perf(ts): return a Result of an Option of a number in a slot

quest/m3/README.md

@@ -35,7 +35,6 @@ generic std gap is planned here even when moq never calls it.
 - [A reversed zip's per-pair cost](/quest/m3/ts-zip-rev-overhead.md) - a reversed by-index zip costs per pair what a forward one does, or the gap is explained
 - [Whole writes into a lazy cell or thread-local key](/quest/m3/ts-lazy-writes.md) - a whole write through a `&mut` to a `LazyCell`, `LazyLock`, or `LocalKey` keeps its state
 - [Type errors at the Rust that made them](/quest/m3/ts-span-precision.md) - a `tsc` error on output names the tail expression or call argument that made it
-- [An Option of numbers in the result slot](/quest/m3/ts-option-slot.md) - `varint_opt`'s `Option` comes back through the slot with no object per call
 - [Fresh writes through a zip, a copy, and a repeat](/quest/m3/ts-fresh-shapes.md) - zipping a `Vec<[T; N]>`, reading a `T` out of `Zip::next`, and `copied` or `vec![x; n]` over a `Copy` type translate
 - [Python's wake on the loop's own thread](/quest/m3/ffi-python-wake.md) - a wake on the event loop's thread resumes the future with no socket pair
 - [Python's call cost](/quest/m3/ffi-python-calls.md) - a call on an object costs what BoltFFI's does, or the gap is explained

ts/MIGRATE.md

@@ -49,8 +49,9 @@
   whose object its body never makes as its `data`, `start`, and `length`:
   `read(buf, form)` is `read(buf.data, buf.start, buf.length, form)`. A caller takes
   which from the output. One that returns a `Result` of byte slices
-  and scalars, or of numbers alone, returns its error or `undefined`, and leaves the `Ok`'s parts in a
-  slot `lib.ts` exports, named for the payload type, such as `out$ref_slice_u8`. If the
+  and scalars, or of numbers alone, an `Option` of one counting as a number, such as
+  `Result<Option<u64>, E>`, returns its error or `undefined`, and leaves the `Ok`'s parts in a
+  slot `lib.ts` exports, named for the payload type, such as `out$ref_slice_u8` or `out$Option_u64`. If the
   `Ok`'s first part is a number, it returns that, or `undefined` for an error, and leaves
   the rest, or the error as `err`, in the slot, such as `out$tuple2_u64_ref_slice_u8`. A root still takes an `rt.ByteSlice` and returns
   the `Result`.

ts/README.md

@@ -803,7 +803,8 @@ they need.
   the geometric mean, and frame decode at 0.61, 0.56, 0.70, and 0.61, with the A/A route
   within 0.04 and encode no slower. A tuple or `Result` of numbers alone is held so only
   where it meets a slot below, and its object, such as an `rt.Ok`, counts as made at each
-  read that makes it. A return is still a `ByteSlice` but for the `Result`s below.
+  read that makes it. An `Option` of a number is one part, that or `undefined`, as its JS
+  value is. A return is still a `ByteSlice` but for the `Result`s below.
 - A function only translated code calls takes each `&[u8]` or `&[u8; N]` parameter as
   three, its `data`, `start`, and `length`, which its body holds as that local's parts:
   not a root, which the outside calls, a closure, or an `async fn`. One whose object the
@@ -819,8 +820,8 @@ they need.
   1.01-1.05 over two runs, with the A/A route within 0.05, Firefox and Bun within their
   noise, and Node's varint decode at 1.11-1.15.
 - A function of the crate's that only translated code calls and that returns a `Result`
-  of byte slices and scalars, or of numbers alone, such as `Result<(u64, &[u8]), E>` or
-  `Result<u64, E>`, whose error is one JS
+  of byte slices and scalars, or of numbers alone, such as `Result<(u64, &[u8]), E>`,
+  `Result<u64, E>`, or `Result<Option<u64>, E>`, whose error is one JS
   value that is never `undefined`, writes the `Ok`'s parts into a module-level slot and returns the error or
   `undefined`. The slot is shared by every function returning that payload type, in
   `lib.ts` and named for the type as the shims are, as `out$ref_slice_u8` or `out$u64`, so

ts/fixtures/codec/expected/coding/decode.Decoder.ts

@@ -1,7 +1,7 @@
 // Generated by rust2-ts. Do not edit.
 
