Brummel
f683f1aec8
Gate-first TDD: widened design_index_pin.rs clause-3 to a hand-rolled
FAITHFUL Sweep-1 superset (case-sensitive digit-anchored line anchors
+ Sweep-1's ^[^/]* path-excluded date + the audit-named
decision-record phrases, case-insensitive); no regex dep; the blanket
iter-detector rejected as unworkable. Sentence-level strip of
faithfully-migrated history/decision-record prose out of 5 contract
files (the audit's 3 spot-checked + roundtrip-invariant.md +
data-model.md the exhaustive scan found) into the decision-record
journal, each replaced by its present-tense contract equivalent;
float-semantics.md stale 'see Str ABI below' -> str-abi.md;
architect_sweeps honesty sweeps re-scoped to design/contracts only
(models/ is the narrative tier) + ailang-architect.md lockstep.
Invariant: clause-3 GREEN => Sweep-1 clean in contracts/.
The prior dispatch correctly BLOCKED on a real plan defect (iso_date
lacked Sweep-1's path-exclusion, over-firing on legit
docs/specs/2026-.. citations); per the two+-defects-in-one-iteration
discipline the audit Resolution mechanism+scope were corrected
upstream in lockstep (f2cdd67) before re-dispatch, not patched a
third time.
Boss-verified independently: cargo test --workspace 646/0,
design_index_pin 4/4 (clause-3 RED->GREEN), architect_sweeps.sh exit
0 'All five sweeps clean' (acceptance criterion 9 met), acceptance
grep CLEAN, 3 docs_honesty_pin pinned runs each exactly 1 contiguous
match. Zero spec/quality re-loops. FINAL design-md-rolesplit
iteration — milestone functionally complete, audited, drift-resolved,
hard gate enforces the honesty spirit.
83 lines
4.1 KiB
Markdown
83 lines
4.1 KiB
Markdown
# Str ABI
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## Heap-Str primitives
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The runtime ships a small family of operations that produce or
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transform heap-allocated `Str` values uniformly across static-Str
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and heap-Str inputs (the consumer ABI is identical between
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realisations — see §"Str ABI"). All take their input(s) by `borrow`
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and return an owned `Str`. Each is registered as a builtin in
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`crates/ailang-check/src/builtins.rs`, lowered inline in
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`crates/ailang-codegen/src/lib.rs::lower_app` to a `call ptr @ailang_<name>`,
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and backed by a `runtime/str.c` C helper.
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- `int_to_str : (borrow Int) -> Str` — decimal rendering
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of an `Int`. Backs `Show Int` in the prelude.
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- `bool_to_str : (borrow Bool) -> Str` — `"true"`/`"false"`.
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Backs `Show Bool` in the prelude.
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- `float_to_str : (borrow Float) -> Str` —
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type-installed; codegen is reserved and not yet shipped.
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- `str_clone : (borrow Str) -> Str` — allocates a fresh
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heap-Str copy of the input's bytes. Backs `Show Str` in the prelude.
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- `str_concat : (borrow Str, borrow Str) -> Str` — combines two `Str`
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values into a single owned `Str`.
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General-purpose; commonly used in Show bodies for labelled output
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(`(app str_concat "label=" (app int_to_str x))`).
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The four Show-backers above are not directly observable to the
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LLM-author writing a `Show <T>` instance — the prelude's instance
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bodies dispatch into them. `str_concat` IS directly observable
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because the LLM-author calls it explicitly when authoring an
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instance body that wants to combine fragments.
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Primitive output for `Str` values goes through `io/print_str`
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directly; values of other primitive types route through the
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polymorphic `print` helper (§"Polymorphic print"), which feeds
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the heap-Str result of `show x` into `io/print_str`.
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`==`, `<`, `<=`, `>`, `>=` REMAIN primitive operators. Class methods
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are accessed by name (`eq x y`, `lt x y`, …), not via these
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operators.
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Arithmetic operators (`+`, `-`, `*`, `/`) stay primitive and
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per-type.
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**Str ABI.** A `Str` is a pointer to a structure with `i64 len` at
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offset 0 followed by `len` bytes plus a trailing `NUL` at offset 8.
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Two realisations share this consumer ABI:
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| Realisation | Origin | rc_header | Memory |
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|-------------|-------------------------------------------------|-----------|-----------------------------------------|
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| static-Str | string literals (`@.str_*` LLVM globals) | none | `.rodata`, packed-struct `<{ i64, [N+1 x i8] }>` |
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| heap-Str | runtime allocations (`int_to_str`, `float_to_str`, ...) | yes, at `payload - 8` | `malloc`'d via `ailang_rc_alloc(8 + len + 1)` |
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Every consumer (`@puts`, `@strcmp`, `@ail_str_eq`,
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`@ail_str_compare`) GEPs `+8` from the Str pointer to reach the
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bytes, regardless of realisation. The byte-comparison semantics
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are inherited from libc `strcmp` — locale-independent, NUL-
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terminated.
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The heap-Str realisation participates in standard RC: the
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`rc_header` slot eight bytes before the `len` field is managed
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by `ailang_rc_alloc` / `ailang_rc_inc` / `ailang_rc_dec` exactly
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like any other RC-allocated cell. The static-Str realisation has
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no `rc_header` slot at all; the bytes at `payload - 8` belong to
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the previous global in `.rodata` and reading them is undefined.
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**The static-Str non-RC invariant is enforced at codegen.** Two
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mechanisms keep static-Str pointers out of `ailang_rc_dec` along
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every shipping execution path: (1) the non-escape lowering pass
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and the move-tracking partial-drop logic
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prevent let-binders or pattern-binders for static-Str literals
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from reaching scope-close drop emission; (2) the `Type::Con { name: "Str" }`
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carve-outs in `field_drop_call` and in the `Term::App` arm of
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`drop_symbol_for_binder` (both in `crates/ailang-codegen/src/drop.rs`)
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route the rare case that *does* reach drop emission through
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`ailang_rc_dec`, which itself only fires for heap-Str at runtime
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(static-Str pointers never carry a live rc_header; if codegen ever
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let one through, the runtime would corrupt `.rodata`-adjacent
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memory). No runtime guard backs the invariant up; the codegen
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proof is the protection.
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Ratified by: `crates/ail/tests/e2e.rs`.
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