built in operators: srotate-left

srotate-left:
    description:
        srotate-left input-seq
        rotate the input sequence left one step

        srotate-left[n] input-seq
        rotate the input sequence left n steps, modulus size(input-seq)

    examples:
        srotate-left (|one> . |two> . |three> . |four> . |five>)
            |two> . |three> . |four> . |five> . |one>

        srotate-left[3] (|one> . |two> . |three> . |four> . |five>)
            |four> . |five> . |one> . |two> . |three>

        -- 11 mod 5 == 1, so rotate left 1 step:
        srotate-left[11] (|one> . |two> . |three> . |four> . |five>)
            |two> . |three> . |four> . |five> . |one>

    see also:
        srotate-right, rotate-right, rotate-left