Python Signature Lens

Display Haskell-style type signatures above Python functions using CodeLens.

Download here: https://marketplace.visualstudio.com/items?itemName=ubreblanca.python-signature-lens

Features

• Curried function signatures displayed above Python function definitions
• Supports generic type parameters and bounded constraints
• Handles class methods with inherited type parameters
• Works with async functions and multi-line signatures

Type Transformations

Python	Lens Displays
Optional[T]	T?
T | None	T?
None | T	T?
Union[A, B]	A | B
list[T]	[T]
dict[K, V]	{K: V}
set[T]	{T}
tuple[A, B, C]	(A, B, C)
Callable[[A, B], R]	(A -> B -> R)
Callable[[], R]	(() -> R)
"ForwardRef"	ForwardRef
*args: T	*T
**kwargs: T	**T

Configuration

Setting	Description	Default
pythonSignatureLens.enabled	Enable/disable signatures	true
pythonSignatureLens.showFunctionName	Show function name in signature	true
pythonSignatureLens.haskellStyleApplication	Use Haskell-style type application	false

Haskell-Style Type Application

When haskellStyleApplication is enabled, generic types use space-delimited syntax:

Python	Default	With haskellStyleApplication
Iterable[A]	Iterable[A]	Iterable A
Mapping[K, V]	Mapping[K, V]	Mapping K V
Iterator[Sequence[A]]	Iterator[Sequence[A]]	Iterator (Sequence A)