7081198 · jibb · git.iko.soy

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Clarify local type variable scope

7081198iko6 hours ago

docs/open-questions.md+2−2

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unifiedsplit

@@ -18,12 +18,12 @@ On 2026-10-30, @iko adopted gate-free `eq` arguments and map and set keys, treat

19## Questions milestone 2 raises

21−Found while writing [prompts/milestone-2.md](prompts/milestone-2.md), checking it against the doc's examples, and building the checker. The numbering is retained so existing references stay valid. Questions 3, 18, 20, 21, 22 and 23 remain open; the other questions are settled.

21+Found while writing [prompts/milestone-2.md](prompts/milestone-2.md), checking it against the doc's examples, and building the checker. The numbering is retained so existing references stay valid. Questions 3 and 18 remain open; the other questions are settled.

231. **Settled: how the prelude identifies jetted functions.** On 2026-10-30, @iko said the prelude functions have working Jibb implementations, and the compiler recognizes their shapes and uses the Hoon versions so jets can fire.

242. **Settled: how the prelude keeps helpers private.** On 2026-10-30, @iko chose a separate internal prelude module imported by the prelude, without exposing the imported helpers.

253. **The prelude's inventory.** On 2026-10-30, @iko chose to include all names from the listed Hoon library sections, excluding groups the spec explicitly leaves out. All of 3g is included; its Hoon `tone` is exposed as `tone.hoon`, distinct from the styling type. Hoon 1c `step` is exposed as `step.hoon`, leaving the Grammar example's `step` name available. On 2026-10-30, @iko also approved `%$` as a term literal and pattern, so Jibb can write the `%$` case of Hoon `coin`. For parsing sections 4j and 4l, only the explicitly listed `slav` and `slaw` are included; other parser helpers are left out. Jibb's `not` negates a loobean, and Hoon's bitwise `not` is exposed as `not.bit`. @iko also agreed to specifying the complete exported inventory in the doc, building its types and gates needed by the examples in milestone 2, and doing native implementations in milestone 3. Prelude unions such as spaces, roles and tones need names that other modules cannot shadow. The actual inventory and signatures still need to be specified.

26−4. **Settled: a capital in a local `++`.** On 2026-10-30, @iko said it shares the enclosing `++`'s variable of that name; a different type uses a different capital. The Grammar and Decisions record this alongside the earlier aura rules.

26+4. **Settled: a capital in a local `++`.** On 2026-10-30, @iko said it shares the enclosing `++`'s variable of that name if the enclosing `++` also uses it; otherwise the local `++` introduces and generalizes its own variable. For example, `++ inner |= y=A y` shares `A` with an enclosing gate whose sample is `x=A`, but generalizes its own `A` if the enclosing `++` does not use `A`. A different type uses a different capital. The Grammar and Decisions record this alongside the earlier aura rules.

275. **Settled: cells of no items or one.** On 2026-10-30, @iko said a single-item cell is the value and `[]` is an error. The theme's `dark=[tones=[…]]`, a record of one field, must still check.

286. **Settled: a change with no items.** On 2026-10-30, @iko said `m()` is an error. The parser still accepts it; the checker needs to reject it and add a golden case.

297. **Settled: the doc's blocks that aren't whole modules.** On 2026-10-30, @iko agreed to check each in its intended context: the `cmd` and `sub` definitions as prelude source, the Core language tab's `update` inside the todo island, and the Grammar's imports example against fixture files.

docs/prelude-inventory.md+4−4

@@ -20,7 +20,7 @@ Hoon `+$` arms are marked **mold** below; `++` arms can be gates, doors or mold

21`biff`, `bind`, `bond`, `both`, `clap`, `clef`, `drop`, `fall`, `flit`, `hunt`, `lift`, `mate`, `need`, `some`.

23−The following is an audit of the Hoon 135 bodies, not a completed Jibb interface. The current Jibb implementations have only been parsed; the checker and backend do not yet validate or run them.

23+The following is an audit of the Hoon 135 bodies, not a completed Jibb interface. The partial checker infers `fall` and `need`; the remaining written implementations have been parsed, but complete checker validation remains outstanding. Backend validation remains outstanding for all of them.

25| Name | Hoon behavior | Jibb status |

26| --- | --- | --- |

@@ -31,19 +31,19 @@ The following is an audit of the Hoon 135 bodies, not a completed Jibb interface

31| `clap` | Returns the present unit if only one is present; combines both values with a gate if both are present. | Written with one shared type for both units and the combining gate, as @iko chose |

32| `clef` | Applies a gate returning a unit when both inputs are present; otherwise returns an absent unit. | Written |

33| `drop` | Converts an absent unit to an empty list and a present unit to a singleton. | Written |

34−| `fall` | Returns the value of a present unit or the supplied fallback. | Written |

34+| `fall` | Returns the value of a present unit or the supplied fallback. | Written; inferred by the partial checker |

35| `flit` | Returns a gate that wraps a value only if it satisfies the predicate. | Written |

