fix #80

src/core/editor/Move.re

@@ -51,14 +51,32 @@ let hstep_tok = (d: Dir.t, tok: Token.t): (Token.t, bool) => {
   };
 };
 
+let push_site = (~onto: Dir.t, site: Zipper.Site.t, ctx: Ctx.t) =>
+  switch (site) {
+  | Between => ctx
+  | Within(tok) => Ctx.push(~onto, tok, ctx)
+  };
+let push_sites = (site: Zipper.Site.cursor, ctx: Ctx.t) =>
+  switch (site) {
+  | Point(Between) => ctx
+  | Point(Within(tok)) =>
+    ctx |> Ctx.push(~onto=L, tok) |> Ctx.push(~onto=R, tok)
+  | Select((l, r)) => ctx |> push_site(~onto=L, l) |> push_site(~onto=R, r)
+  };
+
 let hstep = (d: Dir.t, z: Zipper.t): option(Zipper.t) => {
   open Options.Syntax;
   let b = Dir.toggle(d);
   let+ ctx =
     switch (z.cur) {
     | Select({range: zigg, _}) =>
-      // move to d end of selection
-      return(Ctx.push_zigg(~onto=b, zigg, z.ctx))
+      // move to d end of selection, taking care to update any token marks
+      let (_, ctx_sans_sites) = Zipper.cursor_site(z);
+      let zigg =
+        zigg
+        |> Zigg.map_face(~side=d, Token.focus_point)
+        |> Zigg.map_face(~side=b, Token.clear_marks);
+      return(Ctx.push_zigg(~onto=b, zigg, ctx_sans_sites));
     | Point(_) =>
       let (face, ctx) = Ctx.pull(~from=d, z.ctx);
       let+ tok = Bound.to_opt(face);

src/core/editor/Zigg.re

@@ -49,6 +49,15 @@ let face = (~side: Dir.t, zigg: t) => {
   | Root => Wald.hd(top)
   };
 };
+let map_face = (~side: Dir.t, f, zigg: t) => {
+  let (s_d, top, s_b) = orient(side, zigg);
+  let (s_d, top) =
+    switch (Slope.map_face(f, s_d)) {
+    | Some(s_d) => (s_d, top)
+    | None => (s_d, Wald.map_hd(f, top))
+    };
+  unorient(side, (s_d, top, s_b));
+};
 
 // let x = (1 + [a + b ? c / d : e * f] + 3) + 4 * 5 in x + 1
 

src/core/structure/Token.re

@@ -27,7 +27,8 @@ module Base = {
     ...tok,
     marks: Some(cursor),
   };
-  let put_marks = (marks, tok) => {...tok, marks};
+  let map_marks = (f, tok: t(_)): t(_) => {...tok, marks: f(tok.marks)};
+  let put_marks = marks => map_marks(Fun.const(marks));
   let clear_marks = tok => put_marks(None, tok);
   let pop_marks = tok => (tok.marks, clear_marks(tok));
   let height = tok => Strings.count('\n', tok.text);
@@ -43,6 +44,7 @@ module Molded = {
   [@deriving (sexp, yojson)]
   type t = Base.t(Mtrl.T.t);
 
+  let focus_point: t => t = map_marks(Marks.focus_point);
   let pp = (out, tok: t) =>
     switch (tok.mtrl) {
     | Space(t) =>

src/core/structure/marks/Marks.re

@@ -22,6 +22,10 @@ module Token = {
     };
   let shift = n => Option.map(Step.Cursor.map(Step.shift(n)));
   let union = Options.merge(~f=Step.Cursor.union);
+  let focus_point: t => t =
+    Option.map(
+      Cursor.map((car: Step.Caret.t) => Step.Caret.focus(car.path), Fun.id),
+    );
 };
 
 module Cell = {