Lib/dos-8x3/exceptio.py

   1 """Class based built-in exception hierarchy.
   2
   3 This is a new feature whereby all the standard built-in exceptions,
   4 traditionally string objects, are replaced with classes.  This gives
   5 Python's exception handling mechanism a more object-oriented feel.
   6
   7 Most existing code should continue to work with class based
   8 exceptions.  Some tricky uses of IOError may break, but the most
   9 common uses should work.
  10
  11 To disable this feature, start the Python executable with the -X option.
  12
  13 Here is a rundown of the class hierarchy.  You can change this by
  14 editing this file, but it isn't recommended.  The classes with a `*'
  15 are new with this feature.  They are defined as tuples containing the
  16 derived exceptions when string-based exceptions are used.
  17
  18 Exception(*)
  19  |
  20  +-- StandardError(*)
  21       |
  22       +-- SystemExit
  23       +-- KeyboardInterrupt
  24       +-- ImportError
  25       +-- IOError
  26       +-- EOFError
  27       +-- RuntimeError
  28       +-- NameError
  29       +-- AttributeError
  30       +-- SyntaxError
  31       +-- TypeError
  32       +-- AssertionError
  33       +-- LookupError(*)
  34       |    |
  35       |    +-- IndexError
  36       |    +-- KeyError
  37       |
  38       +-- ArithmeticError(*)
  39       |    |
  40       |    +-- OverflowError
  41       |    +-- ZeroDivisionError
  42       |    +-- FloatingPointError
  43       |
  44       +-- ValueError
  45       +-- SystemError
  46       +-- MemoryError
  47 """
  48
  49 class Exception:
  50     def __init__(self, *args):
  51         self.args = args
  52
  53     def __str__(self):
  54         if not self.args:
  55             return ''
  56         elif len(self.args) == 1:
  57             return str(self.args[0])
  58         else:
  59             return str(self.args)
  60
  61     def __getitem__(self, i):
  62         return self.args[i]
  63
  64 class StandardError(Exception):
  65     pass
  66
  67 class SyntaxError(StandardError):
  68     filename = lineno = offset = text = None
  69     msg = ""
  70     def __init__(self, *args):
  71         self.args = args
  72         if len(self.args) >= 1:
  73             self.msg = self.args[0]
  74         if len(self.args) == 2:
  75             info = self.args[1]
  76             try:
  77                 self.filename, self.lineno, self.offset, self.text = info
  78             except:
  79                 pass
  80     def __str__(self):
  81         return str(self.msg)
  82
  83 class EnvironmentError(StandardError):
  84     """Base class for exceptions that occur outside the Python system.
  85     Primarily used as a base class for OSError and IOError."""
  86     def __init__(self, *args):
  87         self.args = args
  88         self.errno = None
  89         self.strerror = None
  90         self.filename = None
  91         if len(args) == 3:
  92             # open() errors give third argument which is the filename.  BUT,
  93             # so common in-place unpacking doesn't break, e.g.:
  94             #
  95             # except IOError, (errno, strerror):
  96             #
  97             # we hack args so that it only contains two items.  This also
  98             # means we need our own __str__() which prints out the filename
  99             # when it was supplied.
 100             self.errno, self.strerror, self.filename = args
 101             self.args = args[0:2]
 102         if len(args) == 2:
 103             # common case: PyErr_SetFromErrno()
 104             self.errno, self.strerror = args
 105
 106     def __str__(self):
 107         if self.filename is not None:
 108             return '[Errno %s] %s: %s' % (self.errno, self.strerror,
 109                                           repr(self.filename))
 110         elif self.errno and self.strerror:
 111             return '[Errno %s] %s' % (self.errno, self.strerror)
 112         else:
 113             return StandardError.__str__(self)
 114
 115 class IOError(EnvironmentError):
 116     pass
 117
 118 class OSError(EnvironmentError):
 119     """Used by the posix module."""
 120     pass
 121
 122 class RuntimeError(StandardError):
 123     pass
 124
 125 class SystemError(StandardError):
 126     pass
 127
 128 class EOFError(StandardError):
 129     pass
 130
 131 class ImportError(StandardError):
 132     pass
 133
 134 class TypeError(StandardError):
 135     pass
 136
 137 class ValueError(StandardError):
 138     pass
 139
 140 class KeyboardInterrupt(StandardError):
 141     pass
 142
 143 class AssertionError(StandardError):
 144     pass
 145
 146 class ArithmeticError(StandardError):
 147     pass
 148
 149 class OverflowError(ArithmeticError):
 150     pass
 151
 152 class FloatingPointError(ArithmeticError):
 153     pass
 154
 155 class ZeroDivisionError(ArithmeticError):
 156     pass
 157
 158 class LookupError(StandardError):
 159     pass
 160
 161 class IndexError(LookupError):
 162     pass
 163
 164 class KeyError(LookupError):
 165     pass
 166
 167 class AttributeError(StandardError):
 168     pass
 169
 170 class NameError(StandardError):
 171     pass
 172
 173 class MemoryError(StandardError):
 174     pass
 175
 176 class SystemExit(Exception):
 177     def __init__(self, *args):
 178         self.args = args
 179         if len(args) == 0:
 180             self.code = None
 181         elif len(args) == 1:
 182             self.code = args[0]
 183         else:
 184             self.code = args