17 Sep
2019
17 Sep
'19
6:42 a.m.
At 2019-09-16T20:20:32-0400, Doug McIlroy wrote:
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?
Just in case anyone didn't know, Vim has what it calls "visual block"
highlighting and operations. CTRL-V begins one and you use the usual
movement keys to shape and size it, then an operator like (y)ank or
(d)elete.
It won't always work as one expects because of the very questions that
Doug raises above.
Vim also has characterwise blocks (begin with 'v') and linewise blocks
(begin with 'V').
The last is, more than any other single factor, what pulled me over from
traditional vi (really nvi in my case). It was a big win over
line-counting with ":.,+n" expressions. In retrospect I should have
been smarter and just typed ":.,/pattern/", using as /pattern/ some
short string that did not appear in any of the lines I wanted to operate
on.
Though the vi clone with the best name was, indisputably, elvis.
Regards,
Branden