# bare block "loop":

    {
        # head
        last
            if  ...;
        # body
    }
    # post

# vs goto:

    # top?
        # head
        goto END
            if  ...;
        # body
    END:
    # post

# vs if:

    # head
    if(  ! ...  ) {
        # body
    }
    # post