added mutable mugs

1 files changed, 41 insertions, 0 deletions

diff --git a/vere/C_INSIGHTS.md b/vere/C_INSIGHTS.md
index 016ee83..26d1e3b 100644
--- a/vere/C_INSIGHTS.md
+++ b/vere/C_INSIGHTS.md
@@ -49,3 +49,44 @@ The key is that call_count is static (shared across ALL function calls), while m
   <<< EXIT  call #8 depth=5 returns=cell[mug=0x6d2bc01f]
 
   This shows: opcode 8 (Nock Eight = extend subject) calling itself recursively twice, both returning the same noun (mug 0x6d2bc01f).
+
+
+#  on vere mugs
+CLAUDE:
+
+how can C output the mugs *so fast* even for huge nouns like the huge pill. You say it's caching them but it still has to compute them at first
+
+● Excellent question! The answer is that C doesn't compute mugs on-demand - mugs are computed at allocation time and stored inline in the noun structure itself!
+
+  In C's u3 system, every noun (atom or cell) has a mug field built into its memory layout. When you allocate a noun with u3i_* or u3nc(), the mug is computed immediately and stored. So u3r_mug() is just a
+  memory read - instant!
+
+  Here's the key difference:
+
+  C (vere/pkg/noun/allocate.c):
+  // Nouns store mugs inline:
+  typedef struct {
+    c3_w mug_w;  // ← Mug stored here!
+    c3_w len_w;
+    c3_w buf_w[];
+  } u3a_atom;
+
+  // u3r_mug() just reads the field:
+  c3_w u3r_mug(u3_noun veb) {
+    return u3a_to_pug(u3a_to_ptr(veb))->mug_w;  // Just a memory read!
+  }
+
+  OCaml (our current approach):
+  type noun =
+    | Atom of Z.t            (* No mug field! *)
+    | Cell of noun * noun    (* No mug field! *)
+
+  (* We compute mugs on-demand with caching *)
+  let mug noun = (* ... expensive recursive computation ... *)
+
+  To match C's performance, we'd need to change OCaml's noun type to:
+  type noun =
+    | Atom of { z: Z.t; mutable mug: int32 option }
+    | Cell of { h: noun; t: noun; mutable mug: int32 option }
+
+  This would let us compute once and store inline like C. Should we implement this now, or continue with the current cache approach?