diff --git a/.dotter/global.toml b/.dotter/global.toml
index 69d2ab9..f85bfe2 100644
--- a/.dotter/global.toml
+++ b/.dotter/global.toml
@@ -4,6 +4,7 @@
 default_target_type = "symbolic"
 
 [helpers]
+with_default = ".dotter/helpers/var_with_default.rhai"
 
 # BASE: A base system. Sets up a nice xdg (zsh) shell environment, utility scripts and
 #       a development environment based on git and nvim.
diff --git a/.dotter/helpers/var_with_default.rhai b/.dotter/helpers/var_with_default.rhai
new file mode 100644
index 0000000..1d4858b
--- /dev/null
+++ b/.dotter/helpers/var_with_default.rhai
@@ -0,0 +1,12 @@
+// tests the type of variable passed in
+// if 'no' type (does not exist or cant be parsed)
+// we return the second, 'default' variable
+
+fn choose(a, b) {
+    if type_of(a) != "()" {
+        return a;
+    }
+    return b;
+}
+
+choose(params[0], params[1])