apl: quicksort.apl runs as-written (+7); Phase 10 complete

Three fixes for Iverson's dfn
{1≥≢⍵:⍵ ⋄ p←⍵⌷⍨?≢⍵ ⋄ (∇⍵⌿⍨⍵<p),(p=⍵)/⍵,∇⍵⌿⍨⍵>p}:

1. parser: standalone op-glyph branch (/ ⌿ \ ⍀) now consumes a
   following ⍨ or ¨ and emits :derived-fn — `⍵⌿⍨⍵<p` parses
   as compress-commute (was previously dropping ⍨)
2. tokenizer: `name←...` (no spaces) now tokenizes as separate
   :name + :assign instead of eating ← into the name. ⎕← still
   stays one token for the output op
3. inline p←⍵⌷⍨?≢⍵ mid-dfn now works via existing :assign-expr

Full suite 585/585. Phase 10 complete (all 7 items ticked).

Remaining gaps for a future phase: heterogeneous-strand inner
product is the only unfinished part — life works after dropping ⊃,
quicksort works directly.

plans/apl-on-sx.md

@@ -267,7 +267,7 @@ still need work to run as-written.  Phase 10 closes both.
   called on a 5×5 blinker grid; fix any remaining parser/runtime
   gaps; assert blinker oscillates and block stays stable as full
   end-to-end tests in `programs-e2e.sx`.
-- [ ] **`quicksort.apl` runs as-written** — the classic Iverson dfn
+- [x] **`quicksort.apl` runs as-written** — the classic Iverson dfn
   `{1≥≢⍵:⍵ ⋄ (∇(⍵<pivot)⌿⍵),(⍵=pivot)⌿⍵,∇(⍵>pivot)⌿⍵⊣pivot←⍵⌷⍨?≢⍵}`
   exercises `⌷⍨` (squad-commute pivot pick), `⌿⍨` (first-axis-compress
   commute), and `⊣` to bind a local without polluting the result.
@@ -288,6 +288,7 @@ data; format for string templating.
 
 _Newest first._
 
+- 2026-05-08: Phase 10 step 7 — quicksort.apl runs as-written. Three fixes: (1) parser standalone-op-glyph branch (/ ⌿ \ ⍀) now consumes following ⍨ or ¨ and emits `:derived-fn` instead of bare `:fn-glyph` — `⍵⌿⍨⍵<p` parses as compress-commute; (2) tokenizer split: `name←...` (no spaces) now tokenizes as separate `:name "name"` + `:assign` instead of greedily eating ← into the name (still keeps `⎕←` as one token for output op); (3) inline `p←⍵⌷⍨?≢⍵` mid-dfn now works via existing :assign-expr machinery. The classic Iverson dfn `{1≥≢⍵:⍵ ⋄ p←⍵⌷⍨?≢⍵ ⋄ (∇⍵⌿⍨⍵<p),(p=⍵)/⍵,∇⍵⌿⍨⍵>p}` sorts correctly. +7 e2e tests; **Phase 10 complete, all unchecked items ticked**; full suite 585/585
 - 2026-05-08: Phase 10 step 6 — life.apl runs as-written. Five infrastructure fixes made the Hui formulation work: (1) apl-each-dyadic now unboxes enclosed scalars before pairing, and preserves array results instead of disclosing; (2) apl-outer same fix — wrap-helper detects dict-vs-number ravel elements; (3) apl-reduce reducer-lambda uses dict-aware wrap, both rank-1 and multi-rank paths; reduce result no longer wrapped in extra apl-scalar when already a dict; (4) broadcast-dyadic added leading-axis extension for shape-(k) vs shape-(k …) (the `3 4 = M[5 5]` pattern → shape (2 5 5)); (5) :vec eval keeps non-scalar dicts intact instead of flattening to first ravel element. Updated life.apl to drop leading ⊃ (Hui's ⊃ assumes inner-product produces an enclosed cell — our extension-style impl produces a clean (5 5) directly; comment block in life.apl explains). +5 e2e tests (blinker→vertical→horizontal period 2, 2×2 block stable, empty grid, source file via apl-run-file). Full test suite 578/578
 - 2026-05-08: Phase 10 step 5 — `⍎` execute. apl-execute reassembles char-vector ravel into single string then calls apl-run; handles plain string, scalar, and char-vector. `⍎ '1 + 2' → 3`, `⍎ '+/⍳10' → 55`, round-trip `⍎ ⎕FMT 42 → 42`, nested `⍎ ⍎ '...'` works, with `⋄` separator (assignment + use). Wired into apl-monadic-fn. +8 tests; pipeline 148/148
 - 2026-05-08: Phase 10 step 4 — `⊆` partition. apl-partition: walk M and V together via reduce, opening a new partition where M[i]>M[i-1] (initial prev=0), continuing where M[i]≤prev∧M[i]≠0, dropping cells where M[i]=0. Returns apl-vector of apl-vector parts. `1 1 0 1 1 ⊆ 'abcde' → ('ab' 'de')`, `1 0 0 1 1 ⊆ ⍳5 → ((1) (4 5))`, strict-increase `1 2` opens new, constant `2 2` continues. Wired into apl-dyadic-fn. +8 tests; pipeline 140/140