Track-B wishlist — compiler features most wanted to unblock libraries + demos

• Type: meta (priority index)
• Status: backlog
• Owner: — (track B requests; track A implements)
• Opened: 2026-06-19
• Relation: the single place track A can pull from to maximize track-B throughput. Each item links its own detail ticket; ranked by how many library/demo deliverables it unblocks. Companion to feature-rtl-conversion-and-bitset-library and the demo/library tickets.

How to read this

Ranked by unblock-leverage (deliverables freed ÷ effort), highest first. "Unblocks" lists the concrete feature-*-library / feature-demo-* work that is waiting on it. Track B has interim workarounds where possible; these remove them.

Ranked wishlist

1. 64-bit operators + literals → bug-64bit-shift-xor-literal-gaps

The single biggest unlock. Three defects in one:

• xor operator unrecognized
• shl/shr by >= ~31 return 0 (64-bit shift is effectively 32-bit)
• 64-bit hex literals truncate to 32 bits (+ UInt64(...) cast unrecognized) Unblocks: feature-hashing-library (SHA/CRC/MD5 need xor + 64-bit rotates), the real feature-random-library (xoshiro256**/splitmix64), 64-bit limbs in feature-bignum-library. Interim: 32-bit LCG RNG shipped; bignum uses base-1e9 Int64-decimal limbs.

2. Case-insensitive builtins → bug-builtin-write-case-sensitive

WriteLn/Write/ReadLn mixed case unresolved (user idents already are case-insensitive). Cheap fix, broad reach. Unblocks: examples/adventure and any FPC-cased demo (lisp/calc/solitaire will all use mixed case). No clean interim (can't lowercase idiomatic source).

3. Loadable sysutils unit → bug-sysutils-unit-hard-skipped

uses sysutils is hard-skipped, so a real lib/rtl/sysutils can't load. Unblocks: the canonical RTL home for IntToStr/Val/StrToInt/Copy/Trim (the feature-rtl-conversion-and-bitset-library surface). Interim: helpers live in lib/rtl/strutils.

4. Generic Copy intrinsic (+ siblings) → feature-copy-intrinsic

Dynarray sub-array (generic over T), 2-arg Copy(s,i), string-family overloads, by-type resolution. Same wall for Delete/Insert/Concat. Unblocks: feature-json-library and string-heavy code broadly. Interim: strutils.Copy(AnsiString) only.

5. Sets from runtime values → feature-language-gaps-from-demos (Gap 1)

[v] with variable v errors; Include/Exclude unimplemented. Unblocks: feature-sat-solver-library, feature-demo-maze set-lane, the sudoku set-lane. Interim: bitmask / boolean-grid stand-ins.

6. Record-returning fn codegen crash → bug-record-fn-codegen-crash

Context-sensitive runtime crash in a record-returning fn with nested loops over dynarray fields (the fused BigMul; possibly the maze segfault). Unblocks: general numeric kernels in feature-bignum-library and beyond. Interim: BigMul rebuilt on simpler primitives.

7. Temporary as const record arg → bug-const-byref-record-param-temp

f(g(x)) illegal when the param is a const record (forces named locals). Unblocks: ergonomic value-style APIs everywhere (bignum, JSON nodes, vectors). Interim: intermediate variables.

8. Generator record-yield + nested-yield → feature-language-gaps-from-demos (Gaps 2-3)

yield from a nested routine; generator of <record> consumed by for-in. Unblocks: feature-demo-chess movegen, generator-based demos. VERIFIED 2026-06-22 (Track A, x86-64):

• Generator-of-record + for-in WORKS via the stackful backend (uses coroutine; function F: TRec; generator; with a record local, yield rec, for r in F do ... reading r.field). This is the chess-movegen case — it is available now. Test shape: a 2-field record generator summing fields → correct.
• Two narrow sub-gaps remain, both non-trivial (NOT quick wins):
  • Stackless generators reject a record local (only ordinal/pointer locals supported (v1), parser.inc ~5659): the one-word-per-local slot model would need multi-word slots + record-copy save/restore + a record CURRENT slot + for-in record read. Use the stackful backend instead.
  • Nested-routine yield (yield inside a nested proc of a generator) fails to parse — cross-frame suspension; a real feature, deferred. So item 8's headline deliverable is satisfied (stackful record generators); the leftovers are edge variants, parked unless a demo demands them.

Also needed (RTL, not pure compiler — noted for sequencing)

• Text file I/O (Assign/Reset/Rewrite/ReadLn(f,...)/Eof/Close, {$I-}/IOResult) — blocks examples/adventure save/load. Track-B RTL work over the kernel-ABI file syscalls, but may need a builtin hook; see the adventure EXPECTED-FAILURES.md F1/F2.

Synapse / networking compiler asks (from Track B)

• Dotted namespace unit names → feature-dotted-unit-names. Synapse's Delphi-POSIX path starts with uses Posix.SysSocket, ...; current PXX looks for only posix.
• {$IF DECLARED(Qualified.Symbol)} → feature-conditional-declared-directive. Synapse probes imported POSIX constants this way in ssposix.inc.

