Minecraft Periodic Table

-- installer/updater for the periodic table program

local github = "https://raw.github.com/InputUsername/Periodic-table/master/files/"

local files = {
        "ptable.lua",
        "ptable_elements.lua",
        "ptable_extra.lua",
        "ptable_image",
        "ptable_legend"
}

fs.delete("/periodic_table")
fs.makeDir("/periodic_table")

local function getf(f)
        local getfile = http.get(github..f)
        if (getfile) then
                local contents = getfile.readAll()
                if (contents) then
                        if (string.find(f,"%.")) then
                                f = string.match(f,"(.+)%.")
                        end
                        local destination = fs.open("/periodic_table/"..f,"w")
                        destination.write(contents)
                        destination.close()
                        getfile.close()
                        return true
                else
                        getfile.close()
                        return nil,"error while installing "..f
                end
        else
                return nil,"error while downloading "..f
        end
end

local errors = 0

print("Welcome to the installer for Periodic table.")
print("This will download files from")
printError(github)
print()

for i=1,#files do
        local ok,err = getf(files[i],files[i])
        if not (ok) then
                printError(err)
                errors = errors+1
        else
                print("Installed "..files[i])
        end
end
print()

if (errors > 0) then
        printError("There were some errors during installation.")
        printError("Would you like to try again? [y/n]")
        while true do
                local e,c = os.pullEvent("char")
                if (c == "y" or c == "Y") then
                        return shell.run("/pt-update")
                else
                        return
                end
        end
end

print("Would you like to move the main program to the root directory? [y/n]")
while true do
        local e,c = os.pullEvent("char")
        if (c == "y" or c == "Y") then
                return fs.move("/periodic_table/ptable","/ptable")
        else
                break
        end
end