feat: 🎸 introduce FnValue

Author: streamich

src/value/FnValue.ts

@@ -0,0 +1,15 @@
+import {Value} from './Value';
+import type {Printable} from 'tree-dump/lib/types';
+import type * as classes from '../type';
+
+export class FnValue<T extends classes.FnType<any, any, any>> extends Value<T> implements Printable {
+  public async exec(input: classes.ResolveType<T['req']>, ctx?: unknown): Promise<Value<T['res']>> {
+    const fn = this.data as any;
+    const output = await fn(input, ctx);
+    return new Value(output, this.type!.res);
+  }
+
+  public name(): string {
+    return 'FnValue';
+  }
+}