How to delete backwards word and leading whitespace in vim?

Question

I'm trying to remap option-backspace behave in vim in Mac OS X's Terminal app similarly to how it would behave in other Mac applications.

It should perform a backwards delete word, also deleting any leading whitespace characters.

The closest match I've been able to find so far is the db command, but this only deletes to the beginning of the word; it does not remove any leading whitespace.

Here are some examples of what I am trying to accomplish (| is the cursor position):

test text| here
" After hitting option-backspace:
test| here

test text |here
" After hitting option-backspace:
test| here

high-lighting| text
" After hitting option-backspace:
high-| text

midway throu|gh text
" After hitting option-backspace:
midway|gh text

start |of line
" After hitting option-backspace:
|of line

I initially was going to do dbdh, but in the case of the third example, this would not work (the hyphen character is not whitespace, so it should be preserved).

Is there a good way to accomplish this?

EDIT: After doing some more typing, I realized that the "delete leading whitespace" behavior is actually not Mac-like; on my Mac, pressing option-backspace stops at the first non-word character, just like Vim does.

Thank you for joining me on this thought experiment, though (:

Answer 1

I have no access to a Mac, but I think this does almost, but not quite what you want (it doesn't place the cursor where you indicate in example two):

" Control-backspace works like control-w:
imap <c-backspace> <c-w>

Just change the mapping to use option instead of control.

You may also want/need to do:

:set backspace=indent,eol,start

See:

:help i_ctrl-w
:help 'backspace'

Answer 2

test text| here
" After hitting option-backspace:
test| here

test text |here
" After hitting option-backspace:
test| here

The cursor is supposed to be ON a character not between. So I don't really see the difference here. d?<Space> seems to do the trick, though. Or dbx, maybe.

high-lighting| text
" After hitting option-backspace:
high-| text

db works.

start |of line
" After hitting option-backspace:
|of line

If the cursor is On the space, d^. or d^x.

Answer 3

I discovered one method that almost works:

imap ^[^? <esc>bdw<insert>

(^[^? is what Terminal sends when I press option-backspace)

This backs the cursor up to the start of the previous word and deletes the following word, which also appears to include trailing whitespace.

As expected:

test text| here
" After hitting option-backspace:
test| here

There are two problems with it, though:

high-lighting| text
" After hitting option-backspace:
high|- text
" Expected:
high-| text

test te|xt here
" After hitting option-backspace:
test| here
" Expected:
"test|xt here"