Copying a String to a Variable or a Register from Within a Function

Question

I want to write a function which copies, say, the last word of the next line which contains keyword into a variable say var or any named register say l.

I did something inelegant:

function! CopyIntoVar()
          "go to the next line which contains keyword
    /keyword

          "go to the last word and copy it like one does using normal mode
    normal $vb"ly
    let var=@l
endfunction

Is there a better way?

(I am not particularly interested in the last word. Just want to see how to copy a desired string into a register or variable).

Thanks.

Answer 1

I think you're looking for the expand() function:

Expand wildcards and the following special keywords in `{expr}`.

with the <cword> or <cWORD> special keywords:

<cword>     word under the cursor
<cWORD>     WORD under the cursor

Your function would then look like:

function! CopyIntoVar()
    " Go to the next line which contains keyword
    /keyword

    " Go to the last word
    normal $

    " Get the value of the word under the cursor
    let var = expand('<cword>')
endfunction

This still has 2 side-effects though:

• It will move the cursor
• Using / will set the "/ register (and pressing n now searches for that pattern).

This may or may not be what you want.

We can use the search() function to avoid setting "/, and use getpos() and setpos() to set & restore the cursor position:

Another advantage of search() it's not affected by settings such as wrapscan or magic; it always behaves the same.

function! CopyIntoVar()
    " Save cursor position
    let l:save_cursor = getpos(".")   

    " Go to the next line which contains keyword
    call search('keyword')

    " Go to the last word
    normal $

    " Get the value of the word under the cursor
    let var = expand('<cword>')

    " Restore cursor position
    call setpos('.', l:save_cursor)   
endfunction