# Isogram

Determine if a word or phrase is an isogram.

An isogram (also known as a "nonpattern word") is a word or phrase without a repeating letter, however spaces and hyphens are allowed to appear multiple times.

Examples of isograms:

- lumberjacks
- background
- downstream
- six-year-old

The word *isograms*, however, is not an isogram, because the s repeats.

## Running the tests

To run the tests, run the command `busted .` from within the exercise directory.

## Further information

For more detailed information about the Lua track, including how to get help if
you're having trouble, please visit the exercism.io [Lua language page](http://exercism.io/languages/lua/about).

## Source

Wikipedia [https://en.wikipedia.org/wiki/Isogram](https://en.wikipedia.org/wiki/Isogram)

## Submitting Incomplete Solutions
It's possible to submit an incomplete solution so you can see how others have completed the exercise.