tessl/pypi-crosshair-tool

Analyze Python code for correctness using symbolic execution and SMT solving to automatically find counterexamples for functions with type annotations and contracts.

1.24x

Overview

Eval results

Files

Generic Type Utilities

Name: tessl/pypi-crosshair-tool
Rating: 0.86 (1 reviews)
Author: tessl

A Python library providing utility functions that work with generic types and TypeVars. All functions include contracts that can be verified using symbolic execution.

Capabilities

Swaps elements in a typed pair

Swapping two elements of the same type in a tuple returns them in reversed order @test
Attempting to create a tuple with mismatched types for the same TypeVar parameter fails contract verification @test

Processes numeric values with type preservation

Multiplying numeric values preserves the input type (int stays int, float stays float) @test
Using bounded TypeVars correctly restricts inputs to specified types only @test

Retrieves and transforms generic list elements

Extracting the first element from a typed list returns the correct element type @test
Transforming a list with a default value maintains consistent element types throughout @test

Implementation

@generates

API

from typing import TypeVar, Tuple, List, Union

T = TypeVar('T')
NumericT = TypeVar('NumericT', int, float)

def swap_pair(pair: Tuple[T, T]) -> Tuple[T, T]:
    """
    Swaps the two elements in a pair tuple.

    pre: len(pair) == 2
    post: __return__[0] == pair[1] and __return__[1] == pair[0]
    """
    pass

def process_numeric(value: NumericT, multiplier: NumericT) -> NumericT:
    """
    Multiplies a numeric value by a multiplier of the same numeric type.

    pre: isinstance(value, (int, float)) and isinstance(multiplier, (int, float))
    post: isinstance(__return__, type(value))
    """
    pass

def get_first(items: List[T]) -> T:
    """
    Returns the first element from a non-empty list.

    pre: len(items) > 0
    post: __return__ == items[0]
    """
    pass

def transform_list(items: List[T], default: T) -> List[T]:
    """
    Transforms a list by replacing empty positions with a default value.
    Returns a list of the same type.

    pre: len(items) >= 0
    post: len(__return__) == len(items)
    post: all(isinstance(x, type(default)) for x in __return__)
    """
    pass

Dependencies { .dependencies }

crosshair-tool { .dependency }

Provides symbolic execution and contract verification capabilities for Python code.

Install with Tessl CLI

npx tessl i tessl/pypi-crosshair-tool