48 lines
1.6 KiB
Python
48 lines
1.6 KiB
Python
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from dataclasses import dataclass
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from typing import Iterator, TypeVar, Union
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from black.nodes import Visitor
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from black.output import out
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from black.parsing import lib2to3_parse
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from blib2to3.pgen2 import token
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from blib2to3.pytree import Leaf, Node, type_repr
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LN = Union[Leaf, Node]
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T = TypeVar("T")
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@dataclass
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class DebugVisitor(Visitor[T]):
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tree_depth: int = 0
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def visit_default(self, node: LN) -> Iterator[T]:
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indent = " " * (2 * self.tree_depth)
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if isinstance(node, Node):
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_type = type_repr(node.type)
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out(f"{indent}{_type}", fg="yellow")
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self.tree_depth += 1
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for child in node.children:
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yield from self.visit(child)
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self.tree_depth -= 1
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out(f"{indent}/{_type}", fg="yellow", bold=False)
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else:
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_type = token.tok_name.get(node.type, str(node.type))
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out(f"{indent}{_type}", fg="blue", nl=False)
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if node.prefix:
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# We don't have to handle prefixes for `Node` objects since
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# that delegates to the first child anyway.
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out(f" {node.prefix!r}", fg="green", bold=False, nl=False)
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out(f" {node.value!r}", fg="blue", bold=False)
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@classmethod
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def show(cls, code: Union[str, Leaf, Node]) -> None:
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"""Pretty-print the lib2to3 AST of a given string of `code`.
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Convenience method for debugging.
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"""
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v: DebugVisitor[None] = DebugVisitor()
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if isinstance(code, str):
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code = lib2to3_parse(code)
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list(v.visit(code))
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