Macro into_matrix_expr 

macro_rules! into_matrix_expr {
    () => { ... };
    (;$domain:expr) => { ... };
    ($x:expr) => { ... };
    ($x:expr;$domain:expr) => { ... };
}

Creates a new matrix as an Expression from a (Rust) vector, optionally with some index domain.

For usage details, see [into_matrix!].

To create a matrix expression from a list of elements, use matrix_expr!.