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import ast |
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import sys |
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class _CatchDisplay: |
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"""Class to temporarily catch sys.displayhook""" |
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def __init__(self): |
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self.output = None |
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def __enter__(self): |
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self.old_hook = sys.displayhook |
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sys.displayhook = self |
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return self |
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def __exit__(self, type, value, traceback): |
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sys.displayhook = self.old_hook |
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return False |
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def __call__(self, output): |
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self.output = output |
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def eval_block(code, namespace=None, filename="<string>"): |
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""" |
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Execute a multi-line block of code in the given namespace |
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If the final statement in the code is an expression, return |
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the result of the expression. |
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""" |
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tree = ast.parse(code, filename="<ast>", mode="exec") |
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if namespace is None: |
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namespace = {} |
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catch_display = _CatchDisplay() |
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if isinstance(tree.body[-1], ast.Expr): |
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to_exec, to_eval = tree.body[:-1], tree.body[-1:] |
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else: |
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to_exec, to_eval = tree.body, [] |
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for node in to_exec: |
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compiled = compile(ast.Module([node], []), filename=filename, mode="exec") |
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exec(compiled, namespace) |
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with catch_display: |
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for node in to_eval: |
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compiled = compile( |
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ast.Interactive([node]), filename=filename, mode="single" |
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) |
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exec(compiled, namespace) |
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return catch_display.output |
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