instructions.md

In this exercise you will implement a partial set of utility routines to help a developer clean up identifier names.

In the 4 tasks you will gradually build up the routine Clean A valid identifier comprises zero or more letters and underscores.

In all cases the input string is guaranteed to be non-null. If an empty string is passed to the Clean function, an empty string should be returned.

Note that the caller should avoid calling the routine Clean with an empty identifier since such identifiers are ineffectual.

1. Replace any spaces encountered with underscores

Implement the (static) Identifier.Clean() method to replace any spaces with underscores. This also applies to leading and trailing spaces.

Identifier.Clean("my   Id");
// => "my___Id"

2. Replace control characters with the upper case string "CTRL"

Modify the (static) Identifier.Clean() method to replace control characters with the upper case string "CTRL".

Identifier.Clean("my\0Id");
// => "myCTRLId",

3. Convert kebab-case to camelCase

Modify the (static) Identifier.Clean() method to convert kebab-case to camelCase.

Identifier.Clean("à-ḃç");
// => "àḂç"

4. Omit Greek lower case letters

Modify the (static) Identifier.Clean() method to omit any Greek letters in the range 'α' to 'ω'.

Identifier.Clean("MyΟβιεγτFinder");
// => "MyΟFinder"