Still WIP

js/entity/AlternativesEntity.js

@@ -0,0 +1,29 @@
+import P from "parsernostrum"
+import Grammar from "../serialization/Grammar.js"
+import IEntity from "./IEntity.js"
+
+export default class AlternativesEntity extends IEntity {
+
+    /** @type {(typeof IEntity)[]} */
+    static alternatives = []
+
+    static createGrammar() {
+        return this.alternatives
+            .map(entity => entity.grammar)
+            .reduce((acc, cur) => !cur || cur === Grammar.unknownValue || acc === Grammar.unknownValue
+                ? Grammar.unknownValue
+                : P.alt(acc, cur)
+            )
+    }
+
+    /**
+     * @template {(typeof IEntity)[]} Types
+     * @param {Types} types
+     */
+    static accepting(...types) {
+        const result = /** @type {typeof AlternativesEntity & { alternatives: Types }} */(this.asUniqueClass())
+        result.alternatives = types
+        result.grammar = result.createGrammar()
+        return result
+    }
+}