Method project_unchecked

crates/table/src/table.rs:1833–1858

Construct a projection of the row at `self` by extracting the `cols`. If `cols` contains zero or more than one column, the values of the projected columns are wrapped in a [`ProductValue`]. If `cols` is a single column, the value of that column is returned without wrapping in a `ProductValue`. # Safety - `cols` must not specify any column which is out-of-bounds for the row `self´.

(self, cols: &ColList)

    ///
    /// - `cols` must not specify any column which is out-of-bounds for the row `self´.
    pub unsafe fn project_unchecked(self, cols: &ColList) -> AlgebraicValue {
        let col_layouts = self.row_layout().product().elements;

        if let Some(head) = cols.as_singleton() {
            let head = head.idx();
            // SAFETY: caller promised that `head` is in-bounds of `col_layouts`.
            let col_layout = unsafe { col_layouts.get_unchecked(head) };
            // SAFETY:
            // - `col_layout` was just derived from the row layout.
            // - `AlgebraicValue` is compatible with any  `col_layout`.
            // - `self` is a valid row and offsetting to `col_layout` is valid.
            return unsafe { AlgebraicValue::unchecked_read_column(self, col_layout) };
        }
        let mut elements = Vec::with_capacity(cols.len() as usize);
        for col in cols.iter() {
            let col = col.idx();
            // SAFETY: caller promised that any `col` is in-bounds of `col_layouts`.
            let col_layout = unsafe { col_layouts.get_unchecked(col) };
            // SAFETY:
            // - `col_layout` was just derived from the row layout.
            // - `AlgebraicValue` is compatible with any  `col_layout`.
            // - `self` is a valid row and offsetting to `col_layout` is valid.
            elements.push(unsafe { AlgebraicValue::unchecked_read_column(self, col_layout) });
        }
        AlgebraicValue::product(elements)
    }

    /// Construct a projection of the row at `self` by extracting the `cols`.
    ///