mirror of
https://github.com/vercel-labs/scriptc.git
synced 2026-10-24 06:14:01 +08:00
Chris Tate
6aa48c111a
- Support concrete generic inheritance, forward references, and nullable substitutions. - Bound recursive specialization demands while preserving independent concrete uses. - Preserve class identity through checked assertions and contextual lowering.
29 lines
1.4 KiB
TypeScript
29 lines
1.4 KiB
TypeScript
class Entry { value: number; constructor(value: number) { this.value = value; } }
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class Cache<K, V> {
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entries = new Map<K, V>();
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get(key: K, fallback: V): V { return this.entries.get(key) ?? fallback; }
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read(key: K): V | undefined { return this.entries.get(key); }
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}
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function lookup<V>(cache: Cache<string, V>, key: string, fallback: V): V {
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return cache.get(key, fallback);
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}
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const objects = new Cache<string, Entry | undefined>();
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const entry = new Entry(7);
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objects.entries.set("present", entry);
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objects.entries.set("empty", undefined);
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console.log(lookup(objects, "present", undefined) === entry);
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console.log(objects.read("missing"), lookup(objects, "empty", entry) === entry);
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const scalars = new Cache<string, number | null | undefined>();
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scalars.entries.set("zero", 0);
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scalars.entries.set("null", null);
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console.log(scalars.get("zero", 9), scalars.get("null", 9), scalars.get("missing", undefined));
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type Variant = { kind: "value"; value: number } | { kind: "text"; text: string };
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const variants = new Cache<string, Variant | undefined>();
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variants.entries.set("a", { kind: "value", value: 3 });
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variants.entries.set("b", { kind: "text", text: "ok" });
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function format(value: Variant | undefined): string {
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if (value === undefined) return "missing";
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return value.kind === "value" ? String(value.value) : value.text;
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}
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console.log(format(variants.read("a")), format(variants.read("b")), format(variants.read("c")));
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