 import * as rt from "../rt.ts";
-import { out$bool, out$ref_slice_u8, out$tuple2_u64_ref_slice_u8, out$u16, out$u64, out$u8 } from "../lib.ts";
+import { out$Option_u64, out$bool, out$ref_slice_u8, out$tuple2_u64_ref_slice_u8, out$u16, out$u64, out$u8 } from "../lib.ts";
 import * as DecodeError from "../coding/decode.DecodeError.ts";
 import { read } from "../coding/varint.ts";
 import type * as Form from "../coding/varint.Form.ts";
@@ -190,13 +190,14 @@ export function varint(self: Decoder): rt.u64 | undefined {
 }
 
 /** Read an optional varint: 0 is `None`, and `n + 1` is `Some(n)`. */
-export function varintOpt(self: Decoder): rt.Result<rt.u64 | undefined, DecodeError.DecodeError> {
+export function varintOpt(self: Decoder): DecodeError.DecodeError | undefined {
 	const part: rt.u64 | undefined = varint(self);
 	const err: DecodeError.DecodeError | undefined = part === undefined ? out$u64.err as DecodeError.DecodeError : undefined;
 	if (err === undefined) {
-		return rt.Ok(rt.u64CheckedSub(part as rt.u64, 1));
+		out$Option_u64.p = rt.u64CheckedSub(part as rt.u64, 1);
+		return undefined;
 	}
-	return rt.Err(err as DecodeError.DecodeError);
+	return err as DecodeError.DecodeError;
 }
 
 /** Read a varint length, then that many raw bytes. */

ts/fixtures/codec/expected/harness.ts

@@ -1,7 +1,7 @@
 // Generated by rust2-ts. Do not edit.
 
 import * as rt from "./rt.ts";
-import { out$bool, out$ref_slice_u8, out$u16, out$u64, out$u8, out$usize } from "./lib.ts";
+import { out$Option_u64, out$bool, out$ref_slice_u8, out$u16, out$u64, out$u8, out$usize } from "./lib.ts";
 import * as DecodeError from "./coding/decode.DecodeError.ts";
 import * as Decoder from "./coding/decode.Decoder.ts";
 import * as EncodeError from "./coding/encode.EncodeError.ts";
@@ -224,41 +224,42 @@ export function decodeScript(dataData: Uint8Array, dataStart: number, dataLen: n
 export function decodeStep(r: Decoder.Decoder, step: rt.u8, out: rt.ByteVec): rt.Result<undefined, DecodeError.DecodeError> {
 	const _5: rt.u8 = rt.u8Rem(step, 10);
 	if (_5 === 0) {
-		const part11: rt.u8 | undefined = Decoder.u8(r);
-		const err7: DecodeError.DecodeError | undefined = part11 === undefined ? out$u8.err as DecodeError.DecodeError : undefined;
+		const part12: rt.u8 | undefined = Decoder.u8(r);
+		const err8: DecodeError.DecodeError | undefined = part12 === undefined ? out$u8.err as DecodeError.DecodeError : undefined;
+		if (err8 === undefined) {
+			rt.byteVecPush(out, part12 as rt.u8);
+		} else {
+			return rt.Err(err8 as DecodeError.DecodeError);
+		}
+	} else if (_5 === 1) {
+		const part11: rt.u16 | undefined = Decoder.u16(r);
+		const err7: DecodeError.DecodeError | undefined = part11 === undefined ? out$u16.err as DecodeError.DecodeError : undefined;
 		if (err7 === undefined) {
-			rt.byteVecPush(out, part11 as rt.u8);
+			rt.byteVecExtendFromSlice(out, rt.byteSliceFrom(rt.u16ToBeBytes(part11 as rt.u16)));
 		} else {
 			return rt.Err(err7 as DecodeError.DecodeError);
 		}
-	} else if (_5 === 1) {
-		const part10: rt.u16 | undefined = Decoder.u16(r);
-		const err6: DecodeError.DecodeError | undefined = part10 === undefined ? out$u16.err as DecodeError.DecodeError : undefined;
+	} else if (_5 === 2) {
+		const err6: DecodeError.DecodeError | undefined = Decoder.bool(r);
+		const part10: boolean = out$bool.p;
 		if (err6 === undefined) {
-			rt.byteVecExtendFromSlice(out, rt.byteSliceFrom(rt.u16ToBeBytes(part10 as rt.u16)));
+			rt.byteVecPush(out, part10 ? 1 : 0);
 		} else {
 			return rt.Err(err6 as DecodeError.DecodeError);
 		}
-	} else if (_5 === 2) {
-		const err5: DecodeError.DecodeError | undefined = Decoder.bool(r);
-		const part9: boolean = out$bool.p;
+	} else if (_5 === 3) {
+		const part9: rt.u64 | undefined = Decoder.varint(r);
+		const err5: DecodeError.DecodeError | undefined = part9 === undefined ? out$u64.err as DecodeError.DecodeError : undefined;
 		if (err5 === undefined) {
-			rt.byteVecPush(out, part9 ? 1 : 0);
+			putU64(out, part9 as rt.u64);
 		} else {
 			return rt.Err(err5 as DecodeError.DecodeError);
 		}
-	} else if (_5 === 3) {
-		const part8: rt.u64 | undefined = Decoder.varint(r);
-		const err4: DecodeError.DecodeError | undefined = part8 === undefined ? out$u64.err as DecodeError.DecodeError : undefined;
-		if (err4 === undefined) {
-			putU64(out, part8 as rt.u64);
-		} else {
-			return rt.Err(err4 as DecodeError.DecodeError);
-		}
 	} else if (_5 === 4) {
-		const _31: rt.Result<rt.u64 | undefined, DecodeError.DecodeError> = Decoder.varintOpt(r);
-		if (_31.ok) {
-			const val5: rt.u64 | undefined = _31.value;
+		const err4: DecodeError.DecodeError | undefined = Decoder.varintOpt(r);
+		const part8: rt.u64 | undefined = out$Option_u64.p;
+		if (err4 === undefined) {
+			const val5: rt.u64 | undefined = part8;
 			if (val5 === undefined) {
 				rt.byteVecPush(out, 0);
 			} else {
@@ -267,7 +268,7 @@ export function decodeStep(r: Decoder.Decoder, step: rt.u8, out: rt.ByteVec): rt
 				putU64(out, v);
 			}
 		} else {
-			return _31;
+			return rt.Err(err4 as DecodeError.DecodeError);
 		}
 	} else if (_5 === 5) {
 		const err3: DecodeError.DecodeError | undefined = Decoder.bytes(r);

