*'s stack. |
| 497 | |
| 498 | |
| 499 | .. function:: getinnerframes(traceback[, context]) |
| 500 | |
| 501 | Get a list of frame records for a traceback's frame and all inner frames. These |
| 502 | frames represent calls made as a consequence of *frame*. The first entry in the |
| 503 | list represents *traceback*; the last entry represents where the exception was |
| 504 | raised. |
| 505 | |
| 506 | |
| 507 | .. function:: currentframe() |
| 508 | |
| 509 | Return the frame object for the caller's stack frame. |
| 510 | |
| 511 | |
| 512 | .. function:: stack([context]) |
| 513 | |
| 514 | Return a list of frame records for the caller's stack. The first entry in the |
| 515 | returned list represents the caller; the last entry represents the outermost |
| 516 | call on the stack. |
| 517 | |
| 518 | |
| 519 | .. function:: trace([context]) |
| 520 | |
| 521 | Return a list of frame records for the stack between the current frame and the |
| 522 | frame in which an exception currently being handled was raised in. The first |
| 523 | entry in the list represents the caller; the last entry represents where the |
| 524 | exception was raised. |
| 525 | |