wip: sorting out diect pattern stack discipline

may_2025_thoughts.md

@@ -492,4 +492,7 @@ Here's a list of things that need doing:
 * [ ] Original implementation of `butlast` is breaking stack discipline; I don't know why. It ends up returning from evaluating one of the arguments straight into a `load` instruction. Something about tail calls and ternary synthetic expressions and base functions. (For now, I can call `slice` instead of `base :slice` and it works.)
     - Original version of `update` also had this same problem with `assoc`; fixed it by calling the Ludus, rather than Rust, function.
     - I need this fixed for optimization reasons.
+    - I _think_ I just fixed this by fixing tail position tracking in collections
+    - [ ] test this
+* [ ] Dict patterns are giving me stack discipline grief. Why is stack discipline so hard?
 

sandbox.ld

@@ -35,3 +35,6 @@
 & 	& (:background, _) -> state
 & }
 
+let foo = #{:a 1, :b 2, :c 3}
+let #{a, b, ...c} = foo
+

src/compiler.rs

@@ -739,7 +739,9 @@ impl<'a> Compiler<'a> {
                     self.patch_jump(idx, self.len() - idx - 3);
                 }
 
-                self.pop_n(pairs.len());
+                // do this explicitly to keep compiler & vm stacks in sync
+                self.emit_op(Op::Pop);
+                self.emit_byte(pairs.len());
 
                 self.patch_jump(before_load_dict_idx, self.len() - before_load_dict_idx - 3);
                 self.patch_jump(jump_idx, self.len() - jump_idx - 3);