ts/fixtures/codec/expected/lib.ts

@@ -7,6 +7,8 @@ export function copy$bench_Timestamp(v: Timestamp.Timestamp): Timestamp.Timestam
 	return { value: v.value, scale: v.scale };
 }
 
+export const out$Option_u64: { p: rt.u64 | undefined } = { p: undefined as never };
+
 export const out$bool: { p: boolean } = { p: undefined as never };
 
 export const out$ref_slice_u8: { pData: Uint8Array; pStart: number; pLen: number } = { pData: undefined as never, pStart: undefined as never, pLen: undefined as never };

ts/fixtures/lang/cells/expected/cells.ts

@@ -1,7 +1,7 @@
 // Generated by rust2-ts. Do not edit.
 
 import * as rt from "./rt.ts";
-import { out$u64, out$u8 } from "./lib.ts";
+import { out$Option_u8, out$u64, out$u8 } from "./lib.ts";
 import { thenSome$0d5am30 } from "./core/bool.ts";
 import { unwrapOr$0r2bmpr as option_unwrapOr$0r2bmpr } from "./core/option.ts";
 import { err$1nbmqmx, map$1ma2nl9 as result_map$1ma2nl9, map$0l5uclx as result_map$0l5uclx, map$14n87rz as result_map$14n87rz, map$0h1vl84 as result_map$0h1vl84, map$03hz3l7 as result_map$03hz3l7, map$0yqi183 as result_map$0yqi183 } from "./core/result.ts";
@@ -153,20 +153,24 @@ export function cellOption(dataData: Uint8Array, dataStart: number, dataLen: num
 			const _166: rt.u8 = rt.u8Rem(v2, 4);
 			if (_166 === 0 || _166 === 1) {
 				result = rt.onceGetOrTryInit(cell, (): rt.Result<rt.u8 | undefined, rt.u8> => {
-					return made$Option_u8(make, v2);
+					const err4 = made$Option_u8(make, v2);
+					return err4 !== undefined ? rt.Err(err4 as rt.u8) : rt.Ok(out$Option_u8.p);
 				}, undefined, rt.None);
 			} else if (_166 === 2) {
 				const _174: rt.OnceCell<rt.u8 | undefined, rt.None> = cell;
 				result = rt.onceGetOrTryInit(cell, (): rt.Result<rt.u8 | undefined, rt.u8> => {
 					rt.onceSet(_174, make(v2 ^ 1), rt.None);
-					return made$Option_u8(make, v2);
+					const err3 = made$Option_u8(make, v2);
+					return err3 !== undefined ? rt.Err(err3 as rt.u8) : rt.Ok(out$Option_u8.p);
 				}, undefined, rt.None);
 			} else {
 				const _179: rt.OnceCell<rt.u8 | undefined, rt.None> = cell;
 				result = rt.onceGetOrTryInit(cell, (): rt.Result<rt.u8 | undefined, rt.u8> => {
-					return made$Option_u8(make, option_unwrapOr$0r2bmpr(err$1nbmqmx(result_map$1ma2nl9(rt.onceGetOrTryInit(_179, (): rt.Result<rt.u8 | undefined, rt.u8> => {
-						return made$Option_u8(make, v2 ^ 1);
+					const err2 = made$Option_u8(make, option_unwrapOr$0r2bmpr(err$1nbmqmx(result_map$1ma2nl9(rt.onceGetOrTryInit(_179, (): rt.Result<rt.u8 | undefined, rt.u8> => {
+						const err = made$Option_u8(make, v2 ^ 1);
+						return err !== undefined ? rt.Err(err as rt.u8) : rt.Ok(out$Option_u8.p);
