awesome-wm-nice/table.lua

--[[
    Courtesy of: http://lua-users.org/wiki/SaveTableToFile
]]
local function exportstring(s)
    return string.format("%q", s)
end

--  The Save Function
local function save(tbl, filename)
    local charS, charE = "   ", "\n"
    local file, err = io.open(filename, "wb")
    if err then
        return err
    end

    -- Initialize variables for save procedure
    local tables, lookup = { tbl }, { [tbl] = 1 }
    file:write("return {" .. charE)

    for idx, t in ipairs(tables) do
        file:write("-- Table: {" .. idx .. "}" .. charE)
        file:write("{" .. charE)
        local thandled = {}

        for i, v in ipairs(t) do
            thandled[i] = true
            local stype = type(v)
            -- only handle value
            if stype == "table" then
                if not lookup[v] then
                    table.insert(tables, v)
                    lookup[v] = #tables
                end
                file:write(charS .. "{" .. lookup[v] .. "}," .. charE)
            elseif stype == "string" then
                file:write(charS .. exportstring(v) .. "," .. charE)
            elseif stype == "number" then
                file:write(charS .. tostring(v) .. "," .. charE)
            end
        end

        for i, v in pairs(t) do
            -- escape handled values
            if not thandled[i] then
                local str = ""
                local stype = type(i)
                -- handle index
                if stype == "table" then
                    if not lookup[i] then
                        table.insert(tables, i)
                        lookup[i] = #tables
                    end
                    str = charS .. "[{" .. lookup[i] .. "}]="
                elseif stype == "string" then
                    str = charS .. "[" .. exportstring(i) .. "]="
                elseif stype == "number" then
                    str = charS .. "[" .. tostring(i) .. "]="
                end

                if str ~= "" then
                    stype = type(v)
                    -- handle value
                    if stype == "table" then
                        if not lookup[v] then
                            table.insert(tables, v)
                            lookup[v] = #tables
                        end
                        file:write(str .. "{" .. lookup[v] .. "}," .. charE)
                    elseif stype == "string" then
                        file:write(str .. exportstring(v) .. "," .. charE)
                    elseif stype == "number" then
                        file:write(str .. tostring(v) .. "," .. charE)
                    end
                end
            end
        end
        file:write("}," .. charE)
    end
    file:write "}"
    file:close()
end

--  The Load Function
local function load(sfile)
    local ftables, err = loadfile(sfile)
    if err then
        return nil, err
    end
    local tables = ftables()
    for idx = 1, #tables do
        local tolinki = {}
        for i, v in pairs(tables[idx]) do
            if type(v) == "table" then
                tables[idx][i] = tables[v[1]]
            end
            if type(i) == "table" and tables[i[1]] then
                table.insert(tolinki, { i, tables[i[1]] })
            end
        end
        -- link indices
        for _, v in ipairs(tolinki) do
            tables[idx][v[2]], tables[idx][v[1]] = tables[idx][v[1]], nil
        end
    end
    return tables[1]
end

return { save = save, load = load }