[TUHS] block operations in editors, was My EuroBSDcon talk

One might trace it to the founding tenet that a file is a stream of bytes, reinforced by the absence of multidemensional arrays in C. But it goes deeper than that. Ed imposes a structure, making a (finite) file into an array, aka list, of lines. It's easy to define block moves and copies in a list. But what are the semantics of a block move, wherein one treats the list as a ragged-right 2D array? What gets pushed aside? In what direction? How does a block move into column that not all destination rows reach? How do you cope when the bottom gets ragged? How about the top? Can one move blocks of tab-separated fields? I think everyone has rued the lack of block operations at one time or another. But implementing them in any degree of generality is a stumbling block. What should the semantics be? Ed's g command does that, except the sequence can't contain another g. Sam, barely harder than ed to learn, cures that deficiency and generalizes in other ways, too--but has no block operations. Doug