etc/nvim/lua/filetypes.lua

vim.filetype.add({
	extension = {
		pmd = "markdown",
	},
})

vim.filetype.add({
	extension = {
		xgo = "tengo",
	},
})

createAutoCmd = vim.api.nvim_create_autocmd
--
-- Basic thing for compiling languages.
createAutoCmd({
	"BufNewFile",
	"BufRead",
},{
	pattern = "*.tengo,*.go,*.c,*.cc,*.C,*.cpp,*.rs,*.lua,*.sql,*.tengo,*.xgo,*.tpp",
	callback = function()
		local buf = vim.bo[vim.api.nvim_get_current_buf()]
		vim.o.expandtab = false
		vim.o.tabstop = 4
		vim.o.shiftwidth = 4
	end,
})

createAutoCmd({
	"BufNewFile",
	"BufRead",
},{
	pattern = "*.md,*.txt,*.js,*.jsx,*.scss"..
		",*.css,*.sass,*.htm,*.html,*.htmlx,*.tmpl"..
		",*.tpl,*.yml,*.yaml,*.toml,*.tml",
	callback = function()
		local buf = vim.bo[vim.api.nvim_get_current_buf()]
		buf.expandtab = true
		buf.shiftwidth=2
		buf.tabstop=4
		buf.softtabstop = 0
	end,
})

createAutoCmd({
	"BufNewFile",
	"BufRead",
},{
	pattern = "*.py,*.zig",
	callback = function()
		local buf = vim.bo[vim.api.nvim_get_current_buf()]
		buf.expandtab = true
		buf.shiftwidth=4
		buf.tabstop=4
		buf.softtabstop = 0
	end,
})