Derives: Custom behavior (Reference)

This page lists the dunder hooks used to customize derived behavior.

See also:

• Derives & traits
• Customize derived behavior (How-to)
• Stdlib traits

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Dunder hooks

Hook	Purpose
__str__	Display formatting ({value})
__eq__	Equality (==, !=)
__lt__	Ordering (<, sorting)
__hash__	Hashing (Set / Dict keys)

Rule:

• You must not combine a hook with the corresponding @derive(...) (conflict).

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Reflection helpers

Models and classes provide:

• __fields__() -> List[str]
• __class_name__() -> str

Example:

model User:
    name: str

def main() -> None:
    u = User(name="Alice")
    println(u.__class_name__())
    println(u.__fields__())