all Python 3astterm

ast.FunctionDef

functions and classes

The node for a def statement: name, args (an arguments node), body, decorator_list, returns, type_comment and, since 3.12, type_params.

Syntax

ast.FunctionDef(name, args, body, decorator_list, returns, type_comment, type_params)

async def is a different class, AsyncFunctionDef, and isinstance(node, ast.FunctionDef) misses it: check a tuple of both. lineno points at the def line, not the first decorator. The docstring is just the first Expr with a Constant in body; ast.get_docstring extracts it. The return annotation sits in returns as an expression node, not a string.

Examples

import ast
src = '@cache\ndef area(r: float) -> float:\n    "Площадь."\n    return 3.14 * r * r'
fn = ast.parse(src).body[0]
print(type(fn).__name__, fn.name, fn.lineno)  # → FunctionDef area 2
print(fn.decorator_list[0].id, fn.returns.id, fn.args.args[0].arg)  # → cache float r
print(ast.get_docstring(fn))  # → Площадь.

import ast
tree = ast.parse('def f(): pass\nasync def g(): pass')
print([n.name for n in tree.body if isinstance(n, ast.FunctionDef)])  # → ['f']

See also

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