kommersbuch/src/songs.lua

require "lfs"

local open = io.open

local function read_file(path)
    local file = open(path, "rb") -- r read mode and b binary mode
    if not file then return nil end
    local content = file:read "*a" -- *a or *all reads the whole file
    file:close()
    return content
end

function string.ends(String,End)
    return End=='' or string.sub(String,-string.len(End))==End
end

function find_songs(dir)
    local files = {}
    for file in lfs.dir(dir) do
      table.insert(files, file)
    end
    table.sort(files)

    for i = 1, #files do
        local file = files[i]
        if string.ends(file, ".ly") then
            local ly_content = read_file(dir .. '/' .. file)
            local ly_title = string.match(ly_content, 'title = "(.-)"')

            tex.sprint('\\unchapter{' .. ly_title .. '}')
            tex.sprint('\\lilypondfile{' .. dir .. '/' .. file .. '}')
            tex.sprint('~\\\\')
            tex.sprint('~\\\\')
            tex.sprint('\\input{' .. dir .. '/' .. file:gsub("%.ly", ".tex") .. '}')
        end
    end
end