Better (load) call error checking

kiss/src/kiss/Kiss.hx

@@ -97,7 +97,10 @@ class Kiss {
                 #end
                 switch (nextExp.def) {
                     // (load... ) is the specialest of forms because it calls build() again and those fields need to be merged
-                    case CallExp({pos: _, def: Symbol("load")}, [{pos: _, def: StrExp(otherKissFile)}]):
+                    case CallExp({pos: _, def: Symbol("load")}, loadArgs):
+                        nextExp.checkNumArgs(1, 1, "(load \"[file]\")");
+                        switch (loadArgs[0].def) {
+                            case StrExp(otherKissFile):
                                 var filePath = Path.join([loadingDirectory, otherKissFile]);
                                 if (!k.loadedFiles.exists(filePath)) {
                                     var loadedFields = Kiss.build(filePath, k, false);
@@ -106,6 +109,9 @@ class Kiss {
                                     }
                                     k.loadedFiles[filePath] = true;
                                 }
+                            default:
+                                throw CompileError.fromExp(loadArgs[0], "only argument to load should be a string literal");
+                        }
                     default:
                         var field = readerExpToField(nextExp, k);
                         if (field != null) {