Teo and the elves are happy about your previous iteration of the EID program. They are submitting you a new system to implement with new rules.
Writing a system that parses
EID
We have already worked on it to design a program validating EIDs using T.D.D.
This time we will use a different approach.
Primitive obsession is a code smell in which primitive data types are used excessively to represent data models.
By excessively using primitive types:
- it is really hard to represent business concepts
- they can not contain any business logic
- this will disperse business logic throughout the system
During this new challenge you have to:
- Apply "Parse Don't Validate" principle.
- Use "Property-Based Testing" to drive the implementation.
- Use
Typesto representEID:Type-Driven Development
Your parsing function should ensure the below property:
for all (eid)
parseEID(eid.toString) == eid
With parse don't validate we want to make it impossible to represent an invalid EID in our system.
Your parser may look like this: String -> Either[ParsingError, EID]
The rules seen earlier still apply:
| Positions | Meaning | Possible values |
|---|---|---|
| 1 | Sex : 1 for Sloubi, 2 for Gagna, 3 for Catact |
1, 2 or 3 |
| 2, 3 | Last two digits of the year of birth (which gives the year to the nearest century) | From 00 to 99 |
| 4, 5, 6 | "Serial number": birth order | From 001 to 999 |
| 7, 8 | control key = complement to 97 of the number formed by the first 6 digits of the EID modulo 97 | From 01 to 97 |
Here is an example of such id:
