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| PEP: 217 | |
| Title: Display Hook for Interactive Use | |
| Version: $Revision$ | |
| Last-Modified: $Date$ | |
| Author: moshez@zadka.site.co.il (Moshe Zadka) | |
| Status: Final | |
| Type: Standards Track | |
| Content-Type: text/x-rst | |
| Created: 31-Jul-2000 | |
| Python-Version: 2.1 | |
| Post-History: | |
| Abstract | |
| ======== | |
| Python's interactive mode is one of the implementation's great | |
| strengths -- being able to write expressions on the command line | |
| and get back a meaningful output. However, the output function | |
| cannot be all things to all people, and the current output | |
| function too often falls short of this goal. This PEP describes a | |
| way to provides alternatives to the built-in display function in | |
| Python, so users will have control over the output from the | |
| interactive interpreter. | |
| Interface | |
| ========= | |
| The current Python solution has worked for many users, and this | |
| should not break it. Therefore, in the default configuration, | |
| nothing will change in the REPL loop. To change the way the | |
| interpreter prints interactively entered expressions, users | |
| will have to rebind ``sys.displayhook`` to a callable object. | |
| The result of calling this object with the result of the | |
| interactively entered expression should be print-able, | |
| and this is what will be printed on ``sys.stdout``. | |
| Solution | |
| ======== | |
| The bytecode ``PRINT_EXPR`` will call ``sys.displayhook(POP())``. | |
| A ``displayhook()`` will be added to the sys builtin module, which is | |
| equivalent to:: | |
| import __builtin__ | |
| def displayhook(o): | |
| if o is None: | |
| return | |
| __builtin__._ = None | |
| print `o` | |
| __builtin__._ = o | |
| Jython Issues | |
| ============= | |
| The method ``Py.printResult`` will be similarly changed. | |
| .. | |
| Local Variables: | |
| mode: indented-text | |
| indent-tabs-mode: nil | |
| End: |