36| `hunt` | Returns the only present unit or chooses between two present values with an ordering gate. | Missing |

37| `lift` | Takes a mold and a unit, then applies the mold to a present value as `bind` does. | Missing; Jibb molds are not callable values |

38| `mate` | Returns the present unit if only one is present; when both are present it returns one if their values are equal and crashes otherwise. | Missing |

39−| `need` | Extracts a present value and crashes on an absent unit. | Written |

39+| `need` | Extracts a present value and crashes on an absent unit. | Written; inferred by the partial checker |

40| `some` | Wraps a value in a present unit. | Written |

42## 2b

44`snoc`, `lure`, `fand`, `find`, `flop`, `gulf`, `homo`, `join`, `bake`, `lent`, `levy`, `lien`, `limo`, `murn`, `oust`, `reap`, `rear`, `reel`, `roll`, `scag`, `skid`, `skim`, `skip`, `slag`, `snag`, `snip`, `sort`, `spin`, `spun`, `swag`, `turn`, `weld`, `snap`, `into`, `welp`, `zing`.

46−The current prelude writes `snoc`, `lure`, `flop`, `join`, `levy`, `lien`, `murn`, `rear`, `reel`, `roll`, `skim`, `skip`, `snip`, `turn` and `weld`. `murn` keeps the present products of its gate in order; `join` inserts a separator between items; `snip` drops the last item, and `rear` returns it or crashes on an empty list. The folds take an explicit initial value as the Prelude table specifies. These implementations still need checker and backend validation.

46+The current prelude writes `snoc`, `lure`, `flop`, `join`, `levy`, `lien`, `murn`, `rear`, `reel`, `roll`, `skim`, `skip`, `snip`, `turn` and `weld`. `murn` keeps the present products of its gate in order; `join` inserts a separator between items; `snip` drops the last item, and `rear` returns it or crashes on an empty list. The folds take an explicit initial value as the Prelude table specifies. The partial checker infers `snoc`, `lure` and `weld` using the validated prelude `list` mold; most other list helpers remain unsupported by that fragment. Backend validation remains outstanding for all of them.

48## 2c

docs/prompts/milestone-2.md+1−1

@@ -62,7 +62,7 @@ The rules are scattered across the tabs. This is a map of them, not a replacemen

62- Hindley–Milner with aura variables: "every expression has a principal type, and there is no general subtyping". A specific atom fits `@`, a specific noun fits `*`, and a more specific aura fits an ancestor in its Hoon aura family, each only in that direction; the reverse needs a check.

63- `@` means any atom, independently at each occurrence. A specific atom such as `@ud` fits where `@` is expected; an `@` value needs a check to fit `@ud`. `@ud` and `@ux` also fit `@u`, and `@tD` fits `@t`, following Hoon aura families; the reverse needs a check. Distinct specific auras remain distinct. `add` takes `[A A]` and returns `A`, with an atom constraint inferred for the shared type variable.

64- Faces are part of record types: `[a=@ b=@]` and `[x=@ y=@]` don't unify. An unnamed position can unify with a faced one and take its face, so `[0 0]` fits `[x=@ud y=@ud]`. A single-item cell `[a]` is `a`; an empty `[]` is an error.

65−- Type variables are capitals, "generalized per `++`". A capital in a local `++` shares the enclosing `++`'s variable of that name; a different type takes a different capital. A body cannot force two distinct capitals to be equal; use the same capital where a type is shared. "A type variable used where an atom is required gains an atom constraint", so `++ clamp |= [lo=A hi=A n=A]`, calling `gth` and `max`, works on any one aura; "It can become nothing more specific: a body that makes `A` a `@ud` or a list is an error." Names "may refer to each other in any order", so infer `++` definitions in dependency order, a group of mutually recursive ones together.

65+- Type variables are capitals, "generalized per `++`". A capital in a local `++` shares the enclosing `++`'s variable of that name if the enclosing `++` also uses it; otherwise the local `++` introduces and generalizes its own variable. For example, `++ inner |= y=A y` shares `A` with an enclosing gate whose sample is `x=A`, but generalizes its own `A` if the enclosing `++` does not use `A`. A different type takes a different capital. A body cannot force two distinct capitals to be equal; use the same capital where a type is shared. "A type variable used where an atom is required gains an atom constraint", so `++ clamp |= [lo=A hi=A n=A]`, calling `gth` and `max`, works on any one aura; "It can become nothing more specific: a body that makes `A` a `@ud` or a list is an error." Names "may refer to each other in any order", so infer `++` definitions in dependency order, a group of mutually recursive ones together.

66- The checker infers a gate-free constraint for `eq` arguments and map and set keys and retains it when a type variable is generalized. The requirement applies recursively to nested values; union-case matching treats gates as opaque. Print a gate-free constraint as `$-([A A] ?) where A contains no gates` and an atom constraint as `$-([A A] A) where A is an atom`; separate multiple clauses with commas, as `where A is an atom, B contains no gates`.

