Function array_position

src/expr/src/scalar/func/variadic.rs:401–427

(
    array: Array<'a>,
    search: Datum<'a>,
    initial_pos: OptionalArg<Option<i32>>,
)

#[sqlfunc]
fn array_position<'a>(
    array: Array<'a>,
    search: Datum<'a>,
    initial_pos: OptionalArg<Option<i32>>,
) -> Result<Option<i32>, EvalError> {
    if array.dims().len() > 1 {
        return Err(EvalError::MultiDimensionalArraySearch);
    }

    if search == Datum::Null {
        return Ok(None);
    }

    let skip = match initial_pos.0 {
        None => 0,
        Some(None) => return Err(EvalError::MustNotBeNull("initial position".into())),
        Some(Some(o)) => usize::try_from(o).unwrap_or(0).saturating_sub(1),
    };

    let Some(r) = array.elements().iter().skip(skip).position(|d| d == search) else {
        return Ok(None);
    };

    // Adjust count for the amount we skipped, plus 1 for adjusting to PG indexing scheme.
    let p = i32::try_from(r + skip + 1).expect("fewer than i32::MAX elements in array");
    Ok(Some(p))
}

#[derive(
    Ord,