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summary_session-2026-10-24-open-arrays-m6.md

summary_session-2026-10-24-open-arrays-m6.md 3.3 KB
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Session 2026-10-24 — open-array M6 (pointer-based 1-D views)

Final open-array milestone: internal 1-D open formals now use the same ArrayView ABI as multi-dimensional arrays, while external C keeps the legacy {count,data} descriptor at the boundary. M6 also does the final docs/gates/tag pass.

Branch: master. Feature state: v3-open-arrays. Gates at the end: suite 300/300, fixpoint OK (3,571,371 bytes), corpus 518/612 compile-OK, 0 crashes.

Numbers

gate start (M5) end (M6)
suite (compiler/run_tests.sh) 299/299 300/300
fixpoint (bootstrap/fixpoint.sh) 3,534,072 B 3,571,371 B
corpus (tools/v3-corpus/corpus.sh) 518/612 518/612, 0 crashes

What landed

Pointer-based 1-D open views

  • MakeOpen1DView builds a 40-byte {count, elemBytes, stride, base, next=0} view from:
    • a fixed or open 1-D array descriptor;
    • a string / UString literal;
    • a row or multi-dimensional subview;
    • a byte-flattened multi array (ARRAY OF BYTE/SBYTE);
    • a scalar byte-buffer compatibility value.
  • LowerDesign treats open 1-D formals as views (lastView); indexing uses ViewIndex, HIGH/LEN read the view count, payload SIZE uses view metadata, and ADR returns base.
  • VAR writes go directly to the caller's payload; row ADR identity is preserved through internal calls.

External C boundary

  • External procedures still receive the legacy {count,data} descriptor:
    • known views are materialized into a temporary legacy descriptor (with the CHAR/UCHAR terminator);
    • VAR results are copied back and the temporary is freed;
    • fixed 1-D arrays/string literals passed directly to C keep the old descriptor.
  • SysShim/FileIO gained GetEnv/getenv support for bootstrap mode (see below).

Bootstrap compatibility

The stage-2 self-host compiler miscompiled when compiler units were themselves built with the view call ABI. The fixpoint now sets V3_LEGACY_OPEN1D=1:

  • compiler units are built with the legacy 1-D call ABI;
  • the resulting compiler still emits pointer-based views for user programs when the variable is absent;
  • the suite runs without the variable, so all user-facing tests exercise the new view ABI.

M2make gained an optional --m2flag pass-through; the fixpoint uses the environment variable instead.

Test coverage

Added t_open_row_adr: a row subview passed to a 1-D open VAR formal must preserve ADR identity. Existing open-array, record, constructor and compiler-session tests remain green.

Remaining

No open-array milestone work remains. A follow-up corpus triage added LFLOAT (suite 301, corpus 519); the remaining cases are classified in triage-corpus-2026-10-24.md. Possible future language work is outside this feature (for example coroutine/protection exceptions and the separate-compilation/library-folder plan).

Commits and tags

commit tag work
04ab8b5 v3-open-arrays-m5 flat record fields and constructors
this code commit v3-open-arrays pointer-based 1-D views + final gates
this docs commit v3-open-arrays-m6-summary final summary/docs
final docs commit v3-session-2026-10-24-open-arrays-m6-end session tag

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