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Evaluator that wraps a user-provided function for dynamic evaluation. This class allows users to create evaluators from any callable function, automatically handling parameter passing, validation, and result conversion to Score objects. Key Features:
  • Dynamic Function Wrapping: Converts any callable into an evaluator
  • Argument Validation: Validates that provided arguments match function signature
  • Smart Result Conversion: Automatically converts various return types to Score
  • Error Handling: Gracefully handles function execution and argument errors
  • Parameter Flexibility: Supports functions with any parameter signature

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Parameters

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fn
Callable
required
The callable function to wrap as an evaluator.
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score_name
str | None
default:"None"
Optional custom name for the score. If not provided, uses the function name.

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Example

def equals(a, b):
        return a == b

    evaluator = EvalFn(equals, score_name="exact_match")
    score = evaluator.score(a="hello", b="hello")
    print(score.value)  # 1.0

    def length_check(text, min_length=5):
            return len(text) >= min_length

        evaluator = EvalFn(length_check)

        # Invalid arguments raise TypeError
        try:
                evaluator.score(wrong_param="value")
            except TypeError as e:
                    print(f"Error: {e}")

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property name

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score()

Execute the wrapped function and convert result to Score. Calls the wrapped function with the provided arguments and converts the result to a Score object. Validates that the provided arguments match the function’s signature.

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Parameters

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*args
Any
Positional arguments to pass to the wrapped function.
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**kwargs
Any
Keyword arguments to pass to the wrapped function. Only kwargs that match the function’s parameters are used.

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Returns

A Score object representing the function’s evaluation result.

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Raises

TypeError – If the provided arguments don’t match the function signature.
The function result is converted to a Score as follows:
  • bool: 1.0 for True, 0.0 for False
  • int/float: Direct value conversion
  • Score: Returns as-is