lua.lua

-- File: /home/sergio/.config/nvim/ftplugin/lua.lua
-- Last Change: Sat, 19 Feb 2022 15:58
-- source: https://www.reddit.com/r/neovim/comments/pl0p5v/shortcut_to_open_lua_require_file/

-- vim.opt_local.suffixesadd:prepend('.lua')
-- vim.opt_local.suffixesadd:prepend('init.lua')
-- vim.opt_local.path:prepend(vim.fn.stdpath('config')..'/lua')

local fmt = string.format

-- Iterator that splits a string o a given delimiter
local function split(str, delim)
    delim = delim or "%s"
    return string.gmatch(str, fmt('[^%s]+', delim))
end

-- Find the proper directory separator depending
-- on lua installation or OS.
local function dir_separator()
    -- Look at package.config for directory separator string (it's the first line)
    if package.config then
        return string.match(package.config, '^[^\n]')
    elseif vim.fn.has('win32') == 1 then
        return '\\'
    else
        return '/'
    end
end

-- Search for lua traditional include paths.
-- This mimics how require internally works.
local function include_paths(fname, ext)
    ext = ext or "lua"
    local sep = dir_separator()
    local paths = string.gsub(package.path, '%?', fname)
    for path in split(paths, "%;") do
        if vim.fn.filereadable(path) == 1 then
            return path
        end
    end
end

-- Search for nvim lua include paths
local function include_rtpaths(fname, ext)
    ext = ext or "lua"
    local sep = dir_separator()
    local rtpaths = vim.api.nvim_list_runtime_paths()
    local modfile, initfile = fmt('%s.%s', fname, ext), fmt('init.%s', ext)
    for _, path in ipairs(rtpaths) do
        -- Look on runtime path for 'lua/*.lua' files
        local path1 = table.concat({path, ext, modfile}, sep)
        if     vim.fn.filereadable(path1) == 1 then
            return path1
        end
        -- Look on runtime path for 'lua/*/init.lua' files
        local path2 = table.concat({path, ext, fname, initfile}, sep)
        if vim.fn.filereadable(path2) == 1 then
            return path2
        end
    end
end

-- Global function that searches the path for the required file
function find_required_path(module)
    -- Look at package.config for directory separator string (it's the first line)
    local sep = string.match(package.config, '^[^\n]')
    -- Properly change '.' to separator (probably '/' on *nix and '\' on Windows)
    local fname = vim.fn.substitute(module, "\\.", sep, "g")
    local f
    ---- First search for lua modules
    f = include_paths(fname, 'lua')
    if f then return f end
    -- This part is just for nvim modules
    f = include_rtpaths(fname, 'lua')
    if f then return f end
    ---- Now search for Fennel modules
    f = include_paths(fname, 'fnl')
    if f then return f end
    -- This part is just for nvim modules
    f = include_rtpaths(fname, 'fnl')
    if f then return f end
end


-- Set options to open require with gf
vim.opt_local.include = [=[\v<((do|load)file|require)\s*\(?['"]\zs[^'"]+\ze['"]]=]
vim.opt_local.includeexpr = "v:lua.find_required_path(v:fname)"