fix #79

src/core/material/Walk.re

@@ -80,7 +80,7 @@ module T = {
 
   let is_eq = w => List.for_all(Swing.is_eq, Chain.loops(w));
   // note: stricter than !is_eq
-  let is_neq = (w: t) => Swing.is_neq(hd(w)); // && Swing.is_neq(ft(w));
+  let is_neq = (w: t) => Swing.is_neq(hd(w)) && Swing.is_neq(ft(w));
   let is_valid = w => is_eq(w) || is_neq(w);
 
   // let has_sort = w => List.exists(Swing.has_sort, strides(w));

src/core/parser/Melder.re

@@ -135,7 +135,17 @@ let connect_ineq =
   let neq = () =>
     connect_neq(~repair, ~onto=d, onto, ~fill, t)
     |> Option.map(grouted => (grouted, onto));
-  Oblig.Delta.minimize(~to_zero=!repair, f => f(), [eq, neq]);
+  if (repair) {
+    open Options.Syntax;
+    // if repairing, then this means we're molding/remolding and our push of the
+    // current candidate token has reached the top of the local stack ie the nearest
+    // bidelimited container. prioritize maintaining the current bidelimited
+    // container if possible.
+    let/ () = neq();
+    eq();
+  } else {
+    Oblig.Delta.minimize(~to_zero=true, f => f(), [eq, neq]);
+  };
 };
 
 let connect =

src/core/parser/Molder.re

@@ -58,8 +58,12 @@ let mold =
     Token.is_empty(deferred)
       ? None
       : Some(
-          Melder.push(deferred, ~fill, stack, ~onto=L)
-          |> Option.map(((grouted, stack)) => (deferred, grouted, stack))
-          |> Options.get_fail("bug: failed to push space"),
+          {
+            let (fill, slope) = Slope.Dn.unroll(fill);
+            let stack = Stack.cat(slope, stack);
+            Melder.push(deferred, ~fill, stack, ~onto=L)
+            |> Option.map(((grouted, stack)) => (deferred, grouted, stack))
+            |> Options.get_fail("bug: failed to push space");
+          },
         );
   };

src/core/parser/Stack.re

@@ -7,6 +7,11 @@ type t = {
 
 let empty = {slope: Slope.empty, bound: Bound.Root};
 
+let cat = (slope: Slope.t, stack: t) => {
+  ...stack,
+  slope: Slope.cat(slope, stack.slope),
+};
+
 let merge_hd = (~onto: Dir.t, t: Token.t, stack: t) =>
   switch (stack) {
   | {slope: [], bound: Root} => None