These are not PAL/library workaround targets. Track B can build the Posix.* shim only after the compiler can name and conditionally probe those units.

Already landed (track A)

• const-expr shl/shr/mod folding (632f1c8) — done.
• Item 1 — 64-bit ops (7d4ea89) — DONE. xor + UInt64 alias + aarch64 udiv. splitmix64 byte-identical on all 4 targets. Frees hashing / real RNG / 64-bit bignum.
• Item 2 — case-insensitive Write/WriteLn/Read/ReadLn (3de5d05) — DONE. Frees the FPC-idiomatic / mixed-case demos (adventure, lisp, calc...).
• Item 3 — loadable sysutils (66a3dec) — DONE. uses sysutils loads lib/rtl/sysutils.pas if present (graceful no-op otherwise); compiler's own uses is {$ifdef FPC}-guarded so it can't pull a user RTL unit. Track B: the canonical RTL home is open — migrate the conversion helpers into lib/rtl/sysutils.pas.

Stable v10 pinned (93ad58a) — items 1-3 + COM/ARC interfaces are in track B's pinned binary (binary+builtin coherent; v9->v10).

Recommended next-pull order (track A)

0. Re-verify the codegen crashes on v10 first (cheap, high-info). The bignum/maze segfaults were last seen against pinned v9 mid-WIP; v10 is freshly stabilized + builtin-coherent. Reconstruct the crashing shape from bug-record-fn-codegen-crash and run it. Either it is GONE (close that ticket
   • the maze segfault, drop B's BigMulSmall workaround) or it is REAL (now bisectable on a clean compiler). bug-const-byref-record-param-temp (item 7) can be spot-checked in the same pass.
1. Item 5 — sets from runtime values (feature-language-gaps-from-demos Gap 1): [v] with a variable + Include/Exclude. Self-contained codegen; unblocks THREE demos at once (SAT solver, maze set-lane, sudoku set-lane), all on bitmask/boolean-grid stand-ins today. Highest demos-per-hour.
2. Item 4 — generic Copy (+ Delete/Insert/Concat): unblocks the JSON library + string-heavy code. Bigger (needs by-type overload/generic resolution), so third not second.

Log

• 2026-06-19 — opened by track B as the prioritized pull-list. Top unlock is item 1 (64-bit ops): it frees hashing, real RNG, and 64-bit bignum at once. Items 2-3 are cheap and free the FPC-idiomatic demo + the canonical RTL home.
• 2026-06-19 — items 1-3 all landed by track A (commits above). Items 4-8 remain.
• 2026-06-19 — stable v10 pinned (1-3 + interfaces handed to B). Next-pull order set: re-verify crashes on v10, then item 5 (sets) for max demo unlock, then item 4 (Copy) for JSON.
• 2026-06-19 — stable v11 pinned (90f706a): items 4, 5, 6, 7 all landed. Item 6 (bug-record-fn-codegen-crash) was GONE on v10 (v9 mid-WIP artifact), closed. Item 7 (const-record-temp) fixed. Item 5 (runtime sets + Include/Exclude) done. Item 4 — dynarray Copy done; string-family overloads + Delete/Insert/Concat siblings still open under feature-copy-intrinsic. Items 1-7 now all in B's pinned binary. Remaining wishlist: item 8 (generator record-yield + nested-yield, Gaps 2-3, UNVERIFIED — needs a build) and the Copy siblings. Two pre-existing cross bugs surfaced + filed (bug-const-managed-record-param-byref-crash, bug-dynarray-whole-var-assign-cross; both i386+aarch64, x86-64 fine). Suggested next: item 8 (verify/enable generator record + nested yield → unblocks chess movegen) or the Copy siblings (Delete/Insert/Concat) for JSON breadth.
• 2026-06-20 — track B library upgrades using landed wishlist items:
  • random.pas upgraded from interim 32-bit LCG to xoshiro256** + SplitMix64 (enabled by item 1 — 64-bit ops). LCG retained for constrained targets. Slices 1–2 of feature-random-library done.
  • bignum.pas gained BigMul (schoolbook) and BigSub (enabled by item 6 — record-fn codegen crash fixed). BigMulSmall kept as fast path.
  • sysutils.pas gained FloatToStr, FloatToStrF, StrToFloatDef, StrToFloat, Pos, PadLeft, PadRight. Discovered that the Str builtin breaks when sysutils's Copy is in scope — filed as a compiler gap.
• 2026-06-21 — Synapse/POSIX smoke exposed two new compiler asks: dotted unit names and {$IF DECLARED(...)}. Filed detail tickets and linked them here so Track A can pick them up without Track B inventing Synapse-specific shims.

TRIAGE (2026-06-30, multi-agent verify)

CLOSED — purpose spent. All ranked COMPILER items verified done (64-bit xor/shift/hex; case-insensitive write; sets-from-runtime-values + Include/Exclude; const-record-temp-arg; record-fn-codegen-crash; Copy intrinsic). Residual pointers (Synapse/POSIX RTL, dynarray Delete/Insert, generator edge variants) each live in their own open tickets. Index no longer needed -> done.