init

lib/rule.ts

@@ -0,0 +1,34 @@
+import { StructOfArr } from "./types.ts";
+import { zip } from "./utils.ts";
+
+export class Rule<V extends string[]> {
+    private separators: ({ kind: "word", word: string } | { kind: "end" })[];
+    private vars: V;
+
+    public constructor(separators: string[], vars: V) {
+        this.separators = separators.map(word => ({ kind: "word", word }));
+        this.vars = vars;
+        this.separators.push({ kind: "end" });
+    }
+
+    public get(text: string): StructOfArr<V, string> | null {
+        const first_sep = this.separators[0] ?? "";
+        if (first_sep.kind === "end") {
+            if (text.length > 0) return null;
+            else return {} as StructOfArr<V, string>;
+        }
+        if (!text.includes(first_sep.word)) return null;
+        let [val, rest] = text.split(first_sep.word, 2);
+        const result = {} as Record<string, string>;
+        for (const [key, sep] of zip(this.vars, this.separators.slice(1))) {
+            if (sep.kind === "end") {
+                result[key] = rest;
+                break;
+            }
+            if (!rest.includes(sep.word)) return null;
+            [val, rest] = rest.split(sep.word, 2);
+            result[key] = val;
+        }
+        return result as StructOfArr<V, string>;
+    }
+}