 					}, undefined, rt.None), (_22: rt.u8 | undefined): undefined => {})), v2));
+					return err2 !== undefined ? rt.Err(err2 as rt.u8) : rt.Ok(out$Option_u8.p);
 				}, undefined, rt.None);
 			}
 			if (result.ok) {
@@ -1289,20 +1293,24 @@ export function lockOption(dataData: Uint8Array, dataStart: number, dataLen: num
 			const _166: rt.u8 = rt.u8Rem(v2, 4);
 			if (_166 === 0 || _166 === 1) {
 				result = rt.onceGetOrTryInit(cell, (): rt.Result<rt.u8 | undefined, rt.u8> => {
-					return made$Option_u8(make, v2);
+					const err4 = made$Option_u8(make, v2);
+					return err4 !== undefined ? rt.Err(err4 as rt.u8) : rt.Ok(out$Option_u8.p);
 				}, undefined, rt.None);
 			} else if (_166 === 2) {
 				const _174: rt.OnceLock<rt.u8 | undefined, rt.None> = cell;
 				result = rt.onceGetOrTryInit(cell, (): rt.Result<rt.u8 | undefined, rt.u8> => {
 					rt.onceSet(_174, make(v2 ^ 1), rt.None);
-					return made$Option_u8(make, v2);
+					const err3 = made$Option_u8(make, v2);
+					return err3 !== undefined ? rt.Err(err3 as rt.u8) : rt.Ok(out$Option_u8.p);
 				}, undefined, rt.None);
 			} else {
 				const _179: rt.OnceLock<rt.u8 | undefined, rt.None> = cell;
 				result = rt.onceGetOrTryInit(cell, (): rt.Result<rt.u8 | undefined, rt.u8> => {
-					return made$Option_u8(make, option_unwrapOr$0r2bmpr(err$1nbmqmx(result_map$1ma2nl9(rt.onceGetOrTryInit(_179, (): rt.Result<rt.u8 | undefined, rt.u8> => {
-						return made$Option_u8(make, v2 ^ 1);
+					const err2 = made$Option_u8(make, option_unwrapOr$0r2bmpr(err$1nbmqmx(result_map$1ma2nl9(rt.onceGetOrTryInit(_179, (): rt.Result<rt.u8 | undefined, rt.u8> => {
+						const err = made$Option_u8(make, v2 ^ 1);
+						return err !== undefined ? rt.Err(err as rt.u8) : rt.Ok(out$Option_u8.p);
 					}, undefined, rt.None), (_22: rt.u8 | undefined): undefined => {})), v2));
+					return err2 !== undefined ? rt.Err(err2 as rt.u8) : rt.Ok(out$Option_u8.p);
 				}, undefined, rt.None);
 			}
 			if (result.ok) {
@@ -2309,11 +2317,12 @@ export function twin$ref_sync_OnceLock_unit(t: rt.OnceLock<undefined, rt.None>):
 }
 
 /** What `make` makes of `v`, or `v` back as an error for every third byte. */
-export function made$Option_u8(make: (a0: rt.u8) => rt.u8 | undefined, v: rt.u8): rt.Result<rt.u8 | undefined, rt.u8> {
+export function made$Option_u8(make: (a0: rt.u8) => rt.u8 | undefined, v: rt.u8): rt.u8 | undefined {
 	if (rt.u8Rem(v, 3) === 0) {
-		return rt.Err(v);
+		return v;
 	}
-	return rt.Ok(make(v));
+	out$Option_u8.p = make(v);
+	return undefined;
 }
 
 /** What `make` makes of `v`, or `v` back as an error for every third byte. */

ts/fixtures/lang/cells/expected/lib.ts

@@ -3,6 +3,8 @@
 import * as rt from "./rt.ts";
 import { cells } from "./cells.ts";
 
