jank is Clojure on top of C++. It has C++ interop unlike any other language. Templates, virtual functions, exceptions, overload resolution, and RAII all just work in jank. No boilerplate necessary. Just include your headers and go!
jank is a robust Clojure dialect. It offers interactive REPL-driven development powered by a Clang-based C++ JIT compiler.
(ns my.app.filesystem
(:include "boost/filesystem.hpp")
(:refer-global :rename {boost.filesystem.file_size file-size}))
(defn file-info [file-path]
(try
(let [bytes (file-size (cpp/cast std.string file-path))]
{:path file-path
:size bytes})
(catch boost.filesystem.filesystem_error e
{:path file-path
:error (.what e)})))
(file-info "/etc/passwd")
; {:path "/etc/passwd", :size 4025}
(file-info "/root/.bash_history")
; {:path "/root/.bash_history"
; :error "boost::filesystem::file_size: Permission denied [system:13]: \"/root/.bash_history\""}
jank is a full-on Clojure dialect, with C++ interop instead of Java interop. There's a :jank
reader conditional for when you need it.
jank can include any C++ source, link to any C or C++ library, and it uses the C++ type system. jank even compiles to C++!
jank uses Leiningen-based project management and has a rich native build system. It's easy to add C and C++ dependencies to your project.
Use your favorite nREPL editor plugin. jank contains an LLVM-based JIT runtime to compile C++ code on the fly.
jank's native build system can find your installed native dependencies or build them from source. Adding a new dependency is a one line change.
(defproject imgui+glfw "0.1-SNAPSHOT"
:dependencies [[org.jank-lang.commons/imgui-glfw-sys "2026.06-6"]
[org.jank-lang.commons/imgui-opengl2-sys "2026.06-6"]
[org.jank-lang.commons/gl-sys "2026.06-1"]]
:plugins [[org.jank-lang/lein-jank "2026.06-2"]]
:middleware [leiningen.jank/middleware]
:main imgui+glfw.main
:profiles {:base {:jank {:target-dir "target/debug"
:optimization-level 0}}
:release {:jank {:target-dir "target/release"
:optimization-level 3}}})
jank brings functional, immutable data and REPL-driven development to your game development workflow. With jank, you can reach into C++ whenever you want the extra performance. No bridges, no function/type registration, no marshalling, no callbacks.
(ns imgui+glfw.main
(:include "GLFW/glfw3.h"
"imgui.h" "imgui_impl_glfw.h" "imgui_impl_opengl2.h"))
(defn -main []
(cpp/glfwInit)
(let [window* (cpp/glfwCreateWindow 400 300
"jank"
cpp/nullptr cpp/nullptr)]
(cpp/glfwMakeContextCurrent window*)
(cpp/ImGui.CreateContext)
(cpp/ImGui_ImplGlfw_InitForOpenGL window* true)
(cpp/ImGui_ImplOpenGL2_Init)
(while (cpp/! (cpp/glfwWindowShouldClose window*))
(cpp/glfwPollEvents)
(cpp/ImGui_ImplOpenGL2_NewFrame)
(cpp/ImGui_ImplGlfw_NewFrame)
(cpp/ImGui.NewFrame)
(when (cpp/ImGui.Begin "jank")
(cpp/ImGui.Text "Hello, jank and imgui!"))
(cpp/ImGui.End)
(cpp/ImGui.Render)
(cpp/ImGui_ImplOpenGL2_RenderDrawData (cpp/ImGui.GetDrawData))
(cpp/glfwSwapBuffers window*))
(cpp/glfwTerminate)))