Neovim: Converting Vimscript Terminal Functions to Lua

Question

Author: @mizlan
Source: https://github.com/mizlan/vim-and-cp/blob/master/cp.vim#L16

This code adds charm to neovim integrated terminal.
For cpp programs, I have these: F9 compile, F10 run, F12 Compile and run

tnoremap <Esc> <C-\><C-n>
" https://vi.stackexchange.com/a/22327/36876
if has('nvim')
    augroup terminal_setup | au!
        autocmd TermOpen * nnoremap <buffer><LeftRelease> <LeftRelease>i
    augroup end
endif
function! TermWrapper(command) abort
    if !exists('g:split_term_style') | let g:split_term_style = 'vertical' | endif
    if g:split_term_style ==# 'vertical'
        let buffercmd = 'vnew'
    elseif g:split_term_style ==# 'horizontal'
        let buffercmd = 'new'
    else
        echoerr 'ERROR! g:split_term_style is not a valid value (must be ''horizontal'' or ''vertical'' but is currently set to ''' . g:split_term_style . ''')'
        throw 'ERROR! g:split_term_style is not a valid value (must be ''horizontal'' or ''vertical'')'
    endif
    exec buffercmd
    if exists('g:split_term_resize_cmd')
        exec g:split_term_resize_cmd
    endif
    exec 'term ' . a:command
    exec 'setlocal nornu nonu'
    exec 'startinsert'
endfunction
command! -nargs=0 Compile call TermWrapper(printf('g++ -std=c++17 -O2 -Wall %s -o %s.out', expand('%'), expand('%:r')))
autocmd FileType cpp nnoremap <F9> <Esc>:w <bar> Compile<CR>
command! -nargs=0 Run call TermWrapper(printf('./%s.out', expand('%:r')))
autocmd FileType cpp nnoremap <F10> :Run<CR>
command! -nargs=0 CompileAndRun call TermWrapper(printf('g++ -std=c++17 -O2 -Wall %s -o %s.out && ./%s.out', expand('%'), expand('%:r'), expand('%:r')))
autocmd FileType cpp nnoremap <F12> <Esc>:w <bar> CompileAndRun<CR>
let g:split_term_style = 'horizontal'
let g:split_term_resize_cmd = 'resize 30'
set splitbelow

This is my first try at Lua conversion. Some fixes would be appreciated.

vim.api.nvim_set_keymap('t', '<Esc>', '<C-\\><C-n>', { noremap = true })
if vim.fn.has('nvim') == 1 then
    vim.cmd[[
        augroup terminal_setup
            autocmd!
            autocmd TermOpen * nnoremap <buffer><LeftRelease> <LeftRelease>i
        augroup end
    ]]
end
function TermWrapper(command)
    if not vim.g.split_term_style then
        vim.g.split_term_style = 'vertical'
    end
    local buffercmd
    if vim.g.split_term_style == 'vertical' then
        buffercmd = 'vnew'
    elseif vim.g.split_term_style == 'horizontal' then
        buffercmd = 'new'
    else
        vim.api.nvim_err_writeln('ERROR! g:split_term_style is not a valid value (must be ''horizontal'' or ''vertical'' but is currently set to ''' .. vim.g.split_term_style .. ''')')
        error('ERROR! g:split_term_style is not a valid value (must be ''horizontal'' or ''vertical'')')
    end
    vim.cmd(buffercmd)
    if vim.g.split_term_resize_cmd then
        vim.cmd(vim.g.split_term_resize_cmd)
    end
    vim.cmd('term ' .. command)
    vim.cmd('setlocal nornu nonu')
    vim.cmd('startinsert')
end
vim.cmd('command! -nargs=0 Compile call TermWrapper(printf(''g++ -std=c++17 -O2 -Wall %s -o %s.out'', expand(''%''), expand(''%:r'')))')
vim.cmd('autocmd FileType cpp nnoremap <F9> <Esc>:w <bar> Compile<CR>')
vim.cmd('command! -nargs=0 Run call TermWrapper(printf(''./%s.out'', expand(''%:r'')))')
vim.cmd('autocmd FileType cpp nnoremap <F10> :Run<CR>')
vim.cmd('command! -nargs=0 CompileAndRun call TermWrapper(printf(''g++ -std=c++17 -O2 -Wall %s -o %s.out && ./%s.out'', expand(''%''), expand(''%:r''), expand(''%:r'')))')
vim.cmd('autocmd FileType cpp nnoremap <F12> <Esc>:w <bar> CompileAndRun<CR>')
vim.g.split_term_style = 'horizontal'
vim.g.split_term_resize_cmd = 'resize 30'
vim.opt.splitbelow = true

This error message is being displayed.

