Kotlin Arithmetic Parser
Karith
Kotlin Arithmetic Parser
Docs (WIP) | KDoc
NOTE: This is a work in progress and the API might still change significantly. Make sure to check the changelog before upgrading versions.
Installation
Gradle (Groovy)
implementation 'dev.franckyi:karith:0.1.0'
Gradle (Kotlin)
implementation("dev.franckyi:karith:0.1.0")
Maven
<dependency>
<groupId>dev.franckyi</groupId>
<artifactId>karith</artifactId>
<version>0.1.0</version>
</dependency>
Usage
The Karith library is designed to be easy to use and highly configurable.
Simple example
val res = "1 + 2".result() // 3.0
val res = "3a + b".resultWith("a" to 1, "b" to 2) // 5.0
val res = "6 % 4".intResult() // 2
val res = "6 / min(x,y)".intResultWith("x" to 2, "y" to 3) // 3
Note: The above example uses a global context. It is recommended to build and use your own context instead.
Creating a context
First of all, you need to create a context. A context is an object that contains all the operators, variables and functions that you can parse in an expression. A context can also cache expressions and their result.
A context is usually created by including some modules, operators, variables and functions in it. Modules are collections of operators, variables and functions. You can find more information about builtin modules, operators, variables and functions in the Builtin elements section.
You can easily create your own context using helper functions. Here is an example:
// creates a context with + and - operators only
val ctx = context { withOperators(Operators.PLUS, Operators.MINUS) }
// creates a context with basic operators (+, -, *, / and %)
val ctx = baseContext()
// creates a context with basic operators and functions
val ctx = defaultContext()
Parsing an expression
You can parse an expression using the expression or expressionWith method of a context.
val expr = ctx.expression("1 + 2")
val expr = ctx.expressionWith("3a + b", "a", "b")
val expr = ctx.expression("6 % 4")
val expr = ctx.expressionWith("6 / min(x,y)", "x", "y")
Computing a result
You can compute the result of an expression using the result, intResult resultWith, or intResultWith method of
an expression.
val expr = ctx.expression("1 + 2")
val res = expr.result() // 3.0
val expr = ctx.expressionWith("3a + b", "a", "b")
val res = expr.resultWith("a" to 1, "b" to 2) // 5.0
val expr = ctx.expression("6 % 4")
val res = expr.intResult() // 2
val expr = ctx.expressionWith("6 / min(x,y)", "x", "y")
val res = expr.intResultWith("x" to 2, "y" to 3) // 3
Advanced usage
TODO
Builtin elements
Cache
Internal algorithm
Building
You can build Karith using these commands:
git clone https://github.com/Franckyi/Karith
cd Karith
./gradlew build