Files
example-code-2e/17-it-generator/tree/classtree/classtree.py
Luciano Ramalho f5e3cb8ad3 minor refactorings
2021-10-22 14:59:04 -03:00

76 lines
2.0 KiB
Python
Executable File

#!/usr/bin/env python3
from importlib import import_module
import sys
SP = '\N{SPACE}'
HLIN = '\N{BOX DRAWINGS LIGHT HORIZONTAL}' * 2 + SP # ──
VLIN = '\N{BOX DRAWINGS LIGHT VERTICAL}' + SP * 3 # │
TEE = '\N{BOX DRAWINGS LIGHT VERTICAL AND RIGHT}' + HLIN # ├──
ELBOW = '\N{BOX DRAWINGS LIGHT UP AND RIGHT}' + HLIN # └──
def subclasses(cls):
try:
return cls.__subclasses__()
except TypeError: # handle the `type` type
return cls.__subclasses__(cls)
def tree(cls, level=0, last_sibling=True):
yield cls, level, last_sibling
chidren = subclasses(cls)
if chidren:
last = chidren[-1]
for child in chidren:
yield from tree(child, level + 1, child is last)
def render_lines(tree_generator):
cls, _, _ = next(tree_generator)
yield cls.__name__
prefix = ''
for cls, level, last in tree_generator:
prefix = prefix[: 4 * (level - 1)]
prefix = prefix.replace(TEE, VLIN).replace(ELBOW, SP * 4)
prefix += ELBOW if last else TEE
yield prefix + cls.__name__
def draw(cls):
for line in render_lines(tree(cls)):
print(line)
def parse(name):
if '.' in name:
return name.rsplit('.', 1)
else:
return 'builtins', name
def main(name):
module_name, cls_name = parse(name)
try:
cls = getattr(import_module(module_name), cls_name)
except ModuleNotFoundError:
print(f'*** Could not import {module_name!r}.')
except AttributeError:
print(f'*** {cls_name!r} not found in {module_name!r}.')
else:
if isinstance(cls, type):
draw(cls)
else:
print(f'*** {cls_name!r} is not a class.')
if __name__ == '__main__':
if len(sys.argv) == 2:
main(sys.argv[1])
else:
print('Usage:'
f'\t{sys.argv[0]} Class # for builtin classes\n'
f'\t{sys.argv[0]} package.Class # for other classes'
)