User-defined 1-qubit operation

``matrix'' command is acceptable both in the file-input mode and in the read-line mode; this is unlike the command ``define'' in the item 8 of Sec. 2.1. You may use your own matrix for 1-qubit operation by using the ``matrix'' command.
matrix A (a b)(c d);
matrix A=(a b)(c d);
Once you define it, it can be invoked as
A(bit labels);
* The ``bit labels'' is a string in the style of ``1-6'' (qubit 1 to qubit 6) and/or ``1 3 5'' (qubit 1, 3, and 5).