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Python

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What it detects

• Functions: def (sync and async) becomes Function
• Classes: class_definition becomes Class; methods are Function nodes nested inside
• Decorators: decorator becomes Decorator; a decorated definition becomes a DecoratedDef wrapper around the underlying function or class
• Imports: import_statement, import_from_statement, and future_import_statement all become Import
• Assignments: assignment and augmented_assignment become Assignment / AugmentedAssignment. Python has no separate Variable concept. A variable’s name lives in the declarator of the assignment that binds it, not in a canonical label
• Control flow: if / elif / else, for / while, try / except / finally, with, match / case
• Comprehensions and lambdas: list / dict / set comprehensions, generator expressions, lambda
• Type annotations: type, generic_type, and union_type become TypeAnnotation / GenericType / UnionType

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Node type mapping

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Example: refactoring a Python module

TAX_RATE = 0.08

def apply_discount(price: float) -> float:
    return price * (1 - TAX_RATE)

def checkout(total: float) -> float:
    return apply_discount(total) + 2.99

TAX_RATE = 0.08
from discounts import apply_promo

def checkout(total: float) -> float:
    return apply_promo(total) + 2.99

def apply_promo(price: float, max_discount: float = 0.5) -> float:
    return price * (1 - max_discount)

  cross-file moves:
  → function `apply_discount` from pricing.py to discounts.py
  ~ renamed function `apply_discount` to `apply_promo`
  + added parameter `max_discount` in function `apply_promo`
  ~ changed value of return expression from `price * (1 - TAX_RATE)` to `price * (1 - max_discount)`
  ~ changed value of call expression from `apply_discount(total)` to `apply_promo(total)` in function `checkout`
4 modifications, 1 move

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Known limitations

• Methods are not distinct: there is no Method concept; a method is a Function nested in a Class.
• No Variable concept: plain assignments become Assignment, so a renamed variable shows up as a change in its declarator children, not on a canonical label.
• Decorated definitions wrap the definition: DecoratedDef is a wrapper node, so a decorator change and a body change are separate edits.
• Lambdas have no label: lambda becomes Lambda with no name.
• Unmapped node types pass through: anything outside the map keeps its raw tree-sitter type name.