Object to manage sys.displayhook. This came from IPython.core.kernel.display_hook, but is simplified (no callbacks or formatters) until more of the core is refactored.
| 30 | |
| 31 | |
| 32 | class DisplayTrap(Configurable): |
| 33 | """Object to manage sys.displayhook. |
| 34 | |
| 35 | This came from IPython.core.kernel.display_hook, but is simplified |
| 36 | (no callbacks or formatters) until more of the core is refactored. |
| 37 | """ |
| 38 | |
| 39 | hook = Any() |
| 40 | |
| 41 | def __init__(self, hook=None): |
| 42 | super(DisplayTrap, self).__init__(hook=hook, config=None) |
| 43 | self.old_hook = None |
| 44 | # We define this to track if a single BuiltinTrap is nested. |
| 45 | # Only turn off the trap when the outermost call to __exit__ is made. |
| 46 | self._nested_level = 0 |
| 47 | |
| 48 | def __enter__(self): |
| 49 | if self._nested_level == 0: |
| 50 | self.set() |
| 51 | self._nested_level += 1 |
| 52 | return self |
| 53 | |
| 54 | def __exit__(self, type, value, traceback): |
| 55 | if self._nested_level == 1: |
| 56 | self.unset() |
| 57 | self._nested_level -= 1 |
| 58 | # Returning False will cause exceptions to propagate |
| 59 | return False |
| 60 | |
| 61 | def set(self): |
| 62 | """Set the hook.""" |
| 63 | if sys.displayhook is not self.hook: |
| 64 | self.old_hook = sys.displayhook |
| 65 | sys.displayhook = self.hook |
| 66 | |
| 67 | def unset(self): |
| 68 | """Unset the hook.""" |
| 69 | sys.displayhook = self.old_hook |
| 70 |
no outgoing calls
no test coverage detected