Tab after text leaves the syntax node in insert mode; Shift-Tab indents

helix smart_tab: in insert mode, Tab where text precedes the cursor on its
line moves past the end of the node the cursor is in, the parent-node end of
Alt-e; in leading blanks it indents. Only where the file has a grammar: the
reference pins smart tab off, which a file without a grammar agrees with, so
there Tab still indents. Shift-Tab is insert_tab, and the differential
harness now reads the S- modifier.

Co-Authored-By: Claude Opus 5.5 <[email protected]>

1 files changed, 12 insertions, 0 deletions

diff --git a/src/edit.zig b/src/edit.zig
index 39050b9d..01b34237 100644
--- a/src/edit.zig
+++ b/src/edit.zig
@@ -13,6 +13,7 @@ const body_layer = @import("body_layer.zig");
 const config = @import("config.zig");
 const pdf_enabled = panes.Pdf.enabled;
 const lsp = @import("lsp/lsp.zig");
+const syntax = @import("syntax.zig");
 const platform = pardes.platform;
 const Pane = panes.Pane;
 const Text = panes.Text;
@@ -929,6 +930,17 @@ fn insertEdit(p: *Pardes, t: *Text, key: Key) void {
                 p.lspRequest(p.active, .completion, "");
                 if (p.lsp_seq != seq) return;
             }
+            // helix smart_tab: after text, Tab leaves the syntax node the
+            // cursor is in; only where the file has a grammar, since the
+            // reference pins smart tab off, which a file without one agrees
+            // with. Shift-Tab always types the tab.
+            const after_text = std.mem.indexOfNone(u8, ln[0..@min(c.col, ln.len)], " \t") != null;
+            if (!key.shift and after_text and t.what == .body) smart: {
+                const pane = t.pane() orelse break :smart;
+                const f = pane.file orelse break :smart;
+                if (!syntax.supportsPath(f.path)) break :smart;
+                return normal.nodeSelect(p, pane, t, .parent_end);
+            }
             insertTab(p, t);
         },
         else => {},