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{"@context":"https://schema.org","@type":"DiscussionForumPosting","headline":"issue with display hook in base python repl","articleBody":"This only applies to the base `python` repl, everything works in `IPython` repls.\n\nIn discussion on https://github.com/matplotlib/matplotlib/commit/b2fbae76c738d5c24e559b98ed494e9b146c16aa  discovered that `sys.displayhook` only gets evaluated for expressions, not statements.\n\nThis means that things like\n\n``` python\nimport numpy\npass\na = b\n```\n\nwill not trigger the auto-redrawing.  This is particularly troubling because this mean\n\n``` python\nln, = ax.plot(...)\n```\n\nwill not trigger a re-draw, but\n\n``` python\nax.plot(...)\n```\n\nwill.\n\nDue to b2fbae76c738d5c24e559b98ed494e9b146c16aa, where we rely on the auto-redrawing to trigger the `pyplot` redrawing this means that many `pyplot` workflows in the normal repl are broken (as in things that used to auto-redraw no longer do).\n\nThe options I think are:\n1. figure out how to trigger a call back on statements (if this is possible, it is well hidden.  There may be a reason IPython completely re-wrote the execution handling)\n2. say we only support interactive plotting with the IPython repl (which is a major regression)\n3. revert the removal of `draw_if_interactive` which maintains some functions as 'special'\n\nI suspect that the answer is going to be both 2 and 3.  normal python shell keeps current functionality and gains _some_ new functionality, IPython picks up lots of new functionality, and the code base keeps this particular wart.\n","author":{"url":"https://github.com/tacaswell","@type":"Person","name":"tacaswell"},"datePublished":"2015-06-08T03:07:45.000Z","interactionStatistic":{"@type":"InteractionCounter","interactionType":"https://schema.org/CommentAction","userInteractionCount":4},"url":"https://github.com/4504/matplotlib/issues/4504"}