add piston nix pkg for yabasic (replaces freebasic)

runtimes/yabasic.nix

@@ -0,0 +1,29 @@
+{pkgs, piston, ...}:
+let
+    pkg = pkgs.yabasic;
+in piston.mkRuntime {
+    language = "yabasic";
+    version = pkg.version;
+
+    aliases = [
+        "basic"
+    ];
+
+    run = ''
+        ${pkg}/bin/yabasic "$@"
+    '';
+
+    tests = [
+        (piston.mkTest {
+            files = {
+                "test.bas" = ''
+                    PRINT "OK"
+                '';
+            };
+            args = [];
+            stdin = "";
+            packages = [];
+            main = "test.bas";
+        })
+    ];
+}