59 lines
2 KiB
Python
59 lines
2 KiB
Python
"""
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This code adapted from the library "pptree," Copyright (c) 2017 Clément Michard
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and released under the MIT license: https://github.com/clemtoy/pptree
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"""
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import io
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def render_tree(current_node, nameattr='name', left_child='left',
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right_child='right', indent='', last='updown',
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buffer=None):
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"""Print a tree-like structure, `current_node`.
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This is a mostly-direct-copy of the print_tree() function from the ppbtree
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module of the pptree library, but instead of printing to standard out, we
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write to a StringIO buffer, then use that buffer to accumulate written lines
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during recursive calls to render_tree().
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"""
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if buffer is None:
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buffer = io.StringIO()
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if hasattr(current_node, nameattr):
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name = lambda node: getattr(node, nameattr)
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else:
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name = lambda node: str(node)
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up = getattr(current_node, left_child, None)
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down = getattr(current_node, right_child, None)
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if up is not None:
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next_last = 'up'
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next_indent = '{0}{1}{2}'.format(indent, ' ' if 'up' in last else '|', ' ' * len(str(name(current_node))))
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render_tree(up, nameattr, left_child, right_child, next_indent, next_last, buffer)
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if last == 'up':
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start_shape = '┌'
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elif last == 'down':
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start_shape = '└'
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elif last == 'updown':
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start_shape = ' '
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else:
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start_shape = '├'
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if up is not None and down is not None:
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end_shape = '┤'
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elif up:
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end_shape = '┘'
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elif down:
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end_shape = '┐'
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else:
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end_shape = ''
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print('{0}{1}{2}{3}'.format(indent, start_shape, name(current_node), end_shape),
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file=buffer)
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if down is not None:
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next_last = 'down'
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next_indent = '{0}{1}{2}'.format(indent, ' ' if 'down' in last else '|', ' ' * len(str(name(current_node))))
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render_tree(down, nameattr, left_child, right_child, next_indent, next_last, buffer)
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return f"\n{buffer.getvalue()}" |