Question

Here is a sample of text that I’m working with:

Word1
Word2
...
Word4 / Word5 Word6
Word7
Word8 Word9 Word10 / Word11 Word12 Word13 Word14
Word15
Word16
...

I would like to transform it by splitting the lines containing
slash-separated chunks, so that the first chunk (preceding the slash)
gets the trailing words copied from the second chunk (following the
slash) to equalize the number of words in both lines resulting from
the chunks, if the former one has fewer words than the latter.

In other words, the desired transformation is to target the lines
consisting of two groups of words separated by a (space-surrounded)
slash character. The first group of words (preceding the slash) on
a target line has 1 to 3 words, but always fewer than the second
group.

Thus, the target lines have the following structure:

‹G₁› / ‹G₂› ‹G₃›

where ‹G₁› and
‹G₂› ‹G₃› (i.e.,
‹G₂› concatenated with ‹G₃›)
constitute the two aforementioned groups of words, with
‹G₂› standing for as many of the leading words of the
after-slash group as there are in the before-slash one, and
‹G₃› standing for the remaining words in the
after-slash group.

Such lines should be replaced with two lines, as follows:

‹G₁› ‹G₃›
‹G₂› ‹G₃›

For the above example, the desired result is as follows:

Word1
Word2
...
Word4 Word6
Word5 Word6
Word7
Word8 Word9 Word10 Word14
Word11 Word12 Word13 Word14
Word15
Word16
...

Could you please help me implement this transformation in Vim?

Answer 1

You can write a function to expand slash:

fun! ExpandSlash() range
    for i in range(a:firstline, a:lastline)
        let ws = split(getline(i))
        let idx = index(ws, '/')
        if idx==-1
            continue
        endif
        let h= join(ws[ : idx-1])
        let m= join(ws[idx+1 : 2*idx])
        let t= join(ws[2*idx+1 : ])
        call setline(i, h.' '.t.'/'.m.' '.t)
    endfor
endfun

---

:%call ExpandSlash()
:%s@/@\r@

---

before

1 2 3 / 4 5 6 7 8

after

1 2 3 7 8
4 5 6 7 8