Expression Evaluator

Library written in Kotlin to help evaluate mathematical expressions that can be extended by custom operators and functions.

Setup

Add the JitPack repository to your build file

allprojects {
  repositories {
    ...
    maven { url 'https://jitpack.io' }
  }
}

Add library dependency to your project build file

dependencies {
  implementation 'com.github.cregus:expression-evaluator:1.0.2'
}

Sample usage

Simple expressions.

println(evaluate("2+2")) // Prints 4

Using functions.

println(evaluate("round(10/3,2)")) // Prints 3.33

Using variables.

println(evaluate("x*y", data = mapOf("x" to 2, "y" to 3))) // Prints 6

Defining custom functions.

Tokenizer.registerFunction("random") { a, b -> Random.nextInt(a.toInt(), b.toInt()).toBigDecimal() }
println(evaluate("random(1,6)")) // Prints random number between 1 (inclusive) and 6 (exclusive)