Recording In Vim

To record typed characters into register:
        q{0-9a-zA-Z"}
(uppercase to append).

To stop recording:
        q

To execute register content:
        @{0-9a-z".=*}
Note that register '%' (name of the current file) and '#' (name of the alternate file) cannot be used.

For "@=" you are prompted to enter an expression.  The result of the expression is then executed.