mirror of
https://github.com/vercel-labs/scriptc.git
synced 2026-10-22 05:59:31 +08:00
Chris Tate
483dc07234
- Parse standalone source with an isolated native TypeScript session and preserve AST ownership across edits. - Move package declaration projection and import scanning onto statically compilable syntax passes. - Support forwarded visitor results and guarded native iteration while preserving JSDoc annotations.
59 lines
2.5 KiB
TypeScript
59 lines
2.5 KiB
TypeScript
// Generic visitor result types can be void, undefined, or real values.
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// Every callback still runs exactly once; only truthy results stop a walk.
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class Visitor {
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each<T>(visit: (value: number) => T, visitList?: (values: number[]) => T): T | undefined {
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const values = [0, 1, 2];
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if (visitList !== undefined) {
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const result = visitList(values);
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if (result) return result;
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}
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for (const value of values) {
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const result = visit(value);
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if (result) return result;
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}
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return undefined;
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}
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store<T = void>(visit: () => T): string {
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let result: T;
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result = visit();
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return typeof result;
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}
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}
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function once<T>(visit: () => T): T | undefined {
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const value = visit();
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return value;
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}
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const visitor = new Visitor();
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let total = 0;
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visitor.each((value) => { total += value; console.log("void", value); });
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console.log("total", total);
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visitor.each<void>((value) => { console.log("explicit", value); });
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visitor.each((value) => { console.log("undefined", value); return undefined; });
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visitor.each((value) => { console.log("element", value); }, (values) => { console.log("list", values.length); });
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console.log("number", visitor.each((value) => value));
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console.log("boolean", visitor.each((value) => value === 2));
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console.log("string", visitor.each((value) => value === 2 ? "found" : ""));
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console.log("list result", visitor.each((value) => value, (values) => values.length));
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console.log("store", visitor.store(() => { console.log("stored void"); }));
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console.log("explicit store", visitor.store<void>(() => { console.log("stored explicit"); }));
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console.log("value store", visitor.store(() => 42));
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once(() => { console.log("once void"); });
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console.log("once value", once(() => 42));
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// A generic wrapper forwards the symbolic return type to a generic method.
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function forwarded<T>(visit: (value: number) => T | undefined): T | undefined {
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return visitor.each(visit);
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}
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function forwardedAgain<T>(visit: (value: number) => T | undefined): T | undefined {
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return forwarded(visit);
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}
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forwarded((value) => { console.log("forward visit", value); });
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forwardedAgain((value) => { console.log("forward again visit", value); });
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console.log("forwarded bool", forwarded((value) => value === 2 ? true : undefined));
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console.log("forwarded false", forwardedAgain((value) => value === 2 ? false : undefined));
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console.log("forwarded number", forwardedAgain((value) => value === 2 ? 17 : undefined));
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console.log("forwarded string", forwardedAgain((value) => value === 2 ? "found" : undefined));
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