E5112: Error while creating lua chunk: /home/killerbee/.config/nvim/init.lua:64:
 ')' expected near ''horizontal''

If the vimscript function works, why do you need to convert it to lua? Just keep on using it, if you don't know how to convert it to lua — Christian Brabandt, Oct 11 '23 at 11:39

Vivian De Smedt · Accepted Answer · 2023-10-11T11:52:52.930

I would do that:

vim.api.nvim_set_keymap('t', '<Esc>', '<C-\\><C-n>', { noremap = true })
if vim.fn.has('nvim') == 1 then
    vim.cmd[[
        augroup terminal_setup
            autocmd!
            autocmd TermOpen * nnoremap <buffer><LeftRelease> <LeftRelease>i
        augroup end
    ]]
end
function TermWrapper(command)
    if not vim.g.split_term_style then
        vim.g.split_term_style = 'vertical'
    end
    local buffercmd
    if vim.g.split_term_style == 'vertical' then
        buffercmd = 'vnew'
    elseif vim.g.split_term_style == 'horizontal' then
        buffercmd = 'new'
    else
        vim.api.nvim_err_writeln("ERROR! g:split_term_style is not a valid value (must be 'horizontal' or 'vertical' but is currently set to '" .. vim.g.split_term_style .. "')")
        error("ERROR! g:split_term_style is not a valid value (must be 'horizontal' or 'vertical')")
    end
    vim.cmd(buffercmd)
    if vim.g.split_term_resize_cmd then
        vim.cmd(vim.g.split_term_resize_cmd)
    end
    vim.cmd('term ' .. command)
    vim.cmd('setlocal nornu nonu')
    vim.cmd('startinsert')
end
vim.cmd([[command! -nargs=0 Compile lua TermWrapper(string.format('g++ -std=c++17 -O2 -Wall %s -o %s.out', vim.fn.expand("%"), vim.fn.expand("%:r")))]])
vim.cmd('autocmd FileType cpp nnoremap <F9> <Esc>:w <bar> Compile<CR>')
vim.cmd([[command! -nargs=0 Run lua TermWrapper(string.format("./%s.out", vim.fn.expand("%:r")))]])
vim.cmd('autocmd FileType cpp nnoremap <F10> :Run<CR>')
vim.cmd([[command! -nargs=0 CompileAndRun lua TermWrapper(string.format('g++ -std=c++17 -O2 -Wall %s -o %s.out && ./%s.out', vim.fn.expand("%"), vim.fn.expand("%:r"), vim.fn.expand("%:r")))]])
vim.cmd('autocmd FileType cpp nnoremap <F12> <Esc>:w <bar> CompileAndRun<CR>')
vim.g.split_term_style = 'horizontal'
vim.g.split_term_resize_cmd = 'resize 30'
vim.opt.splitbelow = true

PS: Since it is unclear what it is supposed to do for me I couldn't test properly yet (but it runs).

Yep, it runs. To test it, write a .cpp program. With given vimscript code and commands, we can compile, run, compile & run the c++ program internally. — Mega Bang, Oct 11 '23 at 11:38
Thanks for the feedback. Here is a new version where the commands are defined successfully — Vivian De Smedt, Oct 11 '23 at 11:53
Wrong value sets the error message. Got it. Now, it is fool-proof. — Mega Bang, Oct 11 '23 at 12:38
I have to admit, I don't see much teaching here. These Q&A won't be reusable: future querents will have a hard time understanding the conversion or how it might apply to them. I appreciate that it takes less effort to just post the code, but it's not my favorite kind of answer. — D. Ben Knoble, Oct 11 '23 at 16:26

Neovim: Converting Vimscript Terminal Functions to Lua

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