In vim, how do I redirect the output of a vimscript function?

Question

I have this vimscript function

 function! Env()
     redir => s
     sil! exe "norm!:ec$\<c-a>'\<c-b>\<right>\<right>\<del>'\<cr>"
     redir END
     return split(s)
 endfunction

This function was obtained from this question:
How to list all the environment variables in Vim?

When I do :call Env() I don't see any output, but :echo Env() displays as output the names of all environment variables.

I'd rather copy and paste this output somehow. I know about :redir. However this doesn't work:

:redir @A
:echo Env()
:redir END
"ap

Instead, a blank line is pasted.

I have tried many combinations of the :redir command (to registers and/or files) and variations on call Env() without success. Is this because the output generated is from calling a function? I thought it might be because the function returns a list, but :echo string(Env()) isn't captured by :redir either.

Edit: This is the modified solution I used from the answer below.

function! Env()
    redir => s
    sil! exe "norm!:ec$\<c-a>'\<c-b>\<right>\<right>\<del>'\<cr>"
    redir END
    let @s = string(split(s))
endfunction

One can then execute :call Env() and then "sp to paste.

related question:
How to redirect ex command output into current buffer or file?

This is a problem with `:redir` that's being discussed [on the vim_dev mailing list](https://groups.google.com/d/msg/vim_dev/H3Z3ChSUh_4/beZs6KzYdBsJ). In short, nested `:redir` isn't possible. — glts, May 18 '13 at 16:11
I edited my question --- is there a way to modify `Env()` to output, say, to a register or global variable that I can access after a `call Env()` command? — Ein, May 18 '13 at 16:19
Note that `:redir @A` *appends* to register "a. If you want to overwrite it, use lowercase: `:redir @a`. — Aaron Thoma, Dec 05 '16 at 15:40

score 2 · Accepted Answer · answered May 18 '13 at 16:33

As I said in the comment, this is a problem with :redir that's being discussed on vim_dev. In short, nested redirection with :redir isn't possible.

But of course you can simply modify your Env() function to redirect output to a register or global variable.

Just change redir => s to either redir => g:s (global variable g:s) or redir @s (register s), and remove the return statement. Let's use the register:

function! Env()
    redir @s
    sil! exe "norm!:ec$\<c-a>'\<c-b>\<right>\<right>\<del>'\<cr>"
    redir END
endfunction

After calling the function, the output is stored in register s and you can put it with "sp, of course.

Thank you. I modified this solution slightly to format the output before storing it in `@s` (as shown in the edit to my question). — Ein, May 18 '13 at 17:01

Aaron Thoma · Answer 2 · 2016-12-05T15:58:24.867

0

:let @a+=Env()

instead of

:redir @A
:echo Env()
:redir END

is much more concise, but doesn't print Env()'s output to the screen.

(The asker @Ein's modified solution does neither.)

edited Dec 05 '16 at 15:58

answered Dec 05 '16 at 15:39

Aaron Thoma

3,820
1
37
34

(Or `:let @A=` equivalently to `:let @a+=`.) – Aaron Thoma Dec 05 '16 at 15:59

In vim, how do I redirect the output of a vimscript function?

2 Answers2