VibeLang spec review

2. Details of B

Skip if decision 1 picks C. D7, D24, D241, D269, D271

Rule text, from Opus: "A type annotation may reject a program; it never changes when, whether, or how often an expression is evaluated or run." Open choices: delay as () => F O S or defer { } A; factories marked O S A or plain F; a returned Effect runs through p() O S A or implicitly F; generator kind by syntax O A.

Recommend () =>, a factory marker, explicit p() and EK4802 as an error F O.

3. Names by spelling or by resolved symbol

D135, D148, D152, D208, D295, D311

function runSync(x: number): number { return x }
runSync(1)            // top level: main never runs, exit 0     F O S
x is Number           // a local Number predicate is ignored: false
x is StringMatcher    // same body, another name: true          A

Option B

Resolved symbols for runners, matchers, hatches and exports; data methods from a versioned table, not a self parameter. Prior art: Scheme hygiene, ECMAScript ResolveBinding.

Breaks

Silent, wrong programs only: main starts; a local fork stops capturing fork x.

Recommend B. All four back it.

4. finally in plain functions

ch 15 against ch 17

try { o.a.b } finally { o.c.d }
// plain path: 1 reason ('d'); framed path: 2 reasons ('b', 'd')     Opus's probe

Options

A: keep JavaScript's replacement. B: combine causes as the frame path does O S A. C: keep finally off the plain path O. Prior art: Java 7 addSuppressed. Fable's probe kept both failures.

Breaks

Silent: callers also see the body's failure.

Recommend B, plus a rule that every optimization yields the frame path's Exit O S A.

5. using and resource release

D25, D94

using r = openDisposable()  // its acquireRelease already disposes: ["dispose","dispose"]   Sol
using h = Effect.acquireRelease(() => "h", () => cleanupProgram)
                            // the release never runs; warning EK4802 only               Fable

Option B

An Effect acquisition owns its release and using adds none; a plain Disposable registers one; an unregistered one goes through an adapter that transfers ownership atomically S A. Prior art: TC39 Explicit Resource Management, C# using.

Breaks

Silent: one disposal instead of two.

Recommend B, with EK4802 an error F O. D25 and D94 are still open.

6. Inline module exports

D283, D303

// import { count, bump } from an inline module
bump()
count     // today 0, a snapshot; ECMAScript gives 1          S A

Options

A: snapshots, documented in ch 10 F. B: live bindings, source initialization order, case-sensitive names S A O. Prior art: ECMAScript module records.

Breaks

Silent: importers see current values.

Recommend B.

7. Open error families and exhaustive match

D209, D304; queue item decision:vibelang-sealed-error-families

error Base { _tag: string; code: string }
error Sub extends Base {}
match (e) { when Sub: "sub"; }   // compiles; a Base dies: "No match arm matched Base"

Options

1: seal a family to its file (the queue item; Scala 3, Kotlin sealed). 2: match without default over a non-finite subject is EK4701 F O S A; Rust #[non_exhaustive]. 3: document the gap.

New fact

Sealing alone does not fix it: Sol's probe declares every subclass in one file and still compiles a match that omits one; Opus and Astra agree. Fable's fails on a concrete Base.

Recommend 1, with a checker that counts every subclass and a concrete base, and 2 for every other subject. Compile errors.

8. Handler answer types

D97, D50, EK2119

// clause: const n = resume(); return n.toFixed(1)
// compiles with warning EK2119; runs: TypeError: n.toFixed is not a function     Sol

Options

A: keep the warning. B: one answer type per handler from D50's fixpoint, written when inference cycles; EK2119 an error S A F. Prior art: Eff's handler typing, OCaml 5.

Recommend B.

9. Callback contracts through type aliases

ch 16, D12

function inline(f: (a: number) => number) {}   // accepts an effectful lambda
type Fn = (a: number) => number
function viaAlias(f: Fn) {}                     // EK4301 on the same lambda     O

Options

B: alias or not, an uncontracted function parameter is effect-polymorphic; plain-only is written => A!! O or tagged F. C: explicit effect rows, as in Koka S A.

Recommend B. Aliased callbacks gain channels.

10. Untrusted calls inside plain functions

D101, D263, D282

function viaPlain(n: number): number { return risky(n) }   // compiles
function viaEffect(n) { sleep(…); return risky(n) }         // EK4401     F

Option B

EK4401 in every function; plain code reaches untrusted TypeScript only through a hatch or module F; a call's failures depend only on the callee O.

Recommend B. All four back it; compile errors.