+export const out$Option_u8: { p: rt.u8 | undefined } = { p: undefined as never };
+
 export const out$u64: { err: unknown } = { err: undefined };
 
 export const out$u8: { err: unknown } = { err: undefined };

ts/fixtures/lang/returns/expected/core/bool.ts

@@ -2,6 +2,13 @@
 
 import * as rt from "../rt.ts";
 
+export function thenSome$0b23a33(self: boolean, t: rt.u16): rt.u16 | undefined {
+	if (!self) {
+		return undefined;
+	}
+	return t;
+}
+
 export function then$0w2ymju(self: boolean, f: () => rt.ByteSlice): rt.ByteSlice | undefined {
 	if (!self) {
 		return undefined;

ts/fixtures/lang/returns/expected/core/option.ts

@@ -3,6 +3,20 @@
 import * as rt from "../rt.ts";
 import type * as returns_Error from "../returns.Error.ts";
 
+export function unwrapOr$06r8g1t(self: rt.i128 | undefined, default_: rt.i128): rt.i128 {
+	if (self === undefined) {
+		return default_;
+	}
+	return self;
+}
+
+export function unwrapOr$1j4op5y(self: rt.u16 | undefined, default_: rt.u16): rt.u16 {
+	if (self === undefined) {
+		return default_;
+	}
+	return self;
+}
+
 export function unwrapOr$0r2bmpr(self: rt.u8 | undefined, default_: rt.u8): rt.u8 {
 	if (self === undefined) {
 		return default_;
@@ -24,21 +38,35 @@ export function map$1yogfym(self: [rt.u8, rt.ByteSlice] | undefined, f: (a0: [rt
 	return f(self);
 }
 
+export function map$1cf8u0y(self: rt.u64 | undefined, f: (a0: rt.u64) => rt.u64): rt.u64 | undefined {
+	if (self === undefined) {
+		return undefined;
+	}
+	return f(self);
+}
+
+export function mapOr$1surhce(self: rt.u8 | undefined, default_: rt.u8, f: (a0: rt.u8) => rt.u8): rt.u8 {
+	if (self === undefined) {
+		return default_;
+	}
+	return f(self);
+}
+
 export function okOr$1b6nkwr(self: rt.char | undefined, err: rt.u8): rt.Result<rt.char, rt.u8> {
 	if (self === undefined) {
 		return rt.Err(err);
 	}
 	return rt.Ok(self);
 }
 
-export function okOr$0gtm15y(self: rt.ByteSlice | undefined, err: rt.u8 | undefined): rt.Result<rt.ByteSlice, rt.u8 | undefined> {
+export function okOr$12p77jh(self: rt.ByteSlice | undefined, err: returns_Error.Error): rt.Result<rt.ByteSlice, returns_Error.Error> {
 	if (self === undefined) {
 		return rt.Err(err);
 	}
 	return rt.Ok(self);
 }
 
-export function okOr$12p77jh(self: rt.ByteSlice | undefined, err: returns_Error.Error): rt.Result<rt.ByteSlice, returns_Error.Error> {
+export function okOr$0gtm15y(self: rt.ByteSlice | undefined, err: rt.u8 | undefined): rt.Result<rt.ByteSlice, rt.u8 | undefined> {
 	if (self === undefined) {
 		return rt.Err(err);
 	}

ts/fixtures/lang/returns/expected/core/result.ts

@@ -1,7 +1,17 @@
 // Generated by rust2-ts. Do not edit.
 
 import * as rt from "../rt.ts";
-import type * as returns_Error from "../returns.Error.ts";
+import * as returns_Error from "../returns.Error.ts";
+
+export function eq$11dy112(self: rt.Result<rt.u64 | undefined, returns_Error.Error>, other: rt.Result<rt.u64 | undefined, returns_Error.Error>): boolean {
+	if (!((self.ok ? 0 : 1) === (other.ok ? 0 : 1))) {
+		return false;
+	}
+	if (self.ok) {
+		return rt.eqOption(rt.u64Eq)(self.value, (other as { ok: true; value: rt.u64 | undefined }).value);
+	}
+	return returns_Error.eq$cmp_PartialEq(self.error, (other as { ok: false; error: returns_Error.Error }).error);
+}
 
 export function map$1rffkv6(self: rt.Result<rt.u32, returns_Error.Error>, _: (a0: rt.u32) => rt.u64): rt.Result<rt.u64, returns_Error.Error> {
 	if (self.ok) {