Files
AILang/examples/eq_ord_user_adt.ail
T
Brummel 26fb3459d8 GREEN: io/print_str byte-faithful via @fputs(@stdout) — closes #29
The runtime print path now writes exactly the bytes of its
argument with no implicit trailing newline. `io/print_str` is
byte-faithful; authors who want a newline emit `(do io/print_str
"\n")` themselves.

## Codegen

`crates/ailang-codegen/src/lib.rs`:
- Module preamble: `@puts(ptr)` → `@fputs(ptr, ptr)` plus
  `@stdout = external global ptr` (libc's `FILE *stdout`).
- Effect-op lowering for `io/print_str`: emit
  `getelementptr +8` then `load ptr, ptr @stdout` then
  `call/tail call i32 @fputs(ptr bytes, ptr fp)`. Identical
  bytes-pointer GEP, distinct sink.
- The pinned IR-shape test renames from
  `print_str_calls_puts_with_bytes_pointer` to
  `print_str_calls_fputs_with_bytes_pointer_and_stdout` and now
  asserts: bytes-GEP present, stdout-load present, both module-
  preamble declarations present, and no `@puts(` call anywhere
  in the emitted IR.

## Why this shape, and not the alternatives

- *Rename `io/print_str` to `io/println_str` (issue #29 option 2)*
  — kept the auto-newline, just relabelled it. AILang's design
  bias is explicit-over-implicit (CLAUDE.md: implicit conversions
  cut). Auto-newline is a hidden runtime augmentation; the rename
  would have preserved it. Rejected.
- *Append `\n` inside the polymorphic `print` (Show-mediated)
  function in `examples/prelude.ail`* — would have been a one-line
  fix. Rejected: `print` is the Show-mediated formatter, not a
  newline emitter; baking a newline into it would have re-imposed
  the same implicit-augmentation problem one layer up, breaking
  callers that legitimately want pure-bytes output.

## Fixture / test sweep

30 `.ail` fixtures whose owning tests asserted line-separated
stdout now emit explicit `(do io/print_str "\n")` after each
print. Tests that asserted on multi-line stdout (`show_print_e2e`,
`floats_e2e`, `str_concat_e2e`, `eq_ord_e2e`, several `print_*`
smoke tests) had their fixtures sweetened the same way; assertions
themselves remain the canonical observable output. Fixtures that
never relied on the newline (no test ever read the absence of one)
were left untouched.

## Migrated metadata

- `crates/ailang-core/tests/hash_pin.rs`: the `ordering_match::main`
  canonical hash is refreshed (`b65a7f834703ffb4` →
  `8ed47b4062ce00f5`). The comment now names both successive
  corpus migrations honestly: the per-type-print-retirement (which
  moved `(do io/print_int x)` to `(app print x)`) AND this
  fputs swap (which wrapped that with `(seq ... (do io/print_str
  "\n"))`).
- `design/contracts/str-abi.md`: the consumer-ABI table now lists
  `@fputs` as the print sink. A prose paragraph documents the
  byte-faithful semantics and references this issue.
- `examples/ordering_match.prose.txt`: regenerated from the
  updated `ordering_match.ail`.
- `crates/ail/tests/snapshots/{hello,sum,max3,list,ws_main}.ll`:
  IR snapshots regenerated via `UPDATE_SNAPSHOTS=1`.
- Stale `@puts` comments in `runtime/str.c`,
  `crates/ail/tests/{e2e,show_print_e2e,print_no_leak_pin}.rs`
  replaced with `@fputs`.

## Verification

- `cargo test -p ail --test print_str_no_auto_newline_e2e` — both
  RED tests from commit c8ecfa3 now pass.
- `cargo test --workspace` — 90 test groups GREEN, 0 failures.
- `cargo build --workspace` — GREEN.
- No new clippy lints (24 warnings pre-existing in
  `crates/ailang-core/src/lib.rs:129`).
- Stats: `bench/orchestrator-stats/2026-05-21-iter-bugfix-print-
  str-fputs.json` — 1/1 tasks, 0 re-loops, 0 review loops.

## Empirical evidence cited

Caught in the 2026-05-21 Qwen3-Coder naming-A/B run
(`experiments/2026-05-21-naming-ab/runs/r1/`): every cohort wrote
`(do io/print_str "...\n")` with explicit `\n` and got doubled
newlines, failing the `t3_main_prints` stdout match across all
three cohorts. The empirical LLM-natural form already assumes the
new (post-this-commit) semantics — confirming the
feature-acceptance test in CLAUDE.md.

closes #29
2026-05-21 12:22:45 +02:00

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(module eq_ord_user_adt
(data IntBox
(doc "A one-field box around an Int, used to demonstrate that the unified mono pass synthesises eq__IntBox from a user-written instance, not from the primitive == operator.")
(ctor MkIntBox (con Int)))
(instance
(class prelude.Eq)
(type (con IntBox))
(doc "Eq IntBox by structural unwrap of the inner Int.")
(method eq
(body (lam (params (typed a (con IntBox)) (typed b (con IntBox))) (ret (con Bool)) (body (match a
(case (pat-ctor MkIntBox ai) (match b
(case (pat-ctor MkIntBox bi) (app eq ai bi))))))))))
(instance
(class prelude.Ord)
(type (con IntBox))
(doc "Ord IntBox by delegating to Int's compare on the inner field.")
(method compare
(body (lam (params (typed a (con IntBox)) (typed b (con IntBox))) (ret (con prelude.Ordering)) (body (match a
(case (pat-ctor MkIntBox ai) (match b
(case (pat-ctor MkIntBox bi) (app compare ai bi))))))))))
(fn main
(type (fn-type (params) (ret (con Unit)) (effects IO)))
(params)
(body (seq (seq (app print (if (app eq (term-ctor IntBox MkIntBox 3) (term-ctor IntBox MkIntBox 3)) 1 0)) (do io/print_str "\n")) (seq (app print (if (app eq (term-ctor IntBox MkIntBox 3) (term-ctor IntBox MkIntBox 5)) 1 0)) (do io/print_str "\n"))))))