57 lines
2.2 KiB
Python
57 lines
2.2 KiB
Python
"""Dump an AST into a string, with pythonic indentation.
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Based on Alex Leone's `astpp.py`, with changes to indentation logic.
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http://alexleone.blogspot.co.uk/2010/01/python-ast-pretty-printer.html
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"""
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__all__ = ["dump"]
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from ast import AST, iter_fields
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def dump(tree, *, include_attributes=False, multiline=True):
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"""Return a formatted dump of `tree`, as a string.
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`tree` can be an AST node or a statement suite (`list` of AST nodes).
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Attributes such as line numbers and column offsets are not dumped
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by default. If this is wanted, use `include_attributes=True`.
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To use indentation similar to how the code to construct the AST would
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appear as Python source code, use `multiline=True`.
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To put everything on one line, use `multiline=False`.
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Similar to `macropy`'s `real_repr`, but with indentation. The method
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`ast.AST.__repr__` itself can't be monkey-patched, because `ast.AST`
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is a built-in/extension type.
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"""
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def recurse(tree, previndent=0):
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def separator():
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if multiline:
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return f",\n{(previndent + moreindent) * ' '}"
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return ", "
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if isinstance(tree, AST):
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moreindent = len(f"{tree.__class__.__name__}(")
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fields = [(k, recurse(v, previndent + moreindent + len(f"{k}="))) for k, v in iter_fields(tree)]
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if include_attributes and tree._attributes:
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fields.extend([(k, recurse(getattr(tree, k, None), previndent + moreindent + len(f"{k}=")))
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for k in tree._attributes])
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return ''.join([
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tree.__class__.__name__,
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'(',
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separator().join((f'{k}={v}' for k, v in fields)),
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')'])
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elif isinstance(tree, list):
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moreindent = len("[")
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items = [recurse(elt, previndent + moreindent) for elt in tree]
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if items:
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items[0] = '[' + items[0].lstrip()
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items[-1] = items[-1] + ']'
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return separator().join(items)
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return '[]'
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return repr(tree)
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if not isinstance(tree, (AST, list)):
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raise TypeError(f'expected AST, got {tree.__class__.__name__!r}')
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return recurse(tree)
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