exercism/elixir/german-sysadmin/HINTS.md

Hints

General

• Read about charlists, Unicode and code points, and case in the official Getting Started guide.
• Read about charlists and case on elixirschool.com.

1. Sanitize existing usernames by removing everything but lowercase letters

• Use recursion to iterate over a charlist.
• There is a built-in function that allows us to compare a given value against many patterns.
• There is a special syntax for getting a character's code point. It can be used in guards.
• Charlists are lists of code points, and code points, being numbers, can be compared to one another.
• Lowercase Latin letters all have consecutive code points, in alphabetical order.
• There is a built-in function that allows you to concatenate two lists.

2. Allow underscores

• There is a special syntax for getting a character's code point. It can be used in guards and it works for punctuation characters too.
• There is a built-in function that allows you to concatenate two lists.

3. Substitute German characters

• There is a special syntax for getting a character's code point. It can be used in guards and it works for non-Latin letters too.
• There is a built-in function that allows you to concatenate two lists.