🚀 What's new in Kotools Types 5.2.0

[LVMVRQUXL]

Kotools Types 5.2.0 is out, and it's the biggest release yet for org.kotools.types.number. Four changes stand out. Each gets its own dedicated, deep-dive article — this post is the short tour.

🧮 Integer got a faster internal representation

Before 5.2.0, Integer stored its value as a String and reparsed it on every arithmetic operation. That representation is gone: Integer now delegates to java.lang.BigInteger on Kotlin/JVM, BigInt on Kotlin/JS, and a custom arbitrary-precision implementation on Kotlin/Native — with no parsing involved in +, -, *, div, or rem. This was one of the most frequently requested changes from the community.

🎯 Decimal arrives: exact arithmetic without floating-point

0.1 + 0.2 != 0.3 is a classic trap with Double/Float, because binary floating-point can't exactly represent most base-10 decimals. Decimal, a brand-new type in org.kotools.types.number, sidesteps the problem entirely by never using floating-point in the first place — addition, subtraction, and multiplication are always exact.

➗ Integer division is now Euclidean, and total

Integer.div and Integer.rem now always satisfy 0 <= remainder < |divisor| — no more negative remainders depending on the sign of the operands. The divisor is also now a NonZeroInteger, a type that rules out division by zero at compile time, so these operations can no longer throw or return null because of a zero divisor.

🔒 Sign as a type: NonZeroInteger, NonNegativeInteger, NonPositiveInteger

Three new types turn "this integer can never be negative" (or positive, or zero) from a runtime check into a compile-time guarantee, with arithmetic operators that preserve those guarantees across additions and multiplications.

🛠️ Adding Kotools Types to your project

See the Installation section of the project's README for Gradle/Maven setup — this article was written against version 5.2.0.

This API is @ExperimentalKotoolsTypesApi, so opt in either per call-site with @OptIn(ExperimentalKotoolsTypesApi::class) or project-wide via the compiler argument:

// build.gradle.kts
kotlin {
    compilerOptions {
        freeCompilerArgs.add("-opt-in=org.kotools.types.ExperimentalKotoolsTypesApi")
    }
}

See also: GitHub, API reference

💬 Discussion

Which of these four changes affects your code the most?