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Functional companion to Kotlin’s Compiler & IDE

Λrrow Meta is a meta-programming library designed to build compiler plugins for Kotlin.

Built with Meta


Λrrow Analysis extends the capabilities of the Kotlin compiler with compile-time checked pre and post-conditions for functions, and invariants for types and mutable variables. This allows Λrrow Analysis to detect many common types of mistakes (like out-of-bounds indexing), which you can extend with additional checks for your particular domain.

Get started with Λrrow Analysis

Previously built with Meta

These plug-ins are no longer developed as part of the Λrrow Meta organization.


Λrrow Optics provide a nice DSL to query and transform immutable values. A compiler plug-in to provide automatic generation of the necessary boilerplate was previously built with Meta, but it has been replaced by KSP.


Λrrow Proofs provides a way to declare contextual values, which are resolved at compile-time by the plug-in. Dependency Injection without the hassle! Λrrow Proofs is no longer in development.

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