ruchy 4.1.1

A systems scripting language that transpiles to idiomatic Rust with extreme quality engineering
Documentation 
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//! Verification helper functions for mathematical reasoning

/// Check if an assertion is always false
pub(in crate::proving) fn is_always_false(_assertion: &str) -> bool {
    // Placeholder for detecting always-false assertions
    false
}

/// Check if an assertion is always true
pub(in crate::proving) fn is_always_true(_assertion: &str) -> bool {
    // Placeholder for detecting always-true assertions
    false
}

/// Find counterexample to conditional property
pub(in crate::proving) fn find_conditional_counterexample(
    _antecedent: &str,
    _consequent: &str,
) -> Option<String> {
    // Placeholder for finding counterexamples to conditionals
    None
}

/// Find counterexample to universal quantification
pub(in crate::proving) fn find_universal_counterexample(_assertion: &str) -> Option<String> {
    // Placeholder for finding counterexamples to universal quantifications
    None
}

/// Find witness for existential quantification
pub(in crate::proving) fn find_existential_witness(_assertion: &str) -> Option<String> {
    // Placeholder for finding witnesses to existential quantifications
    None
}

/// Evaluate a mathematical expression to a number
pub(in crate::proving) fn evaluate_expression(expr: &str) -> Option<f64> {
    expr.parse::<f64>()
        .ok()
        .or_else(|| try_binary_operation(expr))
}

fn try_binary_operation(expr: &str) -> Option<f64> {
    try_operation(expr, '+', |a, b| a + b)
        .or_else(|| try_operation(expr, '-', |a, b| a - b))
        .or_else(|| try_operation(expr, '*', |a, b| a * b))
}

fn try_operation<F>(expr: &str, op: char, compute: F) -> Option<f64>
where
    F: Fn(f64, f64) -> f64,
{
    if !expr.contains(op) {
        return None;
    }

    let parts: Vec<&str> = expr.split(op).collect();
    if parts.len() != 2 {
        return None;
    }

    let left = evaluate_expression(parts[0].trim())?;
    let right = evaluate_expression(parts[1].trim())?;
    Some(compute(left, right))
}

#[cfg(test)]
mod tests {
    use super::*;

    #[test]
    fn test_is_always_false() {
        assert!(!is_always_false("true"));
        assert!(!is_always_false("some assertion"));
    }

    #[test]
    fn test_is_always_true() {
        assert!(!is_always_true("false"));
        assert!(!is_always_true("some assertion"));
    }

    #[test]
    fn test_find_conditional_counterexample() {
        let result = find_conditional_counterexample("a", "b");
        assert!(result.is_none());
    }

    #[test]
    fn test_find_universal_counterexample() {
        let result = find_universal_counterexample("forall x, x > 0");
        assert!(result.is_none());
    }

    #[test]
    fn test_find_existential_witness() {
        let result = find_existential_witness("exists x, x > 0");
        assert!(result.is_none());
    }

    #[test]
    fn test_evaluate_expression_number() {
        assert_eq!(evaluate_expression("42"), Some(42.0));
        assert_eq!(evaluate_expression("3.14"), Some(3.14));
        assert_eq!(evaluate_expression("-5"), Some(-5.0));
    }

    #[test]
    fn test_evaluate_expression_addition() {
        assert_eq!(evaluate_expression("2 + 3"), Some(5.0));
        assert_eq!(evaluate_expression("10 + 5"), Some(15.0));
    }

    #[test]
    fn test_evaluate_expression_subtraction() {
        assert_eq!(evaluate_expression("5 - 3"), Some(2.0));
        assert_eq!(evaluate_expression("10 - 15"), Some(-5.0));
    }

    #[test]
    fn test_evaluate_expression_multiplication() {
        assert_eq!(evaluate_expression("4 * 3"), Some(12.0));
        assert_eq!(evaluate_expression("2 * 5"), Some(10.0));
    }

    #[test]
    fn test_evaluate_expression_invalid() {
        assert!(evaluate_expression("abc").is_none());
        assert!(evaluate_expression("x + y").is_none());
    }

    #[test]
    fn test_try_binary_operation_add() {
        assert_eq!(try_binary_operation("1 + 2"), Some(3.0));
    }

    #[test]
    fn test_try_binary_operation_sub() {
        assert_eq!(try_binary_operation("5 - 2"), Some(3.0));
    }

    #[test]
    fn test_try_binary_operation_mul() {
        assert_eq!(try_binary_operation("3 * 4"), Some(12.0));
    }

    #[test]
    fn test_try_operation_no_operator() {
        let result = try_operation("42", '+', |a, b| a + b);
        assert!(result.is_none());
    }

    #[test]
    fn test_try_operation_too_many_parts() {
        let result = try_operation("1 + 2 + 3", '+', |a, b| a + b);
        assert!(result.is_none());
    }

    #[test]
    fn test_try_operation_invalid_operands() {
        let result = try_operation("a + b", '+', |a, b| a + b);
        assert!(result.is_none());
    }
}