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https://github.com/philippus/julius
♊️ Roman Numerals library in Scala
https://github.com/philippus/julius
roman-numerals scala
Last synced: 27 days ago
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♊️ Roman Numerals library in Scala
- Host: GitHub
- URL: https://github.com/philippus/julius
- Owner: Philippus
- License: mpl-2.0
- Created: 2016-11-20T11:00:43.000Z (almost 8 years ago)
- Default Branch: main
- Last Pushed: 2024-09-16T18:30:25.000Z (about 2 months ago)
- Last Synced: 2024-09-16T23:24:08.139Z (about 2 months ago)
- Topics: roman-numerals, scala
- Language: Scala
- Homepage:
- Size: 429 KB
- Stars: 2
- Watchers: 4
- Forks: 1
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
- License: LICENSE
Awesome Lists containing this project
README
# Julius - Roman Numerals
[](https://github.com/Philippus/julius/actions/workflows/scala.yml?query=workflow%3Abuild+branch%3Amain)
[](https://codecov.io/gh/Philippus/julius)
[](https://scala-steward.org)
[](LICENSE)
Julius is a library for working with Roman Numerals in Scala.
It was started to get more comfortable with functional programming, Scala and property based testing.
It aims to:
- provide a pleasant API to the users of the library.
- provide the basic operations of addition, subtraction, multiplication and division.
- do as the Romans do: the implemented algorithms are only allowed to manipulate the Roman symbols directly, so no
converting back and forth from integers.
- use idiomatic Scala
- use functional style of programming
- use property based testing with ScalaCheck
## Installation
Julius is published for Scala 2.13 and Scala 3. To start using it add the following to your `build.sbt`:
```
libraryDependencies += "nl.gn0s1s" %% "julius" % "1.2.0"
```
## Specification
A Roman Numeral is either the value `nulla` (Latin for "none") or consists of one or more Roman Digits:
```
romanNumeral ::= nulla | romanDigit {romanDigit}
romanDigit ::= 'M' | 'D' | 'C' | 'L' | 'X' | 'V' | 'I'
```
## Constructing a Roman Numeral
There are several ways to construct a Roman Numeral.
Directly, by supplying a `List[RomanDigit]` to `RomanNumeral()`. This list is treated as an unordered collection of
Roman Digits.
After importing `RomanNumeral.RomanNumeralFromInt` or `RomanNumeral.RomanNumeralFromString` the following ways are
available:
Using the method `toRomanNumeral` on `Int` (resulting in a `RomanNumeral`) or `String` which will result in an
`Option[RomanNumeral]`.
Note that this last method expects compacted Roman Numerals (f.e. IV instead of IIII).
```scala
import nl.gn0s1s.julius.RomanDigit._
import nl.gn0s1s.julius.RomanNumeral
RomanNumeral(List(I, I, X, I)) // res0: RomanNumeral = XIII
import nl.gn0s1s.julius.RomanNumeral.RomanNumeralFromInt
1666.toRomanNumeral // res1: RomanNumeral = MDCLXVI
import nl.gn0s1s.julius.RomanNumeral.RomanNumeralFromString
"XIV".toRomanNumeral // res2: Option[RomanNumeral] = Some(XIV)
```
## Nulla
The special value `nulla` (zero) can also be constructed similarly:
```scala
import nl.gn0s1s.julius.RomanNumeral
RomanNumeral() // res3: RomanNumeral = nulla
import nl.gn0s1s.julius.RomanNumeral.RomanNumeralFromInt
0.toRomanNumeral // res4: RomanNumeral = nulla
import nl.gn0s1s.julius.RomanNumeral.RomanNumeralFromString
"nulla".toRomanNumeral // res5: Option[RomanNumeral] = Some(nulla)
```
## Operators and expressions
Julius makes the `+`, `-`, `*` and `/` operators available for Roman Digits and Numerals, which can be freely combined
to construct expressions. This is also yet another way to construct a Roman Numeral.
some examples:
```scala
import nl.gn0s1s.julius.RomanDigit._
import nl.gn0s1s.julius.RomanNumeral.RomanNumeralOps
M + M + X + V + I // res6: RomanNumeral = MMXVI
import nl.gn0s1s.julius.RomanNumeral.RomanNumeralFromInt
(3.toRomanNumeral * C / V) - L - X // res7: RomanNumeral = nulla
import nl.gn0s1s.julius.RomanNumeral.RomanNumeralFromString
"XX".toRomanNumeral.get * V // res8: RomanNumeral = C
```
## Links
Roman Numerals:
- General information - https://en.wikipedia.org/wiki/Roman_numerals
- Algorithms - http://turner.faculty.swau.edu/mathematics/materialslibrary/roman/
- Algorithms - http://scienceblogs.com/goodmath/2006/08/16/roman-numerals-and-arithmetic/
Scala related references:
- ScalaCheck - https://scalacheck.org/
- Sealed traits - http://underscore.io/blog/posts/2015/06/02/everything-about-sealed.html
## License
The code is available under the [Mozilla Public License, version 2.0](LICENSE).