67- Gates may call themselves and their siblings; a non-gate value that depends on itself, even through a gate, is an error. Molds may be recursive, and "recursive molds go by name and module".

68- A sample's mold may be left out: every bare name in a sample binds, at any depth, as in `|=(p title.p)` "when the call fixes the type", `|= [a=@ b]` and `|=(m ~)`.

docs/spec/decisions.md+1−1

@@ -42,7 +42,7 @@ The choices behind the Language tab, made on 2026-10-23; a later date marks a re

43| Empty mold | `!!`, with no values; the expression has any type; pages are `(element !!)`, which keeps islands out of islands | Decided 2026-10-29 |

44| Noun mold | `*` is the noun type, not a type variable; use a capital for a generic type; a value of a more specific noun type can be used where `*` is expected | Decided 2026-10-30 |

45−| Type variables | Capitals, generalized per `++`; a capital in a local `++` shares the enclosing `++`'s variable of that name, and a different type takes a different capital; a body cannot force distinct capitals to be equal, so a shared type uses the same capital; one used where an atom is required gains an inferred atom constraint, and cannot be fixed to a more specific type in its body | Decided 2026-10-30 |

45+| Type variables | Capitals, generalized per `++`; a capital in a local `++` shares the enclosing `++`'s variable of that name if the enclosing `++` also uses it; otherwise it is introduced and generalized locally; a different type takes a different capital; a body cannot force distinct capitals to be equal, so a shared type uses the same capital; one used where an atom is required gains an inferred atom constraint, and cannot be fixed to a more specific type in its body | Decided 2026-10-30 |

46| Loobean mold | `?`, switched with `?-` | Decided 2026-10-26 |

47| Defaults | None | Decided |

48| Modules | Records, not cores | Decided |

docs/spec/grammar.md+1−1

@@ -125,7 +125,7 @@ A mold is only a type: never called on a noun, and with no default. Types are in

125- **Records and tuples**: `[text=@t done=?]`, `[@t ?]`. An empty `[]` is an error. Faces are part of the type, so `[a=@ b=@]` and `[x=@ y=@]` don't unify. An unnamed position can unify with a faced position and take its face, so `[0 0]` fits `[x=@ud y=@ud]`; two different faces don't unify. A record too long for one line can leave its `[` open, with one field per deeper line, as an expression's bracket does.

126- **Unions**: a `+$` with several cases below it. Every union written in Jibb has a name, so one used in a field, a sample, a cast, a gate's mold or an argument gets its own `+$`; only imports bring in unions without one. Tags take their union from context, as Tag resolution describes. Cases must differ as nouns: inhabited cases must differ at some position of their right-nested cells, where one is an atom and the other a cell, or both are different constants. `*`, type variables and molds that can be either, such as `(list A)`, can overlap atoms and cells. `?` counts as the two atoms `%.y` and `%.n`: it is disjoint from cells and overlaps the constants 0 and 1. The empty mold `!!` is disjoint from every case; a cell with an empty position at any depth is itself empty and is also disjoint from every case. A union whose cases don't all differ is rejected.

127- **Containers**: `(list A)`, `(unit A)`, `(set A)`, `(map K V)`, `(mop K V)`, `(qeu A)`, `(jar K V)`, `(jug K V)`.

128−- **Gates**: `$-(A B)`. Type variables are capitals, generalized per `++`. A capital in a local `++` shares the enclosing `++`'s variable of the same name; use another capital for a different type. A body can't force two distinct capitals to be equal; use the same capital wherever a type must be shared. A type variable used where an atom is required gains an atom constraint, so `++ clamp |= [lo=A hi=A n=A]`, whose body calls `gth` and `max`, works on any one aura. It can become nothing more specific: a body that makes `A` a `@ud` or a list is an error.

128+- **Gates**: `$-(A B)`. Type variables are capitals, generalized per `++`. A capital in a local `++` shares the enclosing `++`'s variable of the same name if the enclosing `++` also uses it; otherwise the local `++` introduces and generalizes its own variable. For example, `++ inner |= y=A y` uses the enclosing `A` when its enclosing gate has a sample `x=A`; if the enclosing `++` does not use `A`, `inner` generalizes its own `A`. Use another capital for a different type. A body can't force two distinct capitals to be equal; use the same capital wherever a type must be shared. A type variable used where an atom is required gains an atom constraint, so `++ clamp |= [lo=A hi=A n=A]`, whose body calls `gth` and `max`, works on any one aura. It can become nothing more specific: a body that makes `A` a `@ud` or a list is an error.

129- **Paths**: `/todos` is constant, `/` empty, and `/todo/[id=@ud]` typed by aura. `%/blog/(slug)` is an `qath`, checked against routes and static files.

130- **Generic molds**: `+$ result |$ [V E]` with cases below; `|$` goes only right after a `+$`'s name.

131- **Noun**: `*`, not a type variable; use a capital for a generic type. A value already known to have a more specific noun type, such as `@ud`, can be used where `*` is expected. **Empty**: `!!`.