add piston nix pkg for julia

runtimes/default.nix

@@ -38,4 +38,5 @@ args: {
     "lolcode" = import ./lolcode.nix args;
     "sbcl-lisp" = import ./sbcl-lisp.nix args;
     "jvm-kotlin" = import ./jvm-kotlin.nix args;
+    "julia" = import ./julia.nix args;
 }

runtimes/julia.nix

@@ -0,0 +1,29 @@
+{pkgs, piston, ...}:
+let
+    pkg = pkgs.julia-bin;
+in piston.mkRuntime {
+    language = "julia";
+    version = pkg.version;
+
+    aliases = [
+        "jl"
+    ];
+    
+    run = ''
+        ${pkg}/bin/julia --startup-file=no --history-file=no "$@"
+    '';
+
+    tests = [
+        (piston.mkTest {
+            files = {
+                "test.jl" = ''
+                    println("OK")
+                '';
+            };
+            args = [];
+            stdin = "";
+            packages = [];
+            main = "test.jl";
+        })
+    ];
+}