test(series): RED pin for the SMA worked example (#61 headline)

The headline acceptance of #61: the simple-moving-average worked example from design/models/0007-kernel-extensions.md must build via `ail build --alloc=rc`, run, and print the correct moving averages. Green ⇒ the kernel-tier `Series` library extension works end to end (ring-buffer push, financial-style indexing at index 0 = newest, count/total bookkeeping). The fixture is the 0007 worked example with two corrections applied, both verified against the live tool this session: - `>=` is not a surface symbol; the polymorphic Ord helper is `ge` (here on Int operands: total_count vs window size). - `print` on Float emits no trailing newline, so the four averages would concatenate into an unreadable blob. The emit branch now prints the average followed by `io/print_str "\n"`, so each average lands on its own line and the output is deterministic and assertable. (This legibility fix is also queued to be carried back into model 0007.) RED reason (right-for-the-right-reason): `ail check` rejects with [bare-cross-module-type-ref] on `Series` — the kernel-tier module does not exist yet. The fixture itself parses and is otherwise valid. Expected stdout was derived by probing the live %g float formatter independently (the SMA averages are 9/3, 16/3, 17/3, 16/3 over the stream 1,5,3,8,6,2 with window 3): `3.0\n5.33333\n5.66667\n5.33333`. GREEN side (the `series` kernel module + the five ops) is the next mini-mode iteration.
2026-06-02 12:59:34 +02:00
parent b11a6d9883
commit 6b7ee45e49
2 changed files with 172 additions and 0 deletions
@@ -0,0 +1,58 @@
+(module series_sma
+
+  (data FloatList
+    (ctor FNil)
+    (ctor FCons (con Float) (con FloatList)))
+
+  (fn sum_window_step
+    (type (fn-type
+      (params (borrow (con Series (con Float))) (own (con Int)) (own (con Int)) (own (con Float)))
+      (ret (own (con Float)))))
+    (params s n i acc)
+    (body
+      (if (app eq i n)
+        acc
+        (tail-app sum_window_step s n
+          (app + i 1)
+          (app + acc (app Series.at s i))))))
+
+  (fn emit_if_full
+    (type (fn-type
+      (params (borrow (con Series (con Float))) (own (con Int)))
+      (ret (own (con Unit))) (effects IO)))
+    (params s n)
+    (body
+      (if (app ge (app Series.total_count s) n)
+        (seq
+          (app print (app /
+            (app sum_window_step s n 0 0.0)
+            (app int_to_float n)))
+          (do io/print_str "\n"))
+        (do io/print_str ""))))
+
+  (fn run_stream
+    (type (fn-type
+      (params (own (con Series (con Float))) (own (con Int)) (own (con FloatList)))
+      (ret (own (con Unit))) (effects IO)))
+    (params s n input)
+    (body
+      (match input
+        (case (pat-ctor FNil) (do io/print_str ""))
+        (case (pat-ctor FCons v rest)
+          (let s_new (app Series.push s v)
+            (seq (app emit_if_full s_new n)
+              (tail-app run_stream s_new n rest)))))))
+
+  (fn main
+    (type (fn-type (params) (ret (own (con Unit))) (effects IO)))
+    (params)
+    (body
+      (let s (new Series (con Float) 3)
+        (app run_stream s 3
+          (term-ctor FloatList FCons 1.0
+          (term-ctor FloatList FCons 5.0
+          (term-ctor FloatList FCons 3.0
+          (term-ctor FloatList FCons 8.0
+          (term-ctor FloatList FCons 6.0
+          (term-ctor FloatList FCons 2.0
+          (term-ctor FloatList FNil))))))))))))