Contents

return {
  valid = function(isbn)
    isbn = isbn:gsub('-', '')

    if not isbn:match('^%d%d%d%d%d%d%d%d%d[%dX]$') then
      return false
    end

    local sum = 0
    for i = 1, 10 do
      sum = sum + (11 - i) * (tonumber(isbn:sub(i, i)) or 10)
    end

    return sum % 11 == 0
  end
}

Version data entries

107 entries across 107 versions & 1 rubygems

Version	Path
trackler-2.2.1.180	tracks/lua/exercises/isbn-verifier/example.lua
trackler-2.2.1.179	tracks/lua/exercises/isbn-verifier/example.lua
trackler-2.2.1.178	tracks/lua/exercises/isbn-verifier/example.lua
trackler-2.2.1.177	tracks/lua/exercises/isbn-verifier/example.lua
trackler-2.2.1.176	tracks/lua/exercises/isbn-verifier/example.lua
trackler-2.2.1.175	tracks/lua/exercises/isbn-verifier/example.lua
trackler-2.2.1.174	tracks/lua/exercises/isbn-verifier/example.lua
trackler-2.2.1.173	tracks/lua/exercises/isbn-verifier/example.lua
trackler-2.2.1.172	tracks/lua/exercises/isbn-verifier/example.lua
trackler-2.2.1.171	tracks/lua/exercises/isbn-verifier/example.lua
trackler-2.2.1.170	tracks/lua/exercises/isbn-verifier/example.lua
trackler-2.2.1.169	tracks/lua/exercises/isbn-verifier/example.lua
trackler-2.2.1.167	tracks/lua/exercises/isbn-verifier/example.lua
trackler-2.2.1.166	tracks/lua/exercises/isbn-verifier/example.lua
trackler-2.2.1.165	tracks/lua/exercises/isbn-verifier/example.lua
trackler-2.2.1.164	tracks/lua/exercises/isbn-verifier/example.lua
trackler-2.2.1.163	tracks/lua/exercises/isbn-verifier/example.lua
trackler-2.2.1.162	tracks/lua/exercises/isbn-verifier/example.lua
trackler-2.2.1.161	tracks/lua/exercises/isbn-verifier/example.lua
trackler-2.2.1.160	tracks/lua/exercises/isbn-verifier/example.lua