blog/content/posts/vim-stt.md

---
title: Vim Send To Terminal
date: 2023-07-26T15:23:22-04:00
asciinema: true
tags:
    - vim
categories:
    - development
---

### Semi automatic scripts with vim `:terminal`

<!--more-->

Sometimes, fully automating a task is not worth the effort. So I end up running
a set of commands usually from a cheat sheet text file slightly modifying the
arguments each time. I used the below in vim to send line under cursor to vim's
`:terminal` open in a split 
```vim
:call term_list()[0]->term_sendkeys(getline('.') .. "\<CR>")
```
To send another line `@:` and then for every other line `@@`.  This works because, last
command run is stored in `register :` and the last macro executed using `@` is
stored in `register @`.

To do the same another day, `:call te<UP arrow>` to recall from vim's command
history. Or better, add a function and mapping.

```vim
def SendToTerminal()
    if term_list()->empty()
        echomsg "No Terminal windows found"
        return
    endif
    terms[0]->term_sendkeys(getline(.) .. "\<CR>")
enddef

nnoremap <silent><leader>s call SendToTerminal()<CR>
```

### More cool features

For most use-cases that was enough. However added a few more nice features
which is very helpful when you need it

1. Support sending a range of lines (visual selection) at a time. E.g. Send a
   function block to a python shell
2. Add a delay between lines in milliseconds. This is useful when the previous
   command reads from standard input and takes some time to complete
3. Support sending `ctrl` characters like `ctrl d`, `ctrl c` etc,

```vim
def g:SendRangeToTerminal(start_line: number, end_line: number)
    const terms = term_list()
    if terms->empty()
        echomsg "No Terminal windows found"
        return
    endif
    var line_num = start_line
    for line in getline(start_line, end_line)
        line_num += 1
        const spl_cmd = line->matchlist('\vVIMST (sleep|ctrl) ([0-9]+|[a-z])')
        if !spl_cmd->empty()
            const [_, cmd, arg1; _] = spl_cmd
            if cmd == "sleep"
                timer_start(str2nr(arg1), (_) => g:SendRangeToTerminal(line_num, end_line))
                return
            elseif cmd == "ctrl"
                terms[0]->term_sendkeys(nr2char(char2nr(arg1) - 96))
                continue
            endif
        endif
        terms[0]->term_sendkeys(line .. "\<CR>")
    endfor
enddef

command -range -bar SendToTerm :call g:SendRangeToTerminal(<line1>, <line2>)
vnoremap <silent><leader>s :SendToTerm<CR>
nnoremap <silent><leader>s :SendToTerm<CR>
```

### More cool mapping

Wouldn't it be nice to just double-click commands with mouse? Like a simple GUI! ;)

```vim
nnoremap <silent><2-LeftMouse> :SendToTerm<CR>
```

Or just hit `Enter`?

```vim
nnoremap <buffer> <CR> :SendToTerm \| norm j<CR>
```

Automatically add those mappings for `cheat.sh`
```vim
autocmd BufNewFile,BufRead cheat.sh nnoremap <buffer> <CR> :SendToTerm \| norm j<CR>
autocmd BufNewFile,BufRead cheat.sh nnoremap <buffer> <silent><2-LeftMouse> :SendToTerm<CR>
```

### Demo

{{< asciinema key="vimstt" >}}

### Using

Copying above snippets to your vimrc should work in a recent vim. Checked in
ubuntu 22.04 and archlinux. Git: [repo](https://gitea.balki.me/balki/vimfun/src/branch/main/stt/stt8.vim)

### neovim/tmux/screen

Since neovim uses a different terminal API, above snippets don't work in
neovim. [vim-slime](https://github.com/jpalardy/vim-slime) plugin (available
since 2007!) supports different types of terminal. However it does not support
adding delay and `ctrl` characters in text.