redis-om-python/redis_developer/model/render_tree.py
2021-10-19 15:06:50 -07:00

59 lines
2 KiB
Python

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