Brummel
26fb3459d8
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
4.9 KiB
Str ABI
Heap-Str primitives
The runtime ships a small family of operations that produce or
transform heap-allocated Str values uniformly across static-Str
and heap-Str inputs (the consumer ABI is identical between
realisations — see the Str ABI table below). All take their
input(s) by borrow and return an owned Str. Each is registered as a builtin in
crates/ailang-check/src/builtins.rs, lowered inline in
crates/ailang-codegen/src/lib.rs::lower_app to a call ptr @ailang_<name>,
and backed by a runtime/str.c C helper.
int_to_str : (borrow Int) -> Str— decimal rendering of anInt. BacksShow Intin the prelude.bool_to_str : (borrow Bool) -> Str—"true"/"false". BacksShow Boolin the prelude.float_to_str : (borrow Float) -> Str— type-installed; codegen is reserved and not yet shipped.str_clone : (borrow Str) -> Str— allocates a fresh heap-Str copy of the input's bytes. BacksShow Strin the prelude.str_concat : (borrow Str, borrow Str) -> Str— combines twoStrvalues into a single ownedStr. General-purpose; commonly used in Show bodies for labelled output ((app str_concat "label=" (app int_to_str x))).
The four Show-backers above are not directly observable to the
LLM-author writing a Show <T> instance — the prelude's instance
bodies dispatch into them. str_concat IS directly observable
because the LLM-author calls it explicitly when authoring an
instance body that wants to combine fragments.
Primitive output for Str values goes through io/print_str
directly; values of other primitive types route through the
polymorphic print helper (see prelude classes),
which feeds the heap-Str result of show x into io/print_str.
Equality on Str dispatches via prelude.Eq.eq (Str instance,
lowered by try_emit_primitive_instance_body::eq__Str to a call
into @ail_str_eq with the alwaysinline attribute). Ordering on
Str dispatches via prelude.Ord.compare (Str instance, lowered
by try_emit_primitive_instance_body::compare__Str to a call into
@ail_str_compare then a three-way branch ladder constructing
LT/EQ/GT). The polymorphic helpers ne / lt / le / gt
/ ge resolve via the class layer on top of eq / compare.
There are no primitive operator names == / < / != / etc. in
the language.
Arithmetic operators (+, -, *, /, %) stay primitive and
per-type.
Str ABI. A Str is a pointer to a structure with i64 len at
offset 0 followed by len bytes plus a trailing NUL at offset 8.
Two realisations share this consumer ABI:
| Realisation | Origin | rc_header | Memory |
|---|---|---|---|
| static-Str | string literals (@.str_* LLVM globals) |
none | .rodata, packed-struct <{ i64, [N+1 x i8] }> |
| heap-Str | runtime allocations (int_to_str, float_to_str, ...) |
yes, at payload - 8 |
malloc'd via ailang_rc_alloc(8 + len + 1) |
Every consumer (@fputs, @strcmp, @ail_str_eq,
@ail_str_compare) GEPs +8 from the Str pointer to reach the
bytes, regardless of realisation. The byte-comparison semantics
are inherited from libc strcmp — locale-independent, NUL-
terminated. The print path uses @fputs(bytes, @stdout) so that
(do io/print_str s) writes exactly the bytes of s with no
implicit trailing newline (Gitea #29; the earlier @puts lowering
appended a newline per call).
The heap-Str realisation participates in standard RC (see
memory model): the
rc_header slot eight bytes before the len field is managed
by ailang_rc_alloc / ailang_rc_inc / ailang_rc_dec exactly
like any other RC-allocated cell. The static-Str realisation has
no rc_header slot at all; the bytes at payload - 8 belong to
the previous global in .rodata and reading them is undefined.
The static-Str non-RC invariant is enforced at codegen. Two
mechanisms keep static-Str pointers out of ailang_rc_dec along
every shipping execution path: (1) the non-escape lowering pass
and the move-tracking partial-drop logic
prevent let-binders or pattern-binders for static-Str literals
from reaching scope-close drop emission; (2) the Type::Con { name: "Str" }
carve-outs in field_drop_call and in the Term::App arm of
drop_symbol_for_binder (both in crates/ailang-codegen/src/drop.rs)
route the rare case that does reach drop emission through
ailang_rc_dec, which itself only fires for heap-Str at runtime
(static-Str pointers never carry a live rc_header; if codegen ever
let one through, the runtime would corrupt .rodata-adjacent
memory). No runtime guard backs the invariant up; the codegen
proof is the protection.
Ratified by: crates/ail/tests/e2e.rs.