add clause for join with empty list and separator

build/out.mjs

@@ -6489,7 +6489,7 @@ var __emscripten_stack_alloc = (a0) => (__emscripten_stack_alloc = wasmExports['
 var _emscripten_stack_get_current = () => (_emscripten_stack_get_current = wasmExports['emscripten_stack_get_current'])();
 var ___cxa_is_pointer_type = createExportWrapper('__cxa_is_pointer_type', 1);
 var dynCall_jiji = Module['dynCall_jiji'] = createExportWrapper('dynCall_jiji', 5);
-var ___emscripten_embedded_file_data = Module['___emscripten_embedded_file_data'] = 1836260;
+var ___emscripten_embedded_file_data = Module['___emscripten_embedded_file_data'] = 1837508;
 function invoke_i(index) {
   var sp = stackSave();
   try {

package-lock.json

@@ -1,12 +1,12 @@
 {
   "name": "@ludus/ludus-js-pure",
-  "version": "0.1.23",
+  "version": "0.1.24",
   "lockfileVersion": 3,
   "requires": true,
   "packages": {
     "": {
       "name": "@ludus/ludus-js-pure",
-      "version": "0.1.23",
+      "version": "0.1.24",
       "license": "GPL-3.0",
       "devDependencies": {
         "shadow-cljs": "^2.26.0",

package.json

@@ -1,6 +1,6 @@
 {
   "name": "@ludus/ludus-js-pure",
-  "version": "0.1.23",
+  "version": "0.1.24",
   "description": "A Ludus interpreter in a pure JS function.",
   "type": "module",
   "main": "build/ludus.mjs",

prelude.ld

@@ -326,6 +326,7 @@ fn join {
 	([]) -> ""
 	([str as :string]) -> str
 	(strs as :list) -> join (strs, "")
+	([], separator as :string) -> ""
 	([str as :string], separator as :string) -> str
 	([str, ...strs], separator as :string) -> fold (
 		fn (joined, to_join) -> concat (joined, separator, to_join)

src/interpreter.janet

@@ -463,7 +463,8 @@
     [:dict :keyword] (get prev curr :^nil)
     [:nil :keyword] :^nil
     [:pkg :keyword] (get prev curr :^nil)
-    [:pkg :pkg-kw] (get prev curr :^nil)))
+    [:pkg :pkg-kw] (get prev curr :^nil)
+    (error (string "cannot call " (b/ludus/type prev) " `" (b/show prev) "`"))))
 
 (defn- synthetic [ast ctx]
   (def